F-35B/C and the Ski-Jump?

Unread postPosted: 27 May 2010, 06:24
by Corsair1963
Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons?

RE: F-35B/C and the Ski-Jump???

Unread postPosted: 27 May 2010, 09:01
by spazsinbad
IMHO it is reasonable to believe, otherwise why design the aircraft to NOT achieve the vague benchmark described.

Elsewhere today and before there has been reference to 'Designing JSF for shipboard operations' so we could assume that JSF B & C has been designed with these ships - and its own limitations - in mind. That has been made clear I think.
[The Influence of Ship Configuration on the Design of the Joint Strike Fighter: (1Mb PDF)
http://handle.dtic.mil/100.2/ADA399988
"While the implications of shipboard compatibility have long influenced the design of maritime-based aircraft, the Joint Strike Fighter (JSF) is unique in that the program is centered on the concurrent development of a family of highly common aircraft variants, two of which are to operate from distinctly different ship types. This procurement strategy poses a formidable challenge to the aircraft designer: How to design an air system that meets the unique needs of its multiple warfighter customers while preserving enough commonality to reap the benefits of the "family" approach to design, manufacture, and operational sustainment. This paper describes how the configurations of the United States Navy's aircraft carriers and amphibious assault ships, as well as the United Kingdom Royal Navy's INVINCIBLE-class of carriers, have influenced the basic configurations of the catapult launch / arrested landing (CV) and the short takeoff/ vertical landing (STOVL) variants of the JSF.]
&
One quote amongst many likely from the above PDF:
"AIRCRAFT LAUNCH AND RECOVERY
The JSF aircraft have been sized to take full advantage of the aircraft launch and recovery equipment available on the ships of interest. For example, the CV variant is designed to withstand the tow loads imposed by the C-13 Mod I and Mod 2 catapults, as well as the deceleration loads of the Mk-7 Mod 3 arresting gear."

Image

Re: F-35B/C and the Ski-Jump???

Unread postPosted: 27 May 2010, 16:03
by bjr1028
Corsair1963 wrote:Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons???? :?:


If given enough length to take off in, yes. All a catapult does is cut down that length.

Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 03:52
by Corsair1963
bjr1028 wrote:
Corsair1963 wrote:Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons???? :?:


If given enough length to take off in, yes. All a catapult does is cut down that length.


Define length......

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 04:25
by spazsinbad
As the KPP diagram indicates for USMC with a 20 knot wind and 20 knots of ship speed for 40 knot WOD then 550 feet is enough AFAIK. Similarly with a suitable ski jump (on CVF or LHD) at 12-3 degrees then 450 feet is sufficient in same WOD AFAIK. Here the JSF-B STOVL is the aircraft. How to calculate a free deck takeoff without catapult for the JSF-C variant is beyond my ability (no known performance graphs available).

Because USN carriers are so large I can imagine that with a light fuel load a JSF-C could do a free deck takeoff with a big WOD in an emergency (if all catapults down and A/C going ashore to operate?) with tanking support if they are going to travel any distance. I'm guessing mightily here though. :D

Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 04:31
by sextusempiricus
Corsair1963 wrote:Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons???? :?:


Bizarre question. But, just to humor you, very simple: B model, yes, it's designed for short take offs. Several nations, including the Brits and the Italians, are likely to use the B model to take off from ski-jump-equipped carriers. C model, absolutely not. It's not designed for short takeoffs, and it will likely never be tested on a ski-jump.

You remind me of those people who ask whether an F-16 can take off from and/or land on a carrier. :roll:

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 04:43
by madrat
The wing loading is lower on the C model for near identical TWR. It's not like the B model is going to use its lift fan on a ski jump. I don't see why you'd think the B model could yet the C model could not. Hell, we already know the A model, which uses the same wing as the B, is fully capable of landing on a carrier deck. I bet most people don't know that the A model prototype went through that testing and passed it with flying colors. This is why the C model critics say the A model could do its job. The problem is the safety margin is awfully narrow for the A model, and it is this reason the navy wanted its own dedicated CTOL model.

Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 04:44
by Corsair1963
sextusempiricus wrote:
Corsair1963 wrote:Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons???? :?:


Bizarre question. But, just to humor you, very simple: B model, yes, it's designed for short take offs. Several nations, including the Brits and the Italians, are likely to use the B model to take off from ski-jump-equipped carriers. C model, absolutely not. It's not designed for short takeoffs, and it will likely never be tested on a ski-jump.

You remind me of those people who ask whether an F-16 can take off from and/or land on a carrier. :roll:


Well, obviously you think out of the box even a little! :roll: Funny, that Russia, India, and China. Will use the Naval Models of the Flanker and Fulcrum from Carriers. Yet, no country would consider the F-35C is a similar role.............Then you reply "not" with a constructive counter point but Sarcasm.


Really poor taste...... :nono:

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 05:14
by spazsinbad
madrat, AFAIK it is likely some 'trickery' with the STOVLie bits on the JSF-B can be used to help the short ship/land takeoffs. I'm certain these innovations are being tested in simulators to be later validated in real world. Have not we have seen a 'short takeoff' for JSF-B on land already (prior to first vertical landing)? I'll look for the video later. [video here: http://www.youtube.com/watch?v=ZD-J1KksHUQ] What I don't know is whether the aft nozzle can be rotated somewhat (probably not fully) for augmenting short takeoffs without opening the lift fan doors. Perhaps that is irrelevant in any case. The lift fan door is restricted to below 250 KIAS AFAIK. No big deal to have it open for any kind of takeoff or landing.

[EDIT: As reported here (& elsewhere) http://www.dailytech.com/USMC+Remains+C ... e17998.htm a short takeoff was done at 80 KIAS. Given WOD of 40 KIAS the JSF-B only needs to accelerate to 40 Knots Ground/Deck speed to get airborne - in this example. Probably testing will find different short take off parameters up and down the scale.] WOD = Wind Over the Deck, combination of ship speed and wind speed.

madrat is mistaken about how the X-35 was tested. The CTOL model was flown first then converted to the STOVL aircraft. The USN aircraft was always unique for various reasons explained in the usual PDFs now mentioned many times on these threads but I'll mention one again for reference:

The Influence of Ship Configuration on the Design of the Joint Strike Fighter:

http://handle.dtic.mil/100.2/ADA399988 (1Mb PDF)

JSF Air Vehicle Description
Unique features of the CV variant include a wing with approximately 35% greater area than that on the other two variants, larger tail surfaces, and ailerons on the trailing edges of the wings. These features were added to improve the slow-speed performance and flying qualities required for carrier landings. Additionally, landing gear and other main structural components have been strengthened to withstand shipboard launch and recovery. A launch bar and arresting hook are incorporated to allow catapult takeoff and arrested landings."

This thread is long and boring by now but it does help explain some of the ship ops issues: (read from back to front is probably useful?)
http://www.f-16.net/f-16_forum_viewtopic-t-12631.html

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 05:19
by spazsinbad
And to keep things in perspective about why the CTOL is NOT going to carrier land - look at the maximum Approach Airspeed for the USN variant - 145 Knots. I believe the CTOL will land at a much higher airspeed. Why is this important? Refer to the above PDF for the limitations on the arrest approach speed and other limits - why the USN version is so different as described above.

The JSF-A could carrier land in the same way an F-16 can - via an horrendous touch and go with everyone on deck running for cover.

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 05:48
by spazsinbad
sextusempericus - ever the skeptic - is likely wrong on his assumption that: "...it will likely never be tested on a ski-jump." In the same manner I would be confident that like most USAF fighters of this era and of course any older USN aircraft of note that the CTOL JSF will be tested on a land ski jump along with the USN variant in due course. There is good documentation for both USAF and USN testing of land based ski jumps for older aircraft in the thread: http://www.f-16.net/f-16_forum_viewtopic-t-12631.html (once again starting from the rear working backwards will get to this land ski jump testing info faster).

The USN was obviously interested but also the USAF to allow land ski jumps to be used when runways damaged, using available good runway with ski jump (or taxiways) for such 'emergency' ski jump takeoffs when required.

http://www.f-16.net/f-16_forum_viewtopi ... t-225.html

Aircraft Operations from Runways with Inclined Ramps (Ski Jump) USAF testing 1991:

http://handle.dtic.mil/100.2/ADA237265 (0.9Mb PDF)

Good bits of this 'ski jump' inspired testing by USAF in 1991 (mentioning also USN ski jump testing) are in graphic below. Original PDF of course has much more....

http://attach.high-g.net/attachments/us ... st_852.gif

Image

http://attach.high-g.net/attachments/ho ... en_992.jpg

Image

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 06:07
by Corsair1963
If, India does purchase the F-35 at some point in the future for its Carriers. Would it order both F-35B's for the first IAC-1. To be followed by F-35C's for its Larger and Catapult Equipped IAC-2??? Or would it for go the F-35B and just operate the F-35C from both ships???

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 06:22
by spazsinbad
Corsair1963, do you mean last sentence to be: "... Or would it for go the F-35B and just operate the F-35B from both ships???" You would probably guess correctly that I am prejudiced/predisposed to answer 'hell yes' to the above. :D

Here is a news item with a graphic that may be more relevant than what I want:

[here also: http://knol.google.com/k/vijainder-k-th ... dhy2mq/61#]

Second Indian Aircraft Carrier will be larger, says Indian Naval Chief

http://kuku.sawf.org/News/61487.aspx

December 02, 2009, (Sawf News) - The second indigenously built aircraft carrier, IAC-2, will be larger and feature heavier fighter aircraft.

The IAC-2 could undergo some design changes, Naval Chief Admiral Nirmal Verma indicated while speaking to the press on Wednesday, December 2, ahead of Navy Day on December 4, 2009.

"We are re-looking at the design. It won't be a copy of what we have today," he said

He said a concept study by the Directorate of Naval Design is currently underway 'for more capable carrier-borne aircraft' for the IAC-2.

The Navy is leaning towards a 50,000 tons carrier capable of launching heavier aircraft using a steam catapult, rather than the ski-jump on the Gorshkov / Vikramaditya.

The Navy has earlier indicated it prefers the Electromagnetic Aircraft Launch System (Emals) on its new aircraft carriers.

The Navy issued an RFI (request for information) to several global aviation majors, including American Boeing, French Dassault and Russian MiG companies, for 'an alternate deck-based aircraft' in November.

"Information is being sought to acquire over 40 fighters for the 40,000-tonne IAC-1 (indigenous aircraft carrier), being built at the Cochin shipyard and expected to roll out by 2014-2015 now, and IAC-2, which will follow later," a source told TOI.


http://media.sawfnews.com/images/Blogph ... arison.jpg

Image

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 07:48
by spazsinbad
The long thread about USMC/RN & JSF-B ops has a more detailed story (replicated here somewhat: http://www.kitmaker.net/modules.php?op= ... 873&page=1

Joint Strike Fighter has Pax River debut By Rick Thompson Pax River Public Affairs January 7, 2010

http://www.dcmilitary.com/stories/01071 ... 8154.shtml

"...The F-35B and F-35C will be tested and developed at Pax River, which will host a total of eight aircraft at the peak of the testing program.

The centerfield complex will be used to test these capabilities, including vertical landings on pads mimicking those found on land and on the LHD class of ships; short-distance takeoffs using the ski jump which is similar to those found on U.K. carriers; and flight performance testing on the EAF.

Expeditionary Airfields are mobile systems that allow U.S. Marines to quickly build functioning airfields in mission critical areas that do not support a standard-use airfield. These areas allow the JSF to perform missions in any terrain. Additional testing activities to occur at Pax River include carrier approach and landing flights, software and aircraft systems development, and aircraft certification testing.

The JSF SDD program operations at Pax River are expected to continue through 2013 although the F-35’s presence here likely extend well into the future. Aircraft equipment and systems requirements continually evolve, resulting in the continued need for follow-on test and evaluation...."

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 08:47
by spazsinbad
This summary has been made from a Sept 2005 report - I gather Pax River is up to speed today....

Ship Suitability Testing – Preparing for the Future Mr. Ronald J. Harney Senior T&E Engineer for Ship Suitability Naval Air Warfare Center 21 Sept 2005

http://ftp.rta.nato.int/public//PubFull ... 162-07.pdf (0.6Mb) [MP-051-PSF-26.pdf]

"2.0 SHIP SUITABILITY T&E
2.1 Fixed-Wing Testing

The Fixed-Wing Ship Suitability T&E Branch performs all flying qualities, performance, and structural tests associated with Navy manned and unmanned fixed wing platforms. The bulk of the testing involves catapult and arrested landing structural demonstrations of new and modified aircraft. Structural demonstrations as well as steam ingestion catapult tests are conducted at shore based catapult and arrested landing facilities located at the Naval Air Warfare Center, Patuxent River, MD. This group also supports launch and recovery hardware developmental testing at the Naval Air Warfare Center, Lakehurst, New Jersey. Flying qualities and performance (FQ&P) testing is first conducted shore based, then evaluated at the ship. The shore-based tests are used to define the minimum acceptable approach airspeed and give the testers an initial look at airplane flying qualities in the more benign shore based environment. Once we are satisfied with the shore-based results from a structural suitability and a FQ&P standpoint, we then take the airplane to the ship. Some of the most exciting shipboard tests are the minimum catapult end airspeed tests where we determine the slowest safe speed for catapult flyaway. Other shipboard launch tests include establishing crosswind limits, evaluating launches off waist catapults, evaluating the affects of low energy launches (low gross weights, high winds) on flyaway, and determining aircraft trim requirements for symmetric and asymmetric store configurations. Recovery testing includes establishing crosswind limits, evaluating bolter and waveoff performance, and evaluating handling qualities at high wind-over-deck conditions. Additional testing includes evaluating compatibility with shipboard facilities and support equipment. Examples include conducting heavy weather tie down, canopy opening under high wind conditions, dynamic tipback following an arrestment, and hangar bay towing and spotting.....

...The JSF T&E program will also challenge us from a magnitude and complexity standpoint. The JSF STOVL and CV test aircraft will be able to generate large amounts of data. Our ability to evaluate all of this data in a timely manner will stretch our manpower resources. Another challenge is the logistics of setting up data collection and analysis hardware on the ship. While portable data station capability has significantly increased over the past ten years, giving us the ability to monitor and analyze thousands of parameters, we are normally limited by the amount of space aboard a ship to set-up these data stations. Automated data collection and analysis databases are being developed, largely through the efforts of our testers. They are researching many different areas including tools to speed up flight test analysis, predictive tools to reduce dynamic interface test requirements, and PC based tools to evaluate visual landing aids.

6.5 Test Procedures – Learning from the Past
As described above, we must develop new and innovative methods for testing future capability. However, we are also challenged in our need to learn from testing conducted in the past. We have seen a significant turnover in personnel since the last time we conducted sea trials with a STOVL aircraft. With upcoming AV-8B testing on LPD-17 and testing of the new JSF F-35B STOVL, we will research and understand the test techniques utilized during AV-8B testing last conducted in the 1980’s. Additionally, we will be required to demonstrate ski-jump capability on the JSF F-35B. Much of our expertise in conducting ski jump testing has diminished over time.

7.0 SUMMARY
In summary, we are entering a significantly challenging period of ship suitability T&E. The ship suitability test and evaluation testers must be able to utilize cutting edge tools to enable safe and efficient conduct of these tests while mixing in the lessons learned from testing that was conducted as far back as 40 years. From modelling and simulation to test planning aids to the latest capabilities in instrumentation and data analysis, we must challenge ourselves to conduct testing with safety as the number one priority while still giving the Fleet the best product possible. All the while, we are challenged to conduct this testing with less personnel than history tells us is necessary. This paper does not answer many questions, but poses the challenges that are ahead of the Ship Suitability Test and Evaluation group."

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 09:24
by spazsinbad
PAX River development finished 2010:

For Andy Macyko, what he’ll miss is the people 08 Mar 2010
http://www.paxpartnership.org/index.cfm ... D&NW_ID=22
"...From an operational point of view, ‘‘We have identified mission customers’ support requirements for new and legacy programs,” Macyko said. ‘‘We have finished a $15 million airfield renovation project, and built mission-unique facilities such as the ski jump ramp, hover pads and the expeditionary airfield for the F-35B Lightning II aircraft....”
______________

Good JSF-B short takeoff video: (4.3Mb .WMV)

http://www.lockheedmartin.com/data/asse ... ff_ppt.wmv

Looks to me as though the rear nozzle is rotated during liftoff but I could be wrong. Can't see this nozzle during initial takeoff run but that may be camera angle or whatever.

Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 10:45
by sextusempiricus
madrat wrote:The wing loading is lower on the C model for near identical TWR. It's not like the B model is going to use its lift fan on a ski jump. I don't see why you'd think the B model could yet the C model could not. Hell, we already know the A model, which uses the same wing as the B, is fully capable of landing on a carrier deck. I bet most people don't know that the A model prototype went through that testing and passed it with flying colors. This is why the C model critics say the A model could do its job. The problem is the safety margin is awfully narrow for the A model, and it is this reason the navy wanted its own dedicated CTOL model.


Wrong, wrong, wrong. Have you actually seen a B model performing a short take off??? It uses its lift fan, with the rear nozzle vectored downward. And when did the X-35A ever, ever, ever land on a carrier? The X-35C flew simulated approaches, but it did have the larger wing, the additional flaps, the larger tail planes, etc. You need to get your facts straight.

Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 10:50
by sextusempiricus
spazsinbad wrote:sextusempericus - ever the skeptic - is likely wrong on his assumption that: "...it will likely never be tested on a ski-jump." In the same manner I would be confident that like most USAF fighters of this era and of course any older USN aircraft of note that the CTOL JSF will be tested on a land ski jump along with the USN variant in due course. There is good documentation for both USAF and USN testing of land based ski jumps for older aircraft in the thread: http://www.f-16.net/f-16_forum_viewtopic-t-12631.html (once again starting from the rear working backwards will get to this land ski jump testing info faster).

The USN was obviously interested but also the USAF to allow land ski jumps to be used when runways damaged, using available good runway with ski jump (or taxiways) for such 'emergency' ski jump takeoffs when required.

http://www.f-16.net/f-16_forum_viewtopi ... t-225.html

Aircraft Operations from Runways with Inclined Ramps (Ski Jump) USAF testing 1991:

http://handle.dtic.mil/100.2/ADA237265 (0.9Mb PDF)

Good bits of this 'ski jump' inspired testing by USAF in 1991 (mentioning also USN ski jump testing) are in graphic below. Original PDF of course has much more....

http://attach.high-g.net/attachments/us ... st_852.gif

Image

http://attach.high-g.net/attachments/ho ... en_992.jpg

Image


I'm well aware of the Hornet being tested with a ski-jump. Its ability to do so never led to an operational capability for a reason.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 12:42
by spazsinbad
SE, nevertheless the USN did test their aircraft with the ski jump to get excellent results as was the case with the USAF testing. The USN has had a strong 'dislike' of ski jumps for various reasons (so as not to encourage the USMC I would imagine) but then again I'm guessing. The USN do have the correct aircraft to be catapulted from their catapults and of course they can be arrested at any time (within limits). No big deal. One can see how the USAF was more interested in ski jumps for reasons stated above.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 13:07
by spazsinbad
Some more info from similar Indian thread....: http://www.f-16.net/f-16_forum_viewtopic-t-13222.html

Go to page: http://tiny.cc/GqjXw
Click on “See First Page” and a PDF page will open up with information about testing, I don’t have full PDF.
CTOL Ski Jump: Analysis, Simulation, and Flight Test” John W. Clark Jr.* and Marvin M. Walterst Naval Air Development Center, Warminster, Pennsylvania “In the past several years, the ski-jump (ramp-assisted)launch concept has received considerable attention within the U.S. Navy. The specific goal was set (and achieved) to demonstrate through flight test the feasibility of, and quantify performance gains from, ski-jump launch of the T-2C, F-14A, and F/A-18A aircraft using a 100-ft ramp with variable end angles of 6 and 9 degs. The analysis, piloted simulation, performance predictions, and flight safety considerations leading to flight test, as well as a compari-son of analytical predictions with flight test results for the three aircraft, are discussed. The developed analytical capability, although somewhat conservative, proved to be highly effective in preparation for, and support of, the flight test and in successfully predicting the 40-60% reduction in takeoff distance demonstration in flight test.
&
26 September 1983 – The first takeoffs of an F/A-18 Hornet from a ski-jump ramp were conducted at NAS Patuxent River, Md. The tests were part of an evaluation of conventional jet aircraft using an upward curved ramp to shorten takeoff roll.” http://www.history.navy.mil/avh-1910/PART11.PDF (page 10)

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 13:20
by spazsinbad
Some more Olde Worlde History:

UNITED STATES NAVAL AVIATION 1910–1995 PART 10 The Seventies 1970–1980

http://www.history.navy.mil/avh-1910/PART10.PDF (1Mb)

26 March 1979 The AV-8A Harrier was used at NATC Patuxent River, Md., to test a new ski jump ramp developed by the British to cut down the takeoff distance for the Harrier. The new ski jump ramp was designed with a 12-degree angle of elevation and was 130 feet long. The total takeoff distance for a Harrier using the new ramp was 230 feet compared with the 930-foot runway necessary for a Harrier to make a no catapult, flat-surface launch. NATC Patuxent River was evaluating the ramp for possible use in the fleet.

31 July 1980 A T-2C Buckeye was launched successfully from a fixed-angle, three-degree ski jump at Naval Air Test Center, Patuxent River, Md. This launch was the first part of feasibility demonstrations to evaluate the use of ramps for takeoffs by conventional, as opposed to V/STOL, aircraft.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 13:34
by spazsinbad
Interesting (to me anyway) factoid about Rafale and de Jump de Ski (don't know if it has been put into practice though?).

http://www.flightglobal.com/pdfarchive/ ... 02611.html

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 15:04
by spazsinbad
PAX River Ski Jump Facilities 2009: http://www.navair.navy.mil/nawcad/index ... 38819A5C10

Centerfield Short Take Off/Vertical Landing (STOVL)
The Centerfield STOVL (Short Takeoff/Vertical Landing) was completed in 2009, to support the developmental testing of the Joint Strike Fighter (JSF) F-35B STOVL aircraft. Located in the centerfield area at NAS Patuxent River, the STOVL Centerfield Facility consists of an AM-2 Expeditionary Airfield (EAF), an AM-2 Vertical Takeoff and Landing (VTOL) pad within a painted LHD deck outline, a Ski Jump, and a grated Hover Pit.
The EAF and VTOL Pad AM-2 surfaces are representative of current US Marine Corps austere/forward deployed basing capabilities. These surfaces will be used to test F-35B compatibility during Short Takeoff (STO), Vertical Landing (VL), and Slow Landing (SL).
The Ski Jump, built to match the profile of the UK HMS Invincible Class Ships, will provide a land-based test site for unique ship compatibility. The Hover Pit was constructed during the X-32/X-35 concept demonstration phase of the JSF Program and has supported operations with British Sea Harrier aircraft.
The Hover Pit also provides a means to perform STOVL mode engine runs without ground effects by ducting exhaust thrust away from the aircraft through a series of vanes below the top grating of the pit."

http://www.navair.navy.mil/nawcad/img/u ... 20Site.jpg

Image

Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 21:33
by bjr1028
Corsair1963 wrote:
bjr1028 wrote:
Corsair1963 wrote:Is it reasonable to believe that the F-35B and F-35C. Can take off from a Ski-Jump equipped Carrier with a Full Load of Fuel and a Modest Load of Weapons???? :?:


If given enough length to take off in, yes. All a catapult does is cut down that length.


Define length......


Distance required to takeoff.

For the F-35C, cat assisted it can definitely take off on 300ft cats and probably take off from 250ft cats. Unassisted its somewhere between 500-800 feet depending on load.

madrat wrote:The wing loading is lower on the C model for near identical TWR. It's not like the B model is going to use its lift fan on a ski jump. I don't see why you'd think the B model could yet the C model could not. Hell, we already know the A model, which uses the same wing as the B, is fully capable of landing on a carrier deck. I bet most people don't know that the A model prototype went through that testing and passed it with flying colors. This is why the C model critics say the A model could do its job. The problem is the safety margin is awfully narrow for the A model, and it is this reason the navy wanted its own dedicated CTOL model.


Neither the A or B are strengthened for hard carrier landings. The STOVL models do "soft" landings.

spazsinbad wrote:And to keep things in perspective about why the CTOL is NOT going to carrier land - look at the maximum Approach Airspeed for the USN variant - 145 Knots. I believe the CTOL will land at a much higher airspeed. Why is this important? Refer to the above PDF for the limitations on the arrest approach speed and other limits - why the USN version is so different as described above.

The JSF-A could carrier land in the same way an F-16 can - via an horrendous touch and go with everyone on deck running for cover.


With the landing gear snapping off and the air force its not too badly damaged to be repaired...and the navy having to deploy the barrier to keep it from skidding of the deck.

Corsair1963 wrote:If, India does purchase the F-35 at some point in the future for its Carriers. Would it order both F-35B's for the first IAC-1. To be followed by F-35C's for its Larger and Catapult Equipped IAC-2??? Or would it for go the F-35B and just operate the F-35C from both ships???


They won't order the F-35B. The F-35C could operate off of virrat..

spazsinbad wrote:Corsair1963, do you mean last sentence to be: "... Or would it for go the F-35B and just operate the F-35B from both ships???" You would probably guess correctly that I am prejudiced/predisposed to answer 'hell yes' to the above. :D

Here is a news item with a graphic that may be more relevant than what I want:

[here also: http://knol.google.com/k/vijainder-k-th ... dhy2mq/61#]

Second Indian Aircraft Carrier will be larger, says Indian Naval Chief

http://kuku.sawf.org/News/61487.aspx

December 02, 2009, (Sawf News) - The second indigenously built aircraft carrier, IAC-2, will be larger and feature heavier fighter aircraft.

The IAC-2 could undergo some design changes, Naval Chief Admiral Nirmal Verma indicated while speaking to the press on Wednesday, December 2, ahead of Navy Day on December 4, 2009.

"We are re-looking at the design. It won't be a copy of what we have today," he said

He said a concept study by the Directorate of Naval Design is currently underway 'for more capable carrier-borne aircraft' for the IAC-2.

The Navy is leaning towards a 50,000 tons carrier capable of launching heavier aircraft using a steam catapult, rather than the ski-jump on the Gorshkov / Vikramaditya.

The Navy has earlier indicated it prefers the Electromagnetic Aircraft Launch System (Emals) on its new aircraft carriers.

The Navy issued an RFI (request for information) to several global aviation majors, including American Boeing, French Dassault and Russian MiG companies, for 'an alternate deck-based aircraft' in November.

"Information is being sought to acquire over 40 fighters for the 40,000-tonne IAC-1 (indigenous aircraft carrier), being built at the Cochin shipyard and expected to roll out by 2014-2015 now, and IAC-2, which will follow later," a source told TOI.


http://media.sawfnews.com/images/Blogph ... arison.jpg

Image


I foresee a license build of a CVF here...or worse the brits selling them PoW.

spazsinbad wrote:SE, nevertheless the USN did test their aircraft with the ski jump to get excellent results as was the case with the USAF testing. The USN has had a strong 'dislike' of ski jumps for various reasons (so as not to encourage the USMC I would imagine) but then again I'm guessing. The USN do have the correct aircraft to be catapulted from their catapults and of course they can be arrested at any time (within limits). No big deal. One can see how the USAF was more interested in ski jumps for reasons stated above.


The rotary wing and ground marines have a dislike of ski-jumps as well as they would take between 1 and 3 landing spots,

Ski-Jumps are great compared to flat surface landings. Compared to catapult launches they require 50-75% more deck space to launch an aircraft. With a STOVL aircraft this is negated not requiring an arrested landing and the angled deck it requires. Although you do give a lot in order to have STOVL aircraft. In the F-35's case its not insignificant reductions in payload and range.

spazsinbad wrote:Interesting (to me anyway) factoid about Rafale and de Jump de Ski (don't know if it has been put into practice though?).

http://www.flightglobal.com/pdfarchive/ ... 02611.html


It wasn't. The Clemenceau class carriers were intended to operate rafale while the CdeG and Richelieu were under construction. The Rafale was too happy to operate with the old 50m british BS-5 cats. The plan was to add ski jumps to the end of the two old carriers to help the Rafale's take off. They tried it a couple of times and it didn't go over too well. They ended up retiring Foch early and going only with CdeG (especially after Richelieu was cancelled).

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 31 May 2010, 22:58
by spazsinbad
bjr1028, thanks for your info. Here are some Art Nalls thoughts about STOVL ops USMC wise:

Hawker Association Newsletter 16 Spring 2007 - Updated on 16Mar2007

http://myweb.tiscali.co.uk/hawkerassoci ... flyon.html

"....[Art Nalls USMC Bio] ...operational experience in the AV-8A, was a test pilot for the early AV-8Bs and project test pilot for the TAV-8B. I also have over six hours of flight time in Harriers and Skyhawks without the engine running (during air-start testing), hundreds of shipboard landings and was a test pilot for Harrier trials including high angle-of-attack tests, weapons tests, asymmetric take-off and landing tests, and shipboard ski-jump tests. I was fortunate to hit the programme when everything needed to be explored and we only had three pilots to do it all.

Editor's Note. In answer to some questions raised by the above, Art sent the following.....
I was a military test pilot at Pax River, having graduated from the USAF Test Pilot (TP) School with Class 85A. At that time the new AV-8B was being introduced and there was no shortage of work. In fact, I had been offered a TP job Edwards AFB while a student there but Marine Colonel Harry Blot, my former CO, told me in no uncertain terms that if I accepted a job testing for the Air Force I was to stay there and never come back to the Marines; I had been sent to Edwards to become a qualified TP so had better get back to work for the Marines!

I was the project officer for the ski-jump testing aboard ship. The first ship was the Italian Navy Garibaldi, with a 6 deg ramp, designed specifically for Harriers. The ship must have been designed by someone who had never actually been aboard a fighting ship - centre deck elevators, centre hangar bay with passages round the outside, fuel lines running round the ship perimeter, no deck-edge scuppers and no lights - but it does look good!

Anyway, we did the tests and provided the launch bulletin for them. The second ship was the Spanish Navy Principe de Asturias with a 12 deg ramp. This had a much better configuration being based on the unbuilt US designed Sea Control Ship sponsored by Admiral Zumwalt, USN.

The ski-jump so impressed me that I authored several technical papers and was a huge advocate for the USMC to push the USN to install it in our amphibious ships (LHDs). We could then use the single flight deck as essentially two runways; the helos launching from the stern, the Harriers from the bow. There is nothing that can be loaded on a Harrier that it can't take off with from 400 ft with 15 knots wind over deck - absolutely nothing - and the flight deck is 800 ft long on the LHDs.

Doubled take off performance, increased inherent safety from the launch trajectory and no moving parts. Seemed like a no-brainer to me but the USN didn't want to jeopardise their big deck carriers. I even attempted to orchestrate a cross-deck operation with the Russian ski jump ship Tiblisi.

Towards the end of my flight testing career I conceived and got official approval to take a test team to Russia to explore the YAK-141 supersonic VSTOL fighter and to fly and report on the YAK-38 Forger. I was the first western TP to do this."
Also:
http://www.nallsaviation.com/biography.html

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 01 Jun 2010, 03:10
by madrat
With all the brain power invested in these technologies I'm surprised nobody has came up with a ramped monorail launch that takes place off the main deck and places the planes on a climb at release. Granted you would want the plane to sit on a dolly that transverses the monorail. Or perhaps set a common standard - like the trains have - for a universal slider system incorporated into existing aircraft. Once the plane is attached to the monorail's dolly you could withdraw the landing gear and eliminate that much extra drag. All that deck space taken up for launching CTOL fighters seems wasteful. You would be able to launch several planes simultaneously or recover planes at much closer intervals to planes leaving.

I'm thinking use gravity by making the rail an ogee-path (think S-curve) first downwards then back upwards. You wouldn't want to have the aircraft launching at the same exact level as the flight deck or the rails would have to be further out from the side of the existing beam. But having five catapults available at any one time, with one of them specialized for launching heavy-laden aircraft - utility and AEW assets - would add flexibility in operations.

If you could commit to vertical landings then a rail launcher like I proposed would allow you to take a destroyer or frigate and give your Harrier/F-35B a substantial takeoff boost. Rails for launching would lay on the outskirts of the ship, eliminating the need for the whole flattop of a carrier. You would be basically a conventional takeoff with a vertical landing platform. You would suffer not having much tarmac space, but your planes could takeoff with a big relative payload. And if you have the ability to operate heavier warplanes like this than you could commit to a hangar on nuclear cruisers for 5-8 aircraft rather than 2-3 as it is now.

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 01 Jun 2010, 03:47
by spazsinbad
madrat, for sure over the years there have been many propositions to vary aircraft ship ops. Here is another one at random, other references not kept during a recent search included crossed runways on a ship for coordinated takeoffs and landings, search the web for a bunch of stuff:

http://books.google.com.au/books?id=PdQ ... &q&f=false

RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 01 Jun 2010, 03:53
by spazsinbad
And to consolidate the (edited) text from the USAF trials (with info about USN experience) of ski jumps - here 'tis....

AIRCRAFT OPERATIONS FROM RUNWAYS WITH INCLINED RAMPS (SKI-JUMP) by Elijah W. Turner

http://handle.dtic.mil/100.2/ADA237265

This effort was begun in 1982 to investigate the use of inclined ramps (Ski-Jumps) to launch aircraft from short runways as a possible solution to the runway denial problem in Europe. In 1983, Ski-Jump was briefed to the Airbase Survivability Steering Group and "Phase 1 - Analytical Study" was authorized. This report covers work done from January 1982 through July 1986.

ABSTRACT
The use of inclined ramps to launch aircraft from short runways is proposed as a possible solution to the runway denial problem in Europe. Past efforts to launch aircraft in this manner, including a very successful program conducted by the US Navy to launch the T-2C, F-14, and F-18 aircraft, are reviewed.

An analytical study was conducted for the launch of the F-16, F-15, A-10, A-7D and F-4E from inclined ramps. The takeoff ground roll, stabilizer trim setting, landing gear loads and flight trajectory are reported. The F-15 was selected as a candidate aircraft for a USAF flight test program to be patterned after the Navy program and additional studies were performed. Perturbations in center of gravity, thrust, and ramp exit angle were investigated.

A ramp contour was designed for launch of the F-15, F-16, A-7D and A-10 which minimized the length and height of the ramp while maintaining the landing gear loads below 90 percent of their design limit.

BACKGROUND
1.1 Runway Denial Problem
It has been recognized that the bombing of airbases in Europe could effectively close them to fighter operations for several days. Photographs of airbases that were bombed during the Pakastani war indicate that undamaged segments of the runway will not be large enough for conventional fighter aircraft to takeoff or land. Fighter aircraft require an undamaged strip 50 feet wide and from 2000 to 5000 feet long, depending on the aircraft. The probability that a 5000 foot strip will remain undamaged after an attack is near zero. However, the probability that a 1000 foot strip of undamaged pavement can be located somewhere on the airfield is near a certainty. Therefore, a method of launching aircraft with a ground roll under 1000 feet is a possible solution to the runway denial problem.

The operational concept is to have a moderate number of ramps distributed about the airbase at the ends of taxiways and runways. The number should be large enough so that there is a high probability that several will survive. A post attack damage survey would identify the usable ramps and paths for each aircraft to reach the closest usable ramp. A counter attack could be launched as soon as unexploded ordinance and other debris is cleared from the ramps and selected taxiways.

The ramps could also be used to evacuate an air base in a short period of time in the event of an impending attack. The ramps would provide additional launch sites, many of which would be located closer to the aircraft storage area than the operational runway. This would allow a large number of aircraft to be launched in a short period of time. It would also avoid the vulnerability to attack associated with queuing a large number of aircraft on one or two runways.

Ski-Jump Launch
The use of inclined ramps for launching aircraft has been recognized for some time. A NACA report in 1952 proposed the use of an inclined ramp on aircraft carrier decks to improve the takeoff performance of aircraft (Ref. 1). The ramp proposed in the 1952 report had a radius of curvature of 50 feet and a rise of 1.73 feet. Whereas fighter aircraft launched from a flat deck normally sink as much as 9 feet below the deck, analysis indicated that the addition of a ramp would eliminate the altitude loss.

In 1974 a British Commander wrote his masters thesis on launching the Harrier aircraft from inclined ramps (Ref. 2). This report started an effort that resulted in launch test of the Harrier from enclined ramps in 1977.

About the same time, the US Navy was considering a smaller class of aircraft carriers that would not use steam catapults to launch aircraft. This program generated an analytical effort in 1979 followed by a flight test program to launch the T2C, F-14, and F-18 aircraft from inclined ramps. A metal ramp was constructed that could be modified to give ramp exit angles of 3, 6, and 9 degrees. The ramp was 112.1 feet long and 8.58 feet high at the exit when configured for the 9 degree exit angle, measured from the horizontal. A total of 112 launches of the T-2C, 28 of the F-14, and 91 of the F/A-18 were made. The minimum ground roll for the F/A-18 was 385 feet at a gross weight of 32,800 lbs. This ramp effectively reduced the takeoff roll of the F-18 by more than 50 percent.

Flight Dynamics Directorate Effort
Knowledge of the Navy success in ski-jump launch prompted the Flight Dynamics Directorate to propose the same method of launch for ground based aircraft as a possible solution to the runway denial problem in Europe. Studies were performed to estimate the ski-jump performance of a number of Air Force aircraft.

CONCLUSIONS
1. The F-16 and F-15 are candidate aircraft for ski-jump launch of Air Force aircraft. Reductions in the ground roll of more than 50 percent can be expected.

3. A ski-jump ramp with a 9 degree exit angle, contoured so that the F-16, F-15, and A-7D aircraft at combat gross weights can be launched without exceeding 90 percent of design limit landing-gear loads, will be approximately 180 feet long and 14.4 feet high at the exit.

Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 01 Jun 2010, 20:35
by bjr1028
spazsinbad wrote:madrat, for sure over the years there have been many propositions to vary aircraft ship ops. Here is another one at random, other references not kept during a recent search included crossed runways on a ship for coordinated takeoffs and landings, search the web for a bunch of stuff:

http://books.google.com.au/books?id=PdQ ... &q&f=false


Yeah, if one can think it up, is probably been across someone's desk at Lakehurst. Many options have been looked at. None have shown a credible enough advantage of any changes.

spazsinbad wrote:And to consolidate the (edited) text from the USAF trials (with info about USN experience) of ski jumps - here 'tis....


In the end it was one of ideas that while having benefits was found to be impractical. Besides, anyone with a brain and go after the hangers and parked aircraft or fuel depots rather the runway.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 01 Jun 2010, 21:41
by spazsinbad
bjr1028, nevertheless the ski jump trials were done and information gained.

Before the era of precision guided weapons, either a salvo of dumb bombs rippled at 45 degrees to runway heading to ensure hits or specialised semi precise 'concrete dibber' weapons were used against runways for 'runway denial'. Sure in todays world precision guided weapons make targeting a runway obsolete perhaps.

[EDIT] Always useful to deny runways (and not just one) to enemy aircraft airborne - then where do they go - even if they can take off with a ski jump. Aaahhh this is where carrier aviation is most useful and of course let us not forget STOVL unless the conventional aircraft can not only take off from a ski jump from a damaged/unusable runway but also land back on the ski jump in reverse. Geez I'd like to see that. :twisted: :roll: :D :lol:

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 11:01
by spazsinbad
Just following on from 'madrat' statement: 'It's not like the B model is going to use its lift fan on a ski jump.' Went looking for a video with first effort not clear on this point. Clearly in this X-35B video clip (despite the heading) we can see a short takeoff being performed - shown side on to aircraft:

http://www.youtube.com/watch?v=Dz5I8o9k6Xg

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 15:31
by madrat
I like this concept of using landing gear doors as a blast trap on the F-35B and as air strakes on the A and C models. You don't need the extra drag at higher speeds, being deployed when you need them for low speed handling. I wonder if the shaping of the gear housing will help with a ski jump effort.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 16:06
by spazsinbad
md, here is an explanation of some of the magic in the STOVL version which is probably more important:

From Supersonic to Hover: How the F-35 Flies By Chris Kjelgaard 21 December 2007

http://www.space.com/businesstechnology ... works.html

Extra thrust for hovering
But, for hovering, the F-35B can rely on 40,000(+) pounds of thrust without having to use reheat. The F135's full-authority digital engine control (FADEC) software runs the engine at a higher temperature for hover flight than it does during conventional flight, producing more "dry" thrust than the engine normally develops without activating its afterburner.

"We de-rate for CTOL (conventional take-off and landing)" operations, explained Dan Tennant, Pratt & Whitney's F135 system demonstration and development program manager.

When the F-35B is hovering, all 40,000 pounds of thrust is directed downwards, not backwards. It also can be directed anywhere in between, and even slightly forwards, said Tennant.

How the F-35B achieves all this involves a complex fusion of software, precision engineering and materials technology. The F135 is designed to be completely interchangeable with any other F135 or F136 in any of the three versions of the F-35 Lightning II, two of which won't land vertically. However, in the STOVL F-35B, the engine's design also allows for a forward-leading shaft to be coupled to the spool driven by the F135's low-pressure turbine.

The F-35B's lift fan
This spool drives the main fan that pulls air into the engine to allow combustion to take place. But when the spool is coupled (near the main fan) to the shaft, the spool/shaft arrangement also drives a twostage, vertically mounted "lift fan" situated just behind the pilot's cockpit.

In hover mode, the F135's low-pressure spool imparts 28,000 shaft horsepower to the shaft, said Tennant. This is then converted to vertical thrust in a 90-degree gearbox located behind the cockpit. In this gearbox, a clutch engages a horizontally mounted pinion gear on the shaft to drive two vertically mounted bevel gears, one above and one below the pinion gear.

The two bevel gears rotate in opposite directions, each gear driving a short vertical shaft. These shafts power the two counter-rotating fan stages of the lift fan, Tennant explained. Doors in the fuselage above the lift fan open to provide an auxiliary air inlet and the fan forces air downwards to produce 20,000 pounds of vertical thrust. The air exits through a "variable area vane box nozzle" (VAVN) situated in the bottom of the fuselage directly underneath the lift fan.

"It allows us to control (vertical) thrust ... magnitude and direction," said Tennant. The VAVN "looks like a set of Venetian blinds. When it's somewhat closed, thrust can point somewhat aft to somewhat forward, or straight down."

Pitch and roll control while hovering
While the lift fan is providing downward thrust near the front of the aircraft, an amazing assembly called the "three-bearing swivel duct" produces another 20,000 pounds of downward thrust from the engine's exhaust at the rear of the aircraft, and controls the aircraft's pitch attitude.

The swivel duct is composed of several attached, overlapping pieces that swivel at angles to each other with the aid of ball bearings. It can direct the engine's exhaust air anywhere in a 105-degree continuous range from straight back through directly down to slightly forward, said Tennant. Pointed downwards, the duct looks like a stubby elephant's trunk.

When hovering, the F-35B also relies on two "roll post ducts," downward-pointing nozzles located in the root of each wing.

The F135 is a low-bypass turbofan engine: Some of the air pulled in by the fan at the front doesn't go into the engine core to be mixed with fuel and burned, but bypasses it to flow outside the casing.

During hover, some bypass air is directed into the roll post ducts to give the F-35B roll control stability while performing a vertical take-off or landing. (Although the F-35B needs a short take-off run when fully loaded, it produces enough vertical thrust to take off vertically when lightly loaded.)

FADEC software varies the thrust through each roll post duct independently to ensure the pilot has complete roll control over the aircraft while hovering, said Tennant.

Four FADEC systems
In its F-35B partnerships, Rolls-Royce is responsible for the lift fan and its associated drive shafts, gearbox and clutch, as well as the swivel duct and the roll post ducts. In the F135-equipped F-35B, Pratt & Whitney provides the engine itself, its stealth-optimized exhaust nozzle and, most importantly, the FADEC software.

Uniquely, the F-35 features not one but four FADEC systems -- two for the main engine, to ensure complete redundancy of operation, and, likewise, two for the lift-fan system.

"The software is a big piece of the technology that makes the STOVL work," said Tennant.

The FADEC software is so complex that it runs through a high-speed databus that P&W developed specifically for the F-35's propulsion system. This databus is linked by means of a firewire-like system to the high-speed databus developed by Lockheed Martin to control the aircraft's other systems.

RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 16:16
by spazsinbad
And from recent pilot experience here is some more (worth reading all of it):

Piloting the Joint Strike Fighter

"Testing of the Lockheed Martin F-35 Lightning II (joint strike fighter) is well underway. Ian McInnes catches up with Graham "GT" Tomlinson, BAE Systems' lead test pilot for the STOVL variant, to find out how it flies. Date: 26 May 2010

http://www.airforce-technology.com/feat ... ture85998/

"All STOVL aircraft encounter non-linear behaviour close to the ground, caused by hot air bouncing back up and interfering with aerodynamics and propulsion characteristics. I'm greatly encouraged that our experiences of this so far have been as good as we could have hoped; it is far more benign than in the Harrier family. It will undoubtedly remain an area of interest as we expand the wind envelopes for low speed take-offs and landings.
&
It also surprised me that the aircraft copes so well with the airflow disturbances created by the huge door above the lift fan, which generates destabilising airflow for the rudders and tails. The upside of the door is that it scoops flow into the lift fan intake and adds significant thrust. The downside is the non-linear flow over the rear of the aircraft at conventional speeds where we convert from a conventional aircraft into a STOVL aircraft. The compromise seems to have been made just about right, as we retain satisfactory control through the conversion process (opening the doors and spinning up the lift fan). This will be another area of interest as we expand the
conversion window from our initial heart-of-the envelope speeds.
&
It is when you sit back afterwards that you realise what fun it is, how lucky we are as individuals to be involved at this early stage of testing and how the UK's heritage of STOVL aircraft has propelled us to the forefront of testing of this latest incarnation."

Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 16:51
by bjr1028
spazsinbad wrote:bjr1028, nevertheless the ski jump trials were done and information gained.

Before the era of precision guided weapons, either a salvo of dumb bombs rippled at 45 degrees to runway heading to ensure hits or specialised semi precise 'concrete dibber' weapons were used against runways for 'runway denial'. Sure in todays world precision guided weapons make targeting a runway obsolete perhaps.

[EDIT] Always useful to deny runways (and not just one) to enemy aircraft airborne - then where do they go - even if they can take off with a ski jump. Aaahhh this is where carrier aviation is most useful and of course let us not forget STOVL unless the conventional aircraft can not only take off from a ski jump from a damaged/unusable runway but also land back on the ski jump in reverse. Geez I'd like to see that. :twisted: :roll: :D :lol:


Runway denial isn't very effective. Repairing the runways are too easy.

RE: Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 02 Jun 2010, 21:50
by spazsinbad
bjr1028, I'm not interested in land base use of ski jumps but shipboard use. Without actually getting the USN to install a ski jump on a ship the only way to test them in the US to date has been land based. And they are effective as illustrated.

RE: Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 04 Jun 2010, 03:54
by spazsinbad
Quote about 'short takeoff performance' fully combat loaded (but no mention of wind strength or ambient temperature which always have an effect on takeoff performance for any aircraft): "Tomlinson said that a fully combat loaded F-35B will take-off from a small unimproved airstrip in less than 1200ft." This is where point a ship into wind to get a good WOD helps heaps.

http://www.examiner.com/x-5411-Military ... st-fighter

RE: Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 14 Jun 2010, 23:05
by spazsinbad
X-35B Mission X pilot (then) Major Tomassetti describes a short takeoff:

http://www.airspacemag.com/military-avi ... ion_X.html

"Once in position for takeoff I moved the Thrust Vector Lever (TVL) back about an inch, initiating the process of converting the aircraft from CTOL mode to STOVL. Behind the cockpit, four sets of doors were opening. This would allow air to flow through the lift fan and enable the vectoring rear nozzle to move through its full range of travel. While the doors were opening, the clutch was engaging, transferring power from the engine to the lift fan. The only noticeable change in the cockpit was an increase in noise as the lift fan spooled up."
&
"...at 80 knots, after only 200 feet, I vectored the thrust to 60 degrees and the aircraft leapt off the ground. I completed the post-takeoff checks, climbed through 5,000 feet, and converted the aircraft from STOVL mode back to CTOL ..."

RE: Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 19 Jun 2010, 09:47
by spazsinbad
3rd video in an illustrated list (below main screen on page - OR - click on the 3rd text link on right ) shows an:
F-35B Short Take Off test:

http://article.wn.com/view/2010/06/15/F ... h_fighter/

"F-35B JSF Short Take­off Test" 0:35 seconds. Note rotated rear nozzle from beginning.

RE: Re: RE: Re: RE: Re: F-35B/C and the Ski-Jump???

Unread postPosted: 27 Jul 2010, 02:01
by spazsinbad
Lockheed Martin rebuts F-35 critics on cost, progress By: Chris Pocock July 19, 2010

http://www.ainonline.com/news/single-ne ... ess-25359/

"...The first F-35B arrived last November, and by early January began testing of the conversion from wingborne to jetborne flight, following rigorous testing over a hover pit.

“We built down in small steps,” said Tomlinson, “starting with increasingly slower landings before progressing to vertical landings and short takeoffs.” The first fully vertical landing was made on March 18.

When asked how the F-35B compared to the Harrier in terms of ease of takeoff/landing, Tomlinson replied: “It’s chalk and cheese–and so it should be! This is a single-button operation with no special controls–much easier than the Harrier. For short takeoffs you just power up; the system takes care of everything else. On the ski-jump, for instance, the system detects the change in deck angle and doesn’t apply any rotation as it would on a flat deck.”

The recent arrival of F-35 BF-4 is a milestone, as this is the first aircraft equipped with a mission system, including the APG-81 AESA radar. The first three F-35Bs are aerodynamic/aircraft systems testbeds, with BF-1 bearing the brunt of STOVL trials, and BF-2 handling speed/ load testing. It was this aircraft that achieved Mach 1.07 last June.

Testing has revealed a few minor problems. Some work was necessary to “tweak” the tail controls for optimum effect in the disturbed air caused by raising the forward lift fan door. Generally the team is ahead of schedule, and completed 155 flights against a planned 107 last year.

Trials with a ski-jump are expected to begin by the end of next year, the ramp having been built in the UK for installation at Patuxent River. This will be a crucial step for the F-35Bs destined for the Royal Navy. Perhaps more challenging from a testing standpoint will be the trials of short takeoffs from the flat-deck “Wasp” class LHDs from which the F-35B will operate in U.S. Marine Corps service.–David Donald"

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 08 Feb 2014, 05:08
by spazsinbad
FWIW GoogleErf has an updated overhead of NAS Patuxent River dated 20 Oct 2013 so I'll post a few pics for posterierority. :doh: CLICK on the thumbnails pics to see more detailed BIG pic..... SCALE on Pics also....

SKI JUMP YELLOW LINE DISTANCE is 908 feet from what I guess is the start after the Square with 'H' on it from right to left.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 08 Feb 2014, 06:38
by spazsinbad
Allowing for being able to line up under own power etc. the approx. take off distance from stern to end of ski jump will be 850 feet on CVF. BIG PIC: http://farm8.staticflickr.com/7369/9929 ... 94ae_o.png

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 14 Feb 2014, 08:20
by spazsinbad
This LM promo fillum from recent Singapore Air Show shows the centrefield at PAXriver with an F-35B nose. Screenshot to follow....

Aeronautics in the Asia-Pacific Region 13 Feb 2014
"Why is the Asia-Pacific region so important to Lockheed Martin? George Standridge, Vice President, Lockheed Martin Aeronautics Business Development, talks about aeronautic capabilities and partnerships locally and worldwide."


Re: F-35B/C and the Ski-Jump?

Unread postPosted: 13 Apr 2014, 09:39
by spazsinbad
Interesting factoid about hi speed data buses for the FADECs about midway up the page.
"...The [F-35B] FADEC software is so complex that it runs through a high-speed databus that P&W developed specifically for the F-35's propulsion system. This databus is linked by means of a firewire-like system to the high-speed databus developed by Lockheed Martin to control the aircraft's other systems."

Anyway here is something relevant to JUMPdeSKIs from CVFs anyways - from a chap who should know - but may not if he is a CRAB! :devil:

And for something completely different - another factoid about the thread topic title question?

ETS winter 2012_13 LIGHTNING STRIKES

"...Onboard the Queen Elizabeth aircraft carriers, the aircraft would take off at its maximum weight of nearly 27 tonnes using a UK-developed ski-jump, and land either vertically or using the novel UK-developed Short Rolling Vertical Landing [SRVL) technique. This would enable the jet to land at a much higher weight than is possible in a purely vertical Landing.

[2204.62lbs = 1 tonne | 59,535lbs = 27 tonnes] (F-35B is in the 60K weight class)

Wing Commander Hackett explained: "SRVL is under development for the carriers. but it means the aircraft would fly in at around 60 to 70 mph and then brake to a stop on the deck, without the need for any costly arrester gear. It will be able to land up to 1.8 tonnes (4,000lbs [3968.32072 pounds]) heavier than would otherwise be possible, meaning unexpended weapons can be brought back to the ship."

SOURCE: http://content.yudu.com/A219ee/ETSWin12 ... ces/20.htm

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 22 May 2014, 20:07
by zerion
Pax readies F-35B ski jump

http://www.dcmilitary.com/article/20140 ... i-launches

By Sarah Ehman

Atlantic Test Ranges Business Communications

Thanks to a partnership between the Atlantic Test Ranges (ATR) and the F-35 Lightning II Pax River Integrated Test Force (ITF), the Joint Strike Fighter took one step closer this Spring to making its debut on international ships.

The Pax River ITF partnered with ATR’s Geomatics and Metrology team to perform a high fidelity survey of the shore-based ski jump at Naval Air Station Patuxent River’s center airfield. The survey is a prerequisite to future F-35B flight testing by the Pax River ITF, the United Kingdom and Italy.

The shore-based ski jump at centerfield was built in the United Kingdom, divided into sections, then transported and reassembled at Pax River.

“Launching off our Pax ski-jump paves the way to F-35Bs launching off our international partner ships that feature ski-jumps,” said Bob Nantz, the Pax River F-35 ITF external environment and performance lead. “The significance of the Pax ski-jump shape is connected to aircraft loads and performance modeling. Ideally, the loads will never limit the launch weight or speed, thus allowing the maximum performance benefit.”

Together, Fred Hancock, Sung Han and Warren Kerr, each with ATR Geomatics and Metrology, employed electronic differential leveling and total station measurement techniques to check for drift in construction and determine precise deviations in both vertical and horizontal components of the ramp.

“We captured hundreds of elevation readings, determining the relative vertical difference between points,” Hancock said. “We also obtained precise angular distance measurements to determine if the ramp edges were parallel to the center line. This helped us to know whether the ramp was at all skewed.”

Hancock noted that the team achieved readings accurate to within one millimeter — approximately the thickness of a credit card.

“The razor-sharp accuracy of the Geomatics team’s survey is a key part of the process leading to future ski-jump operations at sea,” Nantz said.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 22 May 2014, 20:18
by spazsinbad
Thanks 'zerion' I'll add the photo...
“U.S. Navy photo/Jennifer Amber The Atlantic Test Ranges Geomatics and Metrology team, from left, Fred Hancock, Sung Han and Warren Kerr survey the ski jump ramp that was assembled at Naval Air Station Patuxent River in 2009 to document potential deviations from the original design plan.”

Source: http://www.dcmilitary.com/storyimage/DC ... 529960.jpg


Ski Jump Pax River Survey May 2014 AR-140529960.jpg

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 14:39
by spazsinbad
Back in olden tymes the Harrier Ski Jumping was big news and here it is at Farnborough 1978 (clip from http://www.youtube.com/watch?v=PGrIrxpv62U in an earlier post by 'quicksilver': viewtopic.php?f=22&t=15455&p=272150&hilit=jump#p272150 )


Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 19:00
by SpudmanWP
The video is "private"

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 22:03
by spazsinbad
Youtube has shitted me since day one. I have no idea why the video was set on 'private'. I did not do that nor is it the default setting. The video should not be 'private' now. I'll upload the .WMV here now. BTW some Brits you could just hit with a filthy big RUBBER HAMMER - this guy is one of 'em. "One of the most spectacular Farnborough Shows never took place"? :devil: (Some aircraft I guess a specially built aerobatic number was going to land and takeoff from the ski jump.)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 22:30
by SpudmanWP
That mole... I could not stop looking at it :)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 23:19
by popcorn
SpudmanWP wrote:That mole... I could not stop looking at it :)

LOL.. reminded me of a scene from an Austin Powers movie..

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2014, 23:44
by spazsinbad
:twisted: :devil: which mole? :mrgreen: :doh:

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 11 Jul 2014, 18:49
by spazsinbad
Somehow I missed this thread earlier for Jump De SKY - so I'll post that info here also and keep this thread in mind for any additional SKI JUMP / SKI-JUMP info (the 'Ski-Jump' probably defeated my earlier search - oh well). So from:
viewtopic.php?f=22&t=20304&p=275046&hilit=Jump#p275046

...here is one piece of info I overlooked, being reminded recently by the inestimable 'Engines' over on pPrune (who may have been the engineer responsible for this innovation - only my guess) for STOing off the SKY JUMP. I have not seen the Uhmericans mention this feature - it seems from my reading that the roll control doors are closed when not needed with the air being blocked by them. http://www.pprune.org/military-aircrew/ ... ost8450458 Anyway....
CVF ski-jump ramp profile optimisation for F-35B
A. Fry, R. Cook and N. Revill, FEBRUARY 2009 VOLUME 113 NO 1140

"...1.4 F-35B STOVL lift and propulsion system
The F-35B has a number of unique elements that facilitate its STOVL capability, and these are critical in the optimisation of a ski jump ramp profile for the aircraft. A basic description of the layout and function of the lift and propulsion system... described below:

● a Lift Fan driven by a shaft from the main engine which provides vertical lift through a variable area vane box nozzle using louvered vanes to vector thrust between vertically downwards and partially aft.

● a three-bearing swivel module (3BSM), which vectors the main engine exhaust thrust from the core engine through vertically downwards to fully aft – the latter being the default for conventional mode flying.

● roll nozzles, ducted from the engine and exiting in each wing providing roll control and vertical lift. These are closed off during the initial portion of the short take-off (STO) in order to maximise forward thrust from the main engine, opening towards the end of the ramp in order to provide control and lift during the fly out...."

Source: http://www.raes.org.uk/pdfs/3324_COLOUR.pdf [not available now]

And repeated earlier here [ viewtopic.php?f=56&t=25691&p=274461&hilit=post#p274461 ] but posted again here due relevance...
Powering the Lightning II
April 2012 Chris Kjelgaard

"...According to Jones, the roll posts themselves are variable-area nozzles which are situated in the lower part of each inner wing section and act to provide roll control for the F-35B while it is in hover mode. In order to do this, the roll-post ducts direct bypass air from the engine to the roll posts, which drive the air out through the bottom of each wing. In the F-35B, 3,700lb (16.46kN) of thrust in the form of bypass air is directed out to the two roll posts while hovering.

Each roll-post assembly features a pair of flap-type doors in the bottom of the wing, controlled by the FADEC. Jones says these titanium doors are controlled by rotary actuators which allow fully variable opening, providing a degree of thrust variability and directionality so that the pilot can control roll while hovering. He says Lockheed Martin’s original X-35 concept demonstrator featured doors between the engine casing and the roll-post ducts which could be closed when the aircraft was not hovering, but in production aircraft there are no such doors and bypass airflow is constantly sent to the ducts. The only way to control roll-post thrust is via the flap-doors in the bottom of the wing...."

Source: http://militaryrussia.ru/forum/download ... p?id=28256 (PDF 14Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 21 Aug 2014, 06:48
by spazsinbad
Difficult to answer all those questions concatenated such as they are and as I'm not concerned by the 'other' ski jumpers you mention, the RN CVF ski jump is relevant to the F-35B so here is the news: (repeat from elsewhere on forum)

This is a good ski jump page: viewtopic.php?f=58&t=15969&p=274869&hilit=Hackett#p274869
&
OMG here on this thread: viewtopic.php?f=22&t=14082&p=269627&hilit=Hackett#p269627
ETS winter 2012_13 LIGHTNING STRIKES

“...Onboard the Queen Elizabeth aircraft carriers, the aircraft would take off at its maximum weight of nearly 27 tonnes using a UK-developed ski-jump, and land either vertically or using the novel UK-developed Short Rolling Vertical Landing [SRVL) technique. This would enable the jet to land at a much higher weight than is possible in a purely vertical Landing. [2204.62lbs = 1 tonne | 59,535lbs = 27 tonnes] (F-35B is in the 60K weight class) Wing Commander Hackett explained: "SRVL is under development for the carriers. but it means the aircraft would fly in at around 60 to 70 mph and then brake to a stop on the deck,.... It will be able to land up to 1.8 tonnes (4,000lbs [3968.32072 pounds]) heavier than would otherwise be possible, meaning unexpended weapons can be brought back to the ship.”

Source: http://content.yudu.com/A219ee/ETSWin12 ... ces/20.htm

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 21 Aug 2014, 10:48
by popcorn
spazsinbad wrote::twisted: :devil: which mole? :mrgreen: :doh:



Re: F-35B/C and the Ski-Jump?

Unread postPosted: 28 Aug 2014, 21:50
by spazsinbad
Belated thanks to mods for fixing the 'FLASH PLAYER' malware issue seen above and now for something completely different.... The single page PDF attached has some low quality photos of the various USN aircraft on the SKI JUMP. The RAN LHD Ski Jump is not such an issue with deck markings showing a helo spot at the beginning of the ramp up. Art Nalls USMC has said as much in his treatise on potential ski jumps for USMC flat decks (search forum for Nalls). Go here:

viewtopic.php?f=22&t=12631&p=233379&hilit=Nalls#p233379
&
viewtopic.php?f=22&t=12631&p=230276&hilit=Nalls#p230276
The Kneeboard
Winter 2014 Patuxent River Naval Air Museum Association

"Run & Jump!
Aircraft ski jumps interested the military for two reasons. The Air Force and Marines wanted a way for aircraft to operate from the short stretches of runway remaining after airfield bombing attacks. The Navy and Marines wanted a way to reduce the length of carrier flight deck needed for an aircraft to become airborne—without the aid of a catapult. The Air Force decided not to use ski jumps, but the Navy proceeded with the idea. During the late 1970s and early 1980s, the Naval Air Test Center (NATC) performed ski jump tests at NAS Patuxent River using the T-2, F-14, F/A-18, and AV-8 Harrier.

However, the ski-jump design has drawbacks: the forward part of the flight deck is no longer available for parking aircraft and there is less space available for moving aircraft around on the already crowded carrier deck. In addition, the upward push of the ski jump also means that aircraft structures may need to be stronger to bear the extra launch loads. This could lead to aircraft that weigh—and cost—more.

Flight tests showed that the basic theory was sound: all aircraft tested took off in significantly shorter distances than they could from flat decks. But except for the AV-8 Harrier, none of these aircraft ever flew from ski-jump-equipped carriers.

The F-35B VSTOL (Vertical/Short Take-Off & Landing) version of the Lightning II Joint Strike Fighter (JSF) will soon take its turn on a new ski jump at NAS Patuxent River. These tests will support the Marine Corps and JSF partner nations Great Britain and Italy, which operate carriers designed with ski jumps."

Source: http://api.ning.com/files/xEh6B1KdSWQzO ... educed.pdf (1Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Sep 2014, 09:55
by spazsinbad
Stepping-Stones
Tony Osborne AVIATION WEEK & SPACE TECHNOLOGY / SEPTEMBER 8, 2014

"...Particular emphasis has also been placed on how the F-35 will launch from the Queen Elizabeth's ski jump, which gives the aircraft valuable vertical impetus, allowing for greater takeoff weights as well as a positive rate of climb. The F-35B's flight control logic has been written for the Queen Elizabeth's new 12-deg. jump, which at 200 ft. long, is some 50 ft. longer than that used on the Invincible-class carriers.

With the aircraft lined up for takeoff, the pilot presses the short-takeoff-and-vertical- landing (STOVL) switch, activating the lift fan and rear nozzle. The lift fan is fully operational within 15 sec. The F-35B uses the same process and partially opens its weapons bay doors, which help provide more lift. As the aircraft hits the ski jump, its flight control logic recognizes it is on the ski jump and uses the rear nozzle to keep all three wheels on the ground. The aircraft should be airborne at around 90 kt.

"It's a luxurious way to get airborne,'' says Wilson. "The pilot simply uses the pedals to keep the aircraft straight, and the aircraft recognizes the presence of the ski jump." Test pilots have tried out the ski jump only in the simulator, but that work has been very valuable in addressing early concerns about the ground clearance between the ski jump and rear nozzle...."

Source: AVIATION WEEK & SPACE TECHNOLOGY / SEPTEMBER 8, 2014

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 26 Sep 2014, 17:49
by spazsinbad
Not strictly about SRVL with general info about QE simulator with take off stats (from the Jump De Sky) at end.
Ship Shape F-35/QEC simulator
SEPTEMBER 2014 AEROSPACETESTINGINTERNATIONAL.COM; PAUL E EDEN

"...HARRIER LEGACY
Comparisons are frequently made between the F-35B and the Harrier; they are usually misleading. But in the case of BAE Systems’ F-35/carrier flight simulator, earlier work with the legacy jet and Invincible class ships has helped lay the foundations for Warton’s 21st century simulator design. As David Atkinson, F-35 Carrier Integration Lead at BAE Systems, explains, the result is a flexible system with capabilities beyond F-35B: “We’ve been conducting flight simulation at Warton for over 50 years for many projects, including simulating Harriers operating from the recently retired Invincible CVS class. The F-35/carrier flight simulator has been developed to support the integration of the F-35 to the QE class ships. It is, however, capable of simulating F-35C to aircraft carriers with catapults and arrestor gear, and has been used for assessment of various flight control developments for F-35C to CVN and, while the UK was considering a CV-converted QE class ship, for F-35C to QE.”

Unlike the more familiar full mission simulator, the F-35/carrier sim focuses on the near-ship environment, primarily for the assessment of launch and recovery operations, including circuits around the ship. It uses a Lockheed Martin F-35 six-degrees-of-freedom mathematical model validated against extensive flight test data; a QEC ship motion model provided by the Aircraft Carrier Alliance (ACA), based on tank test data; and a computational fluid dynamics (CFD) ship-airwake flowfield that is being further developed and validated by the University of Liverpool.

Realism has been further enhanced by the recent addition of a landing signal officer’s (LSO) station. The LSO’s role will be similar to that aboard an Invincible class ship, but according to Atkinson there will be “a larger workstation and more sophisticated situational awareness aids and information displays”.

Describing the simulator’s design and how the LSO station is integrated, Atkinson continues: “From a physical point of view it has a hydraulic motion platform within a dome and uses motion-cueing algorithms to enable the pilot to feel aircraft motion in a very realistic way, despite remaining very firmly on the ground. High-specification projectors are used, with a very high-resolution projector for the pilot’s forward field of view. It has a second projected screen display to represent part of the FLYCO – the LSO workstation, at which a pilot can operate as an LSO, interacting with the pilot flying the simulator, while watching the aircraft maneuver in real time. The combined motion simulator and FLYCO representation have proved very valuable while developing maneuvers, operating procedures and display layouts.”

SIMULATOR AMBITION
Allowing pilots to fly F-35B approaches in cooperation with an LSO, as they will on the real carrier at sea, is already delivering immense value to the program, but Atkinson says that the simulator is scheduled for much greater capability. “Our ambition is for the simulator to be used for wider purposes than pilot and LSO interactions...."...

...Work to date has driven modification and refinement in carrier flight deck design, aircraft design and operational procedures. “We’ve conducted a number of trials to develop the F-35B to QEC vertical landing, ski-jump launch and shipborne rolling vertical landing maneuvers and the supporting systems; visual landing aids (flight deck lights, glidepath indicators), F-35B helmet mounted display symbology, LSO situational awareness aids and standard operating procedures.

“We’ve helped the MoD and the ACA optimize and gain confidence in their designs and likewise for some changes we’ve made to the F-35B, to allow shipborne rolling vertical landings to be conducted. These are unique to the QE class and involve a rolling vertical landing onto the ship’s ‘runway’ with 30 to 40kt of overtake, allowing increased bring-back weight performance for the aircraft, which should pay dividends on operations,” says Atkinson....

...Over more than a decade of work, Warton’s F-35/carrier simulator has identified and helped fix various issues, as well as facilitating the safe expansion of the operating envelope. “The QE class has an immense flight deck with state-of-the-art visual landing aids,” says Atkinson. “The F-35 is a hugely capable 5th generation aircraft that pilots find easy to fly to a ship and we believe that there are lots of good ways to operate the F-35B to a ship the size of the QE, with our role being to optimize the designs and procedures to maximize performance. We’ve identified a few issues and concerns through the simulation work, but thankfully it also provides an ideal environment to visualize problems, explain them and rapidly show how potential solutions would work. Between the MoD, ACA and ourselves we have identified and resolved a number of issues over the 10 plus years that we’ve been working together using the Warton simulator.”...

...The potential of Warton’s F-35/carrier simulator to begin the definition of a future training syllabus even as its test work continues is obvious and Atkinson confirms its role, not only in pilot training, but also for flight deck crew: “We have already used the simulator to inform the training syllabuses and help our customers understand the benefits of immersive simulation to their training processes for the pilot and LSO. What is abundantly clear is that simulation technology is here to stay and continues to increase its role in development and training based on cost-effectiveness and an ever-increasing ability to emulate the real world.”

300 Take-off run in feet from QEC for lightly loaded F-35B

800 Take-off run in feet[/b] from QEC for[/b] fully loaded F-35B

Source: AEROSPACE TESTING INTERNATIONAL September 2014

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 11 Oct 2014, 04:35
by spazsinbad
News about Indian NEW CARRIER Ski Jump at 14 degrees....
India's 1st indigenous aircraft carrier taking shape at Kochi
09 Oct 2014 Press Trust of India | Chennai

“India's first indigenous aircraft carrier was taking shape in the Cochin Shipyard Limited at Kochi, one of the nine Defence PSUs in the country, where 85 per cent of the work relating to its hull are complete, a senior official said here today.

"Around 85 per cent of the hull is complete and 90 per cent of the fabrication is over. 85 per cent of the erection has been over," Commodore K Subramaniam (Retd), CSL Chairman and Managing Director told reporters on the sidelines of a function organised by the CII.

Interacting with journalists in the sidelines of a CII- organised conference on 'Approach to Integrated Maritime Systems' here, he said many elements of innovations were being incorporated in the building of the aircraft carrier.

"For instance, the Navy wanted a 14 degree ski-jump in the foxle [foc'sle=forecastle or FRONT END] of the ship for easy taking off of fighter planes, for which a big piece of iron had to be welded, which was also trimming down the ship to the front.

"We have employed a big piece of iron in the hull area, which will function as a buoyant, which has made the keel of the hull float horizontally. Likewise, we have made many innovations in the building."

Replying to a query, he said the degree of indigenous equipment in the aircraft carrier was very high, barring the aviation, for which the county was dependent on Russia. "We can say around 80 per cent of the ship is indigenous."...."

Source: http://www.business-standard.com/articl ... 936_1.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 28 Jan 2015, 11:23
by simon257
Has their been any news on Flight Testing the F-35B and the CVF Test Ski-Jump yet? I was under the impression it was due to start last Autumn.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 28 Jan 2015, 11:44
by spazsinbad
Yes that would be true if true and I have no doubt (except for the detail) and I look for news of this event and any SRVL related event - but no joy - regularly. I'll guess as we have seen in many news items to date that the USMC IOC 2B software and related testing has occupied the minds of the F-35Bers (with the delays we all know and love - engine or not related). For sure if you find any news please let us know. You can see on other threads that 'slow landings and expeditionary ops' have been tested to some degree but as we all know by now a SKI JUMP is a small thing in the overall scheme of things - but I jest.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 28 Jan 2015, 12:54
by simon257
Thanks for the reply. I would have thought that the RAF/RN side of the Test team, would have been taking the lead on this aspect of the programme. Seeing as the Ski-Jump is a UK specific requirement.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 30 Jan 2015, 21:25
by quicksilver
Deleted. Wrong thread. :doh:

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 02 Feb 2015, 04:38
by spazsinbad
Just to keep us interested here are the Italians doing their thang: and a false canapé?
Pure adrenaline through the eyes of a pilot harrier Navy
Published on Jan 26 , 2015 Marina Militare

"A minute of pure adrenaline through the eyes of a pilot of the Navy. What are you waiting for? Become a Navy officer."


Re: F-35B/C and the Ski-Jump?

Unread postPosted: 14 Feb 2015, 01:16
by spazsinbad
Thought this is a good spot (possie/pozzie = position in OzSlang) for this tidbit 'bout the LCA NAVY performance. Sadly the WEIGHT not mentioned but what can we expect - the full NATOPS? No. Anyway it is a start for a comparison for performance perhaps. And I'll shut up now. Probably the UPengined Version to be developed will greatly improve the distance / take off weight scenario. Already this 2nd prototype is performing better than expected on the ski jump but performance was projected to be in the 'hopeless' category a few years ago. Another thread with LCA Navy info has that info.
A Turnaround For India’s First Indigenous Fighter
13 Feb 2014 Jay Menon | Aviation Week & Space Technology

"...The ski-jump test last December showed the aircraft can get airborne from the carrier deck within 200 meters (660 ft.), compared with 1,000 meters for a conventional runway takeoff. LCA-Navy is heavier than the air force version and has a fuel-dump capability to reduce weight for arrested landings.

“The LCA-Navy is designed with stronger landing gear to absorb forces exerted by the ski-jump ramp during takeoff,” says K. Tamilmani, chief controller of aeronautics R&D at India’s Defense Research & Development Organization. A special flight-control law allows hands-free takeoff from the ramp, reducing pilot workload and automatically putting the aircraft on a climbing trajectory. A second phase of SBTF tests will involve arrested landings, he says.

At 8.5 tons, the Tejas is light for a single-engine multirole supersonic fighter, but it is heavier and lower performing than planned. So development has begun on the larger Mk. 2, with a more powerful General Electric F414/INS6 engine in place of the Mk. 1’s GE F404/INS20. GE Aviation says it will begin delivering F414s to India next year, with first flight of the Tejas Mk. 2 expected in 2017."

Source: http://aviationweek.com/Tejas

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 14 Feb 2015, 03:45
by sferrin
They've been working on that thing forever.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 14 Feb 2015, 23:37
by spazsinbad
Working on something forever? Sound familiar? Anyway here is a pic with link to more TEJAS (NavyWise) FOREVER info. Note the very different OLS (Optical Landing System) plus CHOCKS for the 'before ski jump windup' (ala Ruskie method).

The 'restraint system' (chocks wot go up and down) are 200 metres from the ski jump BTW.

https://www.scribd.com/document_downloa ... ension=pdf (42.5Mb)

BTW this 28 page PDF is way too large for use online (probably made for printing but... whatever...)

Then there is a DRDO brochure with a bunch o' good stuff with another graphic of the OLS:

https://www.scribd.com/doc/255722941/DRDO-Brochure-2015 (39Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 15 Feb 2015, 02:13
by spazsinbad
'sferrin' said above: "They've been working on that thing forever." An Answer Below: This is a long article so worthwhile to download if interested with some good graphics included. I have a query about a 'normal' landing - probably an editing error. [Have looked at the F-35 again to see that it has a 21/2 times the capacity of CEE v AAA - so I'll put that lot down below.] Anyway some of the tribulations overcome to make an AirForce Aircraft into a NavAver...
Former CNS Admiral Arun Prakash writes on
The LCA-NAVY | IS IT READY FOR SEA?
Vayu IV/2012

"The long-awaited maiden flight of the LCA-Navy prototype (NP-1) took place on 27 April 2012, from HAL Airport Bangalore (see Vayu III/2012). NP-1, with the Chief Test Pilot of the National Flight Test Centre, Navy Commodore J A Maolankar at the controls, undertook a successful 20 minutes flight....

...The Problem Areas
It is common knowledge that fighters such as the F-4 Phantom, A-4 Skyhawk, F-18 Hornet and Rafale M, conceived for carrier operations, have been adapted without any problem for shore-based operations. The reverse, however, is not true and an aircraft designed to land and take-off from a 10,000 foot runway, must undergo major modifications before it can operate from a ship’s pitching and rolling 800 foot flight-deck.

Sure enough, the Project Definition study undertaken by the Aeronautical Development Agency (ADA), with help from TsAGI, the Russian Central Aerodynamic Research Institute indicated a number of critical areas which would need to be addressed before the LCA Navy project could be declared a feasible proposition:

- The rate of descent involved in a (no flare) carrier landing being almost twice [?] that of a flared touch down ashore, would require a much stronger landing gear.

- The designed landing speed of the aircraft was too high for the ship’s arrester gear to handle.

- A hydraulically-operated tail-hook would need to be mounted in the belly to engage the ship’s arrester wires and bring the aircraft to a stop in about 250 feet. This would require the belly mounting to be strengthened to withstand sudden deceleration forces.

- The relatively low approach speed required for a carrier landing would necessitate this delta-wing to fly at high angles of attack leading to reduced forward visibility. It would be necessary to restore visibility so that the pilot could make an accurate deck landing.

- With the available engine thrust, it was computed that the aircraft would attain a safe height of about 150-200 feet on exit from the ski-jump. The speed of 120-130 knots would, however, be just marginal to retain aerodynamic control while the aircraft accelerated, and there were doubts about controllability during this transition phase. (The Sea Harrier, too, exits the ski-jump at substall speeds but control is retained by use of reaction controls powered by engine exhaust.)

Undaunted by the scale of technological challenges posed by these observations the relatively inexperienced ADA team expressed confidence that it could find ways to deal with each of the hurdles and produce a prototype LCA-Navy. The IN, true to its word, re-affirmed its faith in ADA and the programme by producing a set of Naval Staff Qualitative Requirements and initiating a jointly-funded engineering development programme in 2003 with a contribution of over Rs. 400 crores. It also found scarce aeronautical engineers and test pilots to help manage the project.

Pains of Transformation
Bringing to bear all their ingenuity and initiative, the LCA-Navy team commenced the process of ‘navalising’ the IAF Tejas for shipborne operations. The first step was a new undercarriage, designed with Russian help, to withstand a vertical rate of descent of 7.5 metres/second, as opposed to 3.1 metres/second for the land-based version. A little-used aerodynamic device, known as leading-edge vortex controller or LEVCON, was incorporated in the wings for improving low speed handling and reducing the landing speed. A tail hook was designed for fitment on a suitable Model of the SBTF, with LCA ‘tailhooked’.reinforced under-belly fuselage mount. The ‘drooped’ nose design of the IAF trainer version was adopted for the LCA-Navy to improve over-the-nose visibility on carrier approach. Repeated computer simulations gave the team enhanced confidence that the transient post-ski jump instability could be countered by some extra engine thrust and changes in the fly-by-wire (FBW) software.

Two unforeseen but avoidable factors have impacted adversely on the LCA development and could well jeopardise the programme unless some early and resolute remedial measures are initiated. Firstly, the basic aircraft having overshot its design weight, the addition of a heavier landing gear, a tail-hook and associated reinforcements has aggravated the weight problem considerably in the case of LCA-Navy. Secondly, the indigenous Kaveri engine having failed to meet development milestones, the project has had to fall back on the General Electric F-404-IN-20 afterburning turbofan, and 40 have recently been contracted for the Tejas.

The F-404 is said to barely deliver the thrust necessary to meet IAF performance requirements. The heavier LCA-Navy, during many phases of carrier operations, especially ski-jump launch or a late go-around on approach, will be operating at the limits of its envelope where lack of engine thrust would be a debilitating handicap. Further, the air-intake design of the Tejas is optimised for high mach-numbers and tends to ‘starve’ the engine of air at low speeds, which could aggravate the thrust-deficiency for a ski-jump launch. Reducing payloads to maintain safety margins will result in performance penalties unacceptable to the Services. Unless the Kaveri project can be salvaged with foreign assistance, a better engine will have to be identified to power the LCA-Navy and the search should have started yesterday!

Challenges Ahead
As the LCA-Navy flight-test team embarks on the unique venture of qualifying an unstable, FBW, delta-wing prototype for STOBAR operations, the road ahead programme promises to be exciting - but complex. The current plans call for a second prototype, a single-seat fighter, to join NP-1 as technology demonstrators for undertaking ski-jump and deck-landing trials as well as weapons integration and carrier certification.

It appears that the undercarriage, described by the Chief Test Pilot as akin to “a WWF wrestler”, as well as the tail-hook, have been over-designed and are excessively bulky. This may be understandable as a measure of caution, but it is also surprising because the Russians, who provided such advice, had recent experience of designing undercarriages and hooks for a number of their own carrier-capable aircraft types. It will, therefore, be necessary on successful completion of trials, to re-design an optimal undercarriage and hook for fitment on subsequent aircraft. With more engine power, weight reduction measures and other improvements, this will become the LCA-Navy Mk II.

Although the availability of test-rigs, telemetry and a simulator in ADA have taken a lot of toil and suspense out of flight-testing, there are many segments of the performance envelope which will require investigation by skilful and resolute test pilots. The trials programme will first be conducted ashore and then on board the Vikramaditya. The shore segment will have two parts : launch over a 14 degree ski-jump, and recovery into a set of arrester wires using the tail-hook. The carrier trials will, essentially, be a repeat, except for two additional and crucial variables : deck-motion and relative wind.

The SBTF
The shore-based test facility (SBTF) being created at the Naval Air Station Goa, at considerable expense and effort, is yet one more manifestation of the serious IN-DRDO cooperation and commitment to the LCA-Navy. The Russians, who pioneered the STOBAR concept, successfully undertook the daunting task of converting the shore-based, Su-27K (or Su-33), MiG-29K and Su-25G, into carrier-borne versions. For testing these aircraft, and subsequently for training squadron pilots, they had created an elaborate facility at the Nitka Centre close to the Ukrainian port of Sevastopol.

The Indian SBTF, a replica of ‘Nitka’, will be equipped with a 14 degree ski-jump located at the end of a taxi-track, on a 150 foot high cliff overlooking the sea. A hydraulic arrester gear, with three wires, will be installed on a small stretch of parallel runway created for this purpose. The Luna optical landing aid, installed on Vikramaditya, will also be replicated here. The entire facility will be overseen by a flight-test and telemetry centre.

Trials Programme
Although sufficient data is available, from many sources on arrested recovery performance, in the case of LCA-Navy, the design of the tail-hook, its strength and positioning are critical factors which will need to be empirically tested. Starting with taxi engagements at increasing speeds, the trials will progress to actual arrested landings, and culminate at maximum landing weight. It is noteworthy that the F-35C version of the JSF has recently failed the taxi engagement test, because the tail-hook is, apparently, positioned too close to the undercarriage. After the wheels roll over the arrester gear, this particular geometry does not allow sufficient time for the disturbed wires to settle down as the hook tries to engage them.

The real unexplored territory for the trials team will be the ski-jump launch, which requires investigation of aircraft performance and behaviour in many areas. Some of these are: relationship of all-up weight to deck run, engine thrust and relative wind, undercarriage oleo compression on the ramp and sudden extension on exit, controllability at ski-jump exit and acceleration thereafter. A crucial factor in this phase will be accurate estimation of engine thrust available under given ambient conditions of temperature and pressure. The test team is hopeful that it will be possible to indicate the maximum thrust available from the aircraft power-plant as a number on the cockpit head-up display.

On successful completion of the SBTF phase, carrier compatibility trials will represent two significant challenges for the test team. Firstly, ground manoeuvering (with and without engine power) in the cramped confines of the hangar and flight-deck, while the ship is underway, will call for skill, forethought and planning if mishaps are to be avoided. Secondly, the aspect of ship-motion during launch and recovery will need to be approached with due care and prudence.

In addition to circular motion about three axes (roll, pitch and yaw), ships also tend to, unexpectedly, heave up and down in the vertical plane. Consequently the deck is either not where it was expected to be, or suddenly comes up and slams the aircraft. Often piloting skills are not enough to avoid hard impacts or over-stressing of components during shipboard operations in rough seas. Accurate recording of parameters and sensible stipulation of operating limits is called for otherwise as Cmde Maolankar puts it, “You will have either an over-designed aircraft or a broken (under-designed) one.”..."

Source: http://www.vayuaerospace.in/images1/The_LCA-NAVY.pdf (7.8Mb)

Genesis of the F-35 Joint Strike Fighter
Nov–Dec 2009 Paul M. Bevilaqua JOURNAL OF AIRCRAFT 2009; WRIGHT BROTHERS LECTURE Vol. 46, No. 6

“...The primary requirement for the Naval variant was the ability to take off and land on a carrier in 300 ft or less with a 20 kt wind over the deck. Lockheed Martin considered three alternative approaches. The first alternative was for the Navy to operate the same STOVL aircraft being developed for the Marines; this was certainly the easiest solution, but this aircraft would have less range/payload performance than a conventional Naval aircraft.

The second alternative was to remove the lift fan and adapt the roll control jets to blow the wing flaps. This would increase the wing lift, reducing the aircraft takeoff and landing speeds and enabling it to use the carrier catapult and arresting gear. However, the blown flaps on the F-4 Phantom had proved difficult to maintain and Lockheed Martin did not feel the Navy would favor this approach. Instead, it was decided to increase the wing area by enlarging the flaps and slats and adding a wingtip extension. The increased lift of the larger wing also reduced the takeoff and landing speeds and enabled use of the catapult and arresting gear. An additional benefit of the larger wing is that it gives the Naval variant greater range than either the Marine or Air Force variants, both by reducing the induced drag and by providing additional volume for fuel.

Because the carrier arresting system imposes greater loads on the landing gear and airframe than a conventional landing, the landing gear of the Naval variant was redesigned for a 25 fps vertical velocity, rather than 10 fps used for the conventional and STOVL variants. Similarly, the nose gear was redesigned for catapult launches. The additional airframe loads were handled through the use of cousin parts, which are stronger parts that replace conventional parts without changing the basic structural arrangement. For example, on the Air Force and Marine variants, the bulkhead that takes the main landing gear load is made of aluminum and is approximately 1/2 in: thick. The same bulkhead on the Naval variant is made of titanium and is about 3/4 in: thick. This technique was adapted from the F-16 production line, in which cousin parts were used to create variants of the same basic airframe for different customers who preferred different subsystems....

...The Skunk Works proposal was to build two aircraft. One would be devoted to STOVL testing, because this had always been perceived as the greatest challenge. The other would be first flown as the Air Force variant and then be modified by replacing the wing flaps and slats to become the Naval variant. Both aircraft would be built with the Naval structure. To reduce the cost of the demonstration, available components were used for subsystems that were not critical to the test objectives. For example, these aircraft used the nose gear from the F-15 and modified main landing gear from the A-6. The increased weight of these off-the-shelf components was offset by not including mission avionics and weapons bays on the demonstrator aircraft....” [This did not happen because the X-35A was converted to X-35B subsequently.]

Source: http://pdf.aiaa.org/getfile.cfm?urlX=-% ... 0%20%20%0A (PDF 7.7Mb) [very slow download]
OR
http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf (7.7Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 15 Feb 2015, 14:16
by f35phixer
starting soon real soon !!!!

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 15 Feb 2015, 16:53
by bring_it_on
f35phixer wrote:starting soon real soon !!!!



Are you referring to the UK F-35B's doing ski jump trials?

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 01:44
by spazsinbad
In case anyone is wondering about the OLS at INS Hansa seen above then the great website 'Live Fist' has more details today. I have e-mailed webmaster to see if more can be known about it. Go here: Shore-based Test Facility = SBTF

QUALITY PDF for some great graphics: https://www.scribd.com/document_downloa ... ension=pdf (27Mb)

CLDT = Centre Line Drop Tank
Third In The World: India's Shore-based STOBAR Facility
15 Feb 2015 Shiv Aroor

"Designed by Russia's Nevskoye Design Bureau (NDB) for India's Aeronautical Development Agency (ADA), the SBTF is an impressive facility that launches aircraft straight out over the Arabian Sea. The facility is also crucial to how the LCA Navy shapes up as a fighter platform for aircraft carriers. The facility is split into three zones: the take-off area, which comprises the ski-jump, restraining gear (Project 11430/Vikramaditya standard by OAO RAC MiG) and light signalling system, the landing area, which has a two 90 metre wire Proletarsky Zavod Svetlana arresting gear system capable of trapping aircraft up to 20 tons, providing a maximum deceleration during trapping of less than 4.5g.

The SBTF's 57 x 16 metre ski-jump is parabolic and assembled at a 14-degree angle, constructed using steel, concrete and a 10mm steel plate on top. The ski-jump tops off at 5.71 metres at the launch point....

...The crucial optical landing system (OLS), the LUNA-3E supplied by FSUE Elektropribor, is perhaps the most crucial part of the SBTF, providing non-stop visual cues to pilots on approach, to correct glide and approach paths before touchdown. The lights are visible to pilots out to 5-km at night and 3-km in daytime...."

Source: http://www.livefistdefence.com/2015/02/ ... ed_15.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 04:04
by f35phixer
bring_it_on wrote:
f35phixer wrote:starting soon real soon !!!!



Are you referring to the UK F-35B's doing ski jump trials?


a STOVL jet doing testing.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 04:34
by spazsinbad
MAGIC - thanks 'f35phixer' - great news. Apparently at AeroIndia soon info about the OLS will be available.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 05:49
by KamenRiderBlade
Am I the only one who feels India's new natively produced fighter looks ALOT like the "Mirage 2000"?

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 17:18
by spazsinbad
About the OLS at Goa:
Optical Landing System (OLS)
Is intended to generate continuous visual information to Pilot by means of Indicating Light Unit (ILU) consisting of five main and four mixed monochromatic lighting data sector with respect to prescribed glide slope during the final aircraft carrier approach.

Detection range of datum lights is about 5 km in the night-time and about 3 km in the day-time. Adjustment for indication lights assembly inclinations within range of + 1° to +9° for setting angle of the glide path is available.

Glide Slope angle for compensation of "eye-hook" distance changes for different aircraft types is provided within the range of-5° to +5°.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 18:29
by spazsinbad
Ski Jump at INS Hansa (NAS Goa) is on the West Coast of India whilst the jump direction is from East to West to be more or less over the sea just after exiting the ramp. I'll look to see if Google Earth has an up to date photo: now JUNE 2014. CLICK de PICs for the ZOOM view.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 16 Feb 2015, 19:13
by spazsinbad
Similar to the USN LSO setup (LSODS) Landing Signal Officer Display System (which has many components including a display which looks like this set up at INS Hansa SBTF at the OLS/Arrest Gear Test site).
TV Landing System SBTF
“To assist Landing Signal Officer (LSO) regarding position of aircraft approaching to land on Deck. TV Landing System provides aircraft visible distance of 6 Km, monitoring aircraft from 5 Km, auto tracking from 4.5 Km and measuring range and deviation from Glide path from 3 Km away from touchdown point. TV Landing System has two cameras mounted on landing runway axis and two cameras are installed on both sides from landing runway axis at distance of 16 m from axis for determination of distance to touch down.”

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 22 Feb 2015, 10:35
by spazsinbad
Did not notice this factoid about the SBTF Ski Jump Location earlier. Nice to have a long drop for testing.... Graphic from same source (click on it to ZOOM in).
"...“The Indian SBTF, a replica of ‘Nitka’, will be equipped with a 14 degree ski-jump located at the end of a taxi-track, on a 150 foot high cliff overlooking the sea.” http://www.vayuaerospace.in/images1/The_LCA-NAVY.pdf (7.8Mb)"

Airport type, Naval Air Station; Operator, Indian Navy; Location, Dabolim, Goa, India
INS Hansa; Elevation AMSL: 184 ft / 56 m http://en.wikipedia.org/wiki/INS_Hansa

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 01:31
by zerion
F-35 starting ski-jump testing this week.

http://www.reuters.com/article/2015/02/ ... AK20150224

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 02:05
by spazsinbad
Thanks 'zerion'. Probably SHALAL has misunderstood something here (from 'zerion' URL above):
Lockheed F-35 heads for the ski jump in next key round of tests
24 Feb 2015 Andrea Shalal (Editing by Matthew Lewis) [I BLAME MAFEW :mrgreen: ]

"...Two UK pilots will test the ability of the new warplane to take off from upward-sloping ski-jump ramps used on aircraft carriers like those operated by Britain and Italy. The ramps launch the jets forward and upward, reducing the thrust needed. [same same frust STOVL MODE IV but reduces the required takeoff distance - a KPP requirement indeedy]

[AND in the SPACE of a day the price has been reduced from 1.5 Trill Doritos to 0.5 (in Oz) to now...] ..."After 14 years of development, early cost overruns and schedule delays, the $400 billion F-35 fighter jet program is becoming an operational reality for the U.S. military. Over 120 jets are flying at nine U.S. bases...." [I LIKE IT! :devil: ]

Source: http://www.reuters.com/article/2015/02/ ... AK20150224

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 02:54
by KamenRiderBlade
One day, somebody might attempt to combine the Catapult + Ski Jump and we will see the wonders of both technologies combined.

=D

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 03:01
by spazsinbad
That idea has been canvassed before and does not make sense. The STOVL aircraft does the trick nicely UNLESS you are referring to a NAVALISED Aircraft such as LCA-NAVY or perhaps F-35C which may ski jump via catapult in A/B and arrest etc.? Still does not make sense because steam/EMALS can hurl heavy aircraft over a short distance similar to that taken up by the ski jump fitted. You need to be more clear about what is envisaged.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 03:26
by KamenRiderBlade
spazsinbad wrote:That idea has been canvassed before and does not make sense. The STOVL aircraft does the trick nicely UNLESS you are referring to a NAVALISED Aircraft such as LCA-NAVY or perhaps F-35C which may ski jump via catapult in A/B and arrest etc.? Still does not make sense because steam/EMALS can hurl heavy aircraft over a short distance similar to that taken up by the ski jump fitted. You need to be more clear about what is envisaged.


A EMALS based catapult that launches the aircraft across the launching deck, at the end of the deck is a Ski-Jump.

Catapult + Ski-jump

=D

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 03:52
by spazsinbad
An EMALS can fling anything envisaged for the near term I'm told - I see no advantage for ski jump at all. One could argue that a small scale EMALS may do the work required in the shortest distance for a given known aircraft/weight. However IF the future needs are envisaged then perhaps a longer/larger EMALS is more sensible given that aircraft carriers have lives longer than aircraft carried - usually (that equation may change however).

Anyway the problem as told and now retold is the slow speed flying capabilities of any ski jumpin' aircraft. STOVL MODE IV fits that bill nicely. Carrier Enabled aircraft less so - usually that means they have a limited takeoff weight. NOW throw a heavily laden carrier based aircraft at a ski jump so as to achieve min safe flying control speed at the top of the jump. I have an almighty undercarriage collapse going up the jump in my mind's eye - but you may not.

However if you envisage an EMALS catapult embedded IN the ski jump then (with a lesser angle) perhaps this is more sensible? AFAIK [French Navy trial] adding a small upward part at the end of a conventional catapult has been tried (and not deemed useful) because perhaps that upward part was not very long as I recall. So back to you....

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 04:04
by KamenRiderBlade
spazsinbad wrote:An EMALS can fling anything envisaged for the near term I'm told - I see no advantage for ski jump at all. One could argue that a small scale EMALS may do the work required in the shortest distance for a given known aircraft/weight. However IF the future needs are envisaged then perhaps a longer/larger EMALS is more sensible given that aircraft carriers have lives longer than aircraft carried - usually (that equation may change however).

Anyway the problem as told and now retold is the slow speed flying capabilities of any ski jumpin' aircraft. STOVL MODE IV fits that bill nicely. Carrier Enabled aircraft less so - usually that means they have a limited takeoff weight. NOW throw a heavily laden carrier based aircraft at a ski jump so as to achieve min safe flying control speed at the top of the jump. I have an almighty undercarriage collapse going up the jump in my mind's eye - but you may not.

However if you envisage an EMALS catapult embedded IN the ski jump then (with a lesser angle) perhaps this is more sensible? AFAIK [French Navy trial] adding a small upward part at the end of a conventional catapult has been tried (and not deemed useful) because perhaps that upward part was not very long as I recall. So back to you....


http://www.dtic.mil/dtic/tr/fulltext/u2/a237265.pdf

The reason I mention the "Ski Jump + Catapult" is that it was either you Spaz, or somebody else who linked an USAF study on a mobile land based Ski Ramp that can be stored somewhere and moved to anywhere on a runway as needed to shorten takeoff distances for most aircraft. In the event that the runways get cratered, you can move a Ski Ramp to a good section of a runway and allow aircraft to takeoff in a short distance.

My logic being that if it can help shorten the distance of combat aircraft taking off, it could help at least increase the payload that the aircraft can take off with from a carrier assuming the existing carrier doesn't change dimensions.

If there is too much engineering that needs to be done to make this work on top of the existing catapult, than save it as an idea down the line for any future carrier designs.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 04:33
by madrat
KamenRiderBlade wrote:One day, somebody might attempt to combine the Catapult + Ski Jump and we will see the wonders of both technologies combined.

=D


Or using multiple decks so you can launch first down a slope then back up off the ramp. I like the idea of an external rail away from the deck that does the same thing, with the rail vertically reminiscent of an S-curve. Keep launch space excluded from recovery and unloading space.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 05:02
by spazsinbad
As I recall 'madrat' introduced some ideas about catdepultingwhilstskijumping onandoff multiple decks with a hair dryer at the other end (or both) to provide extra vertical lift over the ramp? I'll find that or those threads at some point if required.

Meanwhile back to KRB thoughts about land based aircraft using a portable ski jump from uncratered portions of conventional runways.... Without looking at the PDF again I would suggest that the ski jump angle is less than 12-14 degrees as seen on flat deck ski jumps today (UK & Ruskie/Indian respectively). Then there is another PDF about 'gravity assisted land based ski jumping which 'madrat' may refer to obliquely (when at first the aircraft goes down the dip then up [a large crater hollowed out]?

KRB:
"...My logic being that if it can help shorten the distance of combat aircraft taking off, it could help at least increase the payload that the aircraft can take off with from a carrier assuming the existing carrier doesn't change dimensions.

If there is too much engineering that needs to be done to make this work on top of the existing catapult, than save it as an idea down the line for any future carrier designs."

Again it would be nice if you were more specific. For some 60 or more years naval aircraft have been assisted off their respective flat decks by hydraulic (even earlier with some other weird gizmology) and now STEAM with Future EMALS catapults. The logic and utility of these catapults is well known and quantified and still around for conventional carriers because it is useful. The penalties of such usefulness are also well known when first the naval aircraft is catapulted and then recovered via arrestor gear.

If one reads the info about Tejas LCA-NAVY one has the gist that the undercarriage was initially over engineered, after following Russian design suggestions? Now another undercarriage has been designed that enables the same events (ski jumping and arrest) with much less weight - always a good thing. Whilst there is a comment in one of the PDFs that says to the effect 'things need to be engineered precisely so that there is no over/under engineering' for the LCA-NAVY, precisely so that max weight for take off is enabled via ski jump in distance allowed.

Once again I'm a little stuck about what is envisaged. An EMALS catapult will fling anything allowable up to the breaking point of said flungee. For an A-4 Skyhawk that max. horizontal G allowable was 9! OUCH! For naval aircraft today that is now probably about 7 G but I'm only guessing. VX-23 Test Pilots have mentioned going up to 6G during their Hornet catapult tests which is above what is required usually on USN catapults. So there are a few factors involved in engineering a catapult / arrest aircraft - let alone design a functioning arrestor hook (without wirebrushing the team). :mrgreen:

P'raps an EMALS incorporated into a gentle ski jump may be OK but why? EMALS is able to at first gently accelerate the aircraft (whereas STEAM has the max G right at beginning) to intelligently increase acceleration to the required endspeed. IF a nugget T-45C pilot keeps his feet on the brakes during catapulting the EMALS will recognise a problem and increase acceleration to required endspeed - despite the smoking brakes and blown tyres. Yay EMALS!

So my suggestion is: go with EMALS on aircraft carriers and go with Ski Jumps on STOVL carriers. Even Indian NEXT carrier after the one being built now is said to be going to have EMALS (via recent tech agreements with US after PrezVisit) and EVEN the Ruskinators are saying similar - although their next carrier construction is TO BE FINISHED by 2025 hence - WOT! :devil:

India now puts aircraft carrier plan on fast track
23 Feb 2015 Rajat Pandit, TNN

"...But the carrier will definitely have CATOBAR (catapult assisted take-off but arrested recovery) configuration for launching fighters as well as heavier aircraft from its deck. Towards this end, India has already asked the US to share technology for EMALS (electromagnetic aircraft launch systems), developed by General Atomics, under the bilateral Defence Trade and Technology Initiative, as reported by TOI earlier...."

Source: http://timesofindia.indiatimes.com/indi ... 336472.cms

Russia May Finalize its Flagship Aircraft Carrier by 2025
15 Feb 2015 Russia

"The construction of a flagship air carrier for the Russian Navy may be finalized before 2025, a Russian Navy spokesman said....

...He added that the aircraft-related research work is now under way and that several projects related to the vessel's construction are already on the table.

Earlier, the Russian Navy's Deputy Commander on Armament Victor Bursuk said that the new aircraft carrier would be built after 2030...."

Source: http://sputniknews.com/russia/20150215/1018305548.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 05:10
by KamenRiderBlade
Realistically, I wouldn't suggest making the change now in production ships.

Just investigate the concept for future designs.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 05:30
by spazsinbad
Realistically I do not see the benefit of what exactly? Please elaborate. Is the EMALS incorporated in the ski jump or as you have first suggested? Where is the benefit from the options already canvassed. I see the STOBAR players going conventional and even perhaps NUCKCLEAR for the benefits - including electric power generation for EMALS!

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 05:36
by KamenRiderBlade
spazsinbad wrote:Realistically I do not see the benefit of what exactly? Please elaborate. Is the EMALS incorporated in the ski jump or as you have first suggested? Where is the benefit from the options already canvassed. I see the STOBAR players going conventional and even perhaps NUCKCLEAR for the benefits - including electric power generation for EMALS!


The EMALS could be incorporated into the ramp or stopped just before the start point of the ramp.

The design depends on the test data really.

But the benefits would be allowing even heavier loads than existing max gross weights to take off.

But if there is no aircraft that needs to go heavier, than the existing solutions would work.

I'm making assumptions that future aircraft will be pretty heavy or have options to load up in weapons + fuel to be even heavier than current limits.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 05:48
by spazsinbad
KRB says:
"...But the benefits would be allowing even heavier loads than existing max gross weights to take off....

...I'm making assumptions that future aircraft will be pretty heavy or have options to load up in weapons + fuel to be even heavier than current limits."

Max Gross Weight is for the aircraft - not the catapults in use today or in future. I have read that EMALS is scalable but at moment engineered for what is envisaged at both the HIGH and the LOW weight ends (to include small UAVs for example).

Current USN steam catapults are very effective as shown on probably the very long thread near the beginning when peeps were questioning my knowledge/cred about such matters as conventional catapulting. So the LIMIT is not for current catapults but for aircraft. May I repeat: Aircraft are designed for flat decks or ski jumps as they are OR may be built in some reasonable future time (if there is no requirement to operate off existing decks). It will be probably be a cold day in hell if a SHIP/Carrier is ever designed for an aircraft. :mrgreen: :devil: :mrgreen: Why? Because once that is done future aircraft will have to conform to the limits of the ship. No? Or are we going to have new ships endlessly redesigned for new aircraft? Don't think so - but - hey - in your dreams. :doh: :drool:

Aircraft are the factors that break the existing gear. Aircraft WILL NOT break existing or future gear on a carrier (unless minor mods required as we have seen for LHAs & CVNs - bearing in mind ships go for regular refits when minor mods are carried out all the time because these ships have a long life these days and are designed for same - probably aircraft also) as we know for the F-35B/Cs - which is also the case for new aircraft [knowing that the limits of ship equipment not breached in design phase of naval aircraft].

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 06:54
by spazsinbad
An example of a 'skijump' before time began c.Early1940s....
Commander Nat Gould RAN
14 Dec 2010 by Geoff Raebel

“...the convoy was HMS Argus, the 1918 progenitor of all aircraft carriers. With Hurricanes as deck cargo, they approached to within a couple of hundred miles of Murmansk when she flew off the Hurricanes to find their own way to Russia. Two damaged their under carriages on the launching hump at the end of the deck and had to fly wheels down all the way....” c. mid 1941"

Photos show BARRACUDAS mit HUMP 1944: http://images.yuku.com.s3.amazonaws.com ... b3e438.jpg
&
http://images.yuku.com.s3.amazonaws.com ... 224cc3.jpg

Source: http://www.raafinrussia.com/commandernatgouldran.html

And perhaps least remembered is the initial lower angled ski jump as used by RN. I'll guess increasing the angle was more beneficial performance-wize for the STOVL aircraft going ballistic under flying speed but still controllable with the thingamejigs whilst it accelerated Upwards:
"...ski jump slope was initially 7°, later increased to 12° for all..."

Source: http://www.flightglobal.com/pdfarchive/ ... 00091.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 07:01
by KamenRiderBlade
spazsinbad wrote:KRB says:
"...But the benefits would be allowing even heavier loads than existing max gross weights to take off....

...I'm making assumptions that future aircraft will be pretty heavy or have options to load up in weapons + fuel to be even heavier than current limits."

Max Gross Weight is for the aircraft - not the catapults in use today or in future. I have read that EMALS is scalable but at moment engineered for what is envisaged at both the HIGH and the LOW weight ends (to include small UAVs for example).

Current USN steam catapults are very effective as shown on probably the very long thread near the beginning when peeps were questioning my knowledge/cred about such matters as conventional catapulting. So the LIMIT is not for current catapults but for aircraft. May I repeat: Aircraft are designed for flat decks or ski jumps as they are OR may be built in some reasonable future time (if there is no requirement to operate off existing decks). It will be probably be a cold day in hell if a SHIP/Carrier is ever designed for an aircraft. :mrgreen: :devil: :mrgreen: Why? Because once that is done future aircraft will have to conform to the limits of the ship. No? Or are we going to have new ships endlessly redesigned for new aircraft? Don't think so - but - hey - in your dreams. :doh: :drool:

Aircraft are the factors that break the existing gear. Aircraft WILL NOT break existing or future gear on a carrier (unless minor mods required as we have seen for LHAs & CVNs - bearing in mind ships go for regular refits when minor mods are carried out all the time because these ships have a long life these days and are designed for same - probably aircraft also) as we know for the F-35B/Cs - which is also the case for new aircraft [knowing that the limits of ship equipment not breached in design phase of naval aircraft].


Fair enough, I wasn't really expecting them to go with the Ski-Ramp catapult anytime in the near future.

It's one of those wild ideas.

The fact that the USAF tested a Ski-Ramp for land usage was pretty cool.

Hopefully they'll make use of that technology in the near future.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 07:05
by spazsinbad
I would have thought the USMC would get such a notion (portable ski jump). I have read that decades ago it was considered but I'll guess now that the F-35B is so versatile in take off and landing in MODE FOUR that a ski jump is irrelevant ashore and even afloat.

AS for damaged runways with portable ski jumps? It seems the bomb damage repair brigade have it covered. OR NOT - if they have survived.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 07:26
by KamenRiderBlade
spazsinbad wrote:I would have thought the USMC would get such a notion (portable ski jump). I have read that decades ago it was considered but I'll guess now that the F-35B is so versatile in take off and landing in MODE FOUR that a ski jump is irrelevant ashore and even afloat.

AS for damaged runways with portable ski jumps? It seems the bomb damage repair brigade have it covered. OR NOT - if they have survived.


How many bomb damage repair brigades are assigned to each airbase?

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 25 Feb 2015, 07:47
by spazsinbad
Probably anyone who can man a shovel gets to be in it? Quick Drying Concrete is probably very quick these days. Whatever. I'll upload a new 'ski jump' PDF in a day or so. There is one on the SpazSinbad pages already but it does not include the recent GOA SBTF info. I was going to wait for any RECENT (as noted above) F-35B material - so perhaps I will wait as the SBTF material is on this thread anyway - the rest of info is in PDF more or less. So go here:

Folder: SkiJumpInfo28may2014

SkiJumpInfoCVF&othersTesting28may2014pp163.pdf (18Mb)

https://onedrive.live.com/?cid=cbcd63d6 ... =822839791

I'll put the same PDF here in a few minutes:

Folder: F-35 Lightning II Material

https://drive.google.com/?authuser=0#fo ... EJvU09qWDQ

DO NOT FORGET - DO NOT LEFT Mouse click on a file - RIGHT MOUSE CLICK & 'SAVE AS' to your computer to view with the latest Adobe Reader suitable for your Operating System. Go here: http://get.adobe.com/reader/otherversions/

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 06 Mar 2015, 04:12
by spazsinbad
Repair Hombres and Hombresses at work...
Marines join Kadena Airmen for contingency exercise
05 Mar 2015 Airman 1st Class John Linzmeier, 18th Wing Public Affairs

"KADENA AIR BASE, Japan (AFNS) -- Civil engineer Airmen and combat engineer Marines participated in a joint airfield damage and repair contingency exercise Feb. 26, at Kadena Air Base, Japan.

Joint forces from the 172nd and 171st Engineering Companies and 18th Civil Engineer Squadron worked together to repair a damaged runway in response to a simulated air attack.

"Our mission is to reestablish an operational runway so that we can get planes in and out," said 2nd Lt. David Brown-Dawson, the 18th CES Airfield Damage and Repair officer in charge. "If an attack were to actually happen, we need to utilize all of our assets, and that's military wide. Not just Air Force, not just Navy, Army and the Marines; we all need come together because we're all fighting the same fight."

The exercise gave members from both services the opportunity to showcase their runway repair capabilities and helped them establish more effective ways to communicate and react in a crisis situation.

"It's been really helpful to come out and see how the Air Force does it because this is their bread and butter," said Marine Corps 1st Lt. John Mutton, the 172nd Marine Wing Support Squadron combat engineer officer, "They are also able to see how we operate as well, which allows us to establish relations that are really helpful for the future."...

...While each service follows different response procedures, the exercise helped them to understand how one another operate and combine assets improving their ability to work together."

PHOTO: http://media.dma.mil/2015/Mar/05/200101 ... 56-178.JPG
Caption: "Loaders, operated by 18th Civil Engineer Group Airmen, level out a 50-foot crater on a mock runway Feb. 26, 2015, at Kadena Air Base, Japan. Marines from the 172nd and 171st Engineering Companies participated in a joint airfield damage and repair contingency exercise to learn how civil engineer Airmen respond to airfield damage and to strengthen joint capabilities of reestablishing an operational runway. (U.S. Air Force photo/Airman 1st Class John Linzmeier)"

Source: http://www.af.mil/News/ArticleDisplay/t ... rcise.aspx

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 06 Mar 2015, 18:41
by spazsinbad
Thanks to 'bager1968' on the NavWeaps forum here [ http://warships1discussionboards.yuku.c ... sert-Storm ] is the 1991 FOCHed 1.5 degree catapult RAMP test photie:

http://s22.photobucket.com/user/Bager19 ... u.jpg.html
&
http://s22.photobucket.com/user/Bager19 ... x.gif.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 12 Mar 2015, 09:54
by spazsinbad
LCA Navy Maiden Ski Jump Details & Analysis
21 Dec 2014 UNK

"LCA Navy's maiden ski jump take-off at SBTF at INS Hansa on December 20, 2014 was a milestone event, not because it happened (Ski jump take-off are as old as the Harriers!), but because it happened in hands-off automated take-off mode!

Yes, LCA Navy feature hands-off take-off using ski-jump to ensure smooth transition to stable flight, and hands-off landing with steady AOA, autothrottle approach, flareless touchdown, and arrester hook engagement. During take-off and landing the pilot is required to only give steering inputs to stay on the center line.

According to a DRDO press release on the test flight, Naval Prototype 1 (NP-1) - piloted by Commodore Jaideep Maolankar, the Chief Test Pilot of National Flight Test Center - had a perfect flight with results matching the predicted ones to the letter. The flight validated the hands-off take-off algorithm of the Flight Control Software (FCS).

NP-1 attempted the ski-jump after a 300-m roll in clean configuration presumably with full internal fuel.

A safe take-off required 150 knot at a climb rate of 6.4 degrees. But, the aircraft achieved higher acceleration with a climb rate of around 11 degrees.

In the tests ahead, NP1 will progressively reduce the length of its take-off roll and increase payload. INS Vikramaditya, which could one day base LCA Navy, has a total deck length of 273-m. The maximum take off length available is between 160-180 metres.

The ultimate goal for the LCA Navy program is to demonstrate a full load take-off with 90-m roll.

Five more ski-jump take-offs are planned in the current series of tests.

"Based on the test points achieved, we will schedule the next leg of trials," DRDO Director-General (Aero) Dr K Tamilmani told OneIndia.com.

According to Tamilmani, NP-1 will start arrester hook landing trials within 6-8 months.

It's pertinent to remember that LCA Navy is in Phase-1 of its development, which involves using a LCA Mk-1 modified to take off using a ski jump and perform arrested landing. Phase 1 is a technology development and demonstration phase.

In Phase 2, LCA Navy will be certified for carrier operations using aircraft built in the Tejas Mk2 configuration, powered by GE-414-INS6 engine with a max thrust of 22,000 lbs.

Only Phase 2 aircraft will participate in carrier operation certification
, with Phase 1 aircraft being reserved exclusively for SBTF operations.”

PHOTO: http://i.imgur.com/rWmEClY.jpg

Source: http://defesa.forums-free.com/tejas-ind ... 64s60.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 12 Mar 2015, 22:21
by bring_it_on
Does anyone have transcripts or a video of this ?

http://aerosociety.com/Events/Event-Lis ... on-Fighter

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 14 Mar 2015, 01:28
by spazsinbad
A Demo of the tech at SBTF on show in Russian Northern Waters:
Arctic drills: Russia’s Northern fleet pilots polish deck takeoff & landing skills
Published on Oct 1, 2014 RT

"Naval pilots of Russia’s Northern Fleet successfully executed training exercises flying the SU-25 and SU-33 jets off the Admiral Kuznetsov aircraft-cruiser."


Re: F-35B/C and the Ski-Jump?

Unread postPosted: 11 May 2016, 20:21
by spazsinbad
Naval Tejas successfully tested in Goa, will fly off aircraft carrier next year
10 May 2016 Ajai Shukla

"The naval version of the Tejas Light Combat Aircraft (LCA), which will operate from India’s indigenous aircraft carrier, INS Vikrant, after it is commissioned in 2018, has completed a successful flight-test campaign in Goa.

Commodore (Retired) CD Balaji, chief of the Aeronautical Development Agency (ADA), which oversees the Tejas development programme, told Business Standard that taking off and landing from a 200-metre deck has been fully established. So has “hot-refuelling” --- topping up the aircraft after a sortie with the engine running and the pilot in the cockpit --- which allows a rapid turnaround between sorties.

For the navy, it is vital to ready the Tejas for the INS Vikrant and, subsequently, INS Vishal. The MiG-29K will be the medium fighter on INS Vikrant, as it already is on INS Vikramaditya. The Tejas is crucial for filling in the light fighter slot.

Balaji reveals a committed navy is funding 40 per cent of the development cost of the Naval Tejas. The MoD has allocated Rs 3,650 crore for the naval programme.

The ADA chief described the flight trials in Goa between March 27 and April 25, in which two Naval Tejas prototypes flew 33 sorties from a Shore Based Test Facility (SBTF) -- a full-scale replica of an aircraft carrier deck. Built on land, the SBTF allows carrier deck take-offs and landings to be validated, without unduly endangering an aircraft carrier, or an aircraft prototype and pilot....

...In December 2014, the Naval Tejas had taken off from the SBTF ski-jump after rolling 300 metres. Now, the fighter has proven it can take off from just 200 metres, even carrying two R-73 close combat missiles.

“With this campaign, ski-jump launches are no longer a challenge. We will now explore the limits the fighter can be taken to. We will further fine-tune the control law software to take-off with higher payloads,” said Balaji.

In aircraft carrier combat operations at sea, the Naval Tejas must take off with up to 3.5 tonnes of payload--- more fuel for longer range; and more weapons for a lethal punch. For this, the aircraft carrier would steam into the wind, ensuring a “wind-over-deck speed” of up to 20 knots. That would provide added lift to the aircraft, allowing higher payloads....

...Similarly, fitting the Tejas Mark-2 with the more powerful General Electric F-414 engine (the current Mark -1 fighter has the smaller F-404 engine) will allow greater payloads and more ambitious mission objectives.

Even more challenging than taking off from a 200-metre carrier deck is to land an aircraft back on the carrier. This requires touching down precisely at the edge of the runway, aligning the approach with the help of an “optical landing system” and a “landing control post”. At landing, an “arresting gear system” --- including wire cables across the deck runway --- latches onto a hook on the fighter’s tail and rapidly decelerates it to a halt.

“In the current campaign, the Tejas did over 60 approaches (without actually touching down) to gather data for fine-tuning the control law software. In the next campaign this month, we will do “touch and go” approaches to validate the software and then graduate to full landings,” explains Balaji.

Finally, the Naval Tejas demonstrated its “fuel jettison” capability --- a safety feature that allows the fighter to quickly jettison on-board fuel if it encounters a problem soon after launch and must quickly return for an emergency landing on the carrier.

“By mid-2017, we will have established on the SBTF that the Naval Tejas can be flown off an actual carrier, and we will then graduate to ship-based testing. We currently have two prototypes in testing, and will build a third by then”, says a satisfied ADA chief."

PHOTO: http://bsmedia.business-standard.com/_m ... 20-043.jpg

Source: http://www.business-standard.com/articl ... 050_1.html

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 18 May 2016, 22:42
by spazsinbad
Indian Navy's indigenous fighter successfully completes flight tests
17 May 2016 Rahul Bedi

"India's Aeronautical Development Agency has made key progress in the development of the long-delayed naval version of the locally designed Light Combat Aircraft (Navy) or LCA(N), after two prototypes successfully undertook 33 sorties from the Indian Navy's (IN's) shore-based testing facility (SBTF) at INS Hansa in the southwestern state of Goa.

Between 27 March and 25 April two prototypes (NP1 & 2) carrying two Russian Vympel R-73 (AA-11 'Archer') air-to-air missiles each had validated 'ski-jump' trials from the SBTF, which replicates an aircraft carrier deck, according to IN sources.

They said both prototypes - designed by Hindustan Aeronautics Limited (HAL) with stronger landing gear than the standard LCA to absorb the additional forces - took flight after rolling 200 m at the facility...."

Source: http://www.janes.com/article/60396/indi ... ight-tests

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 18 May 2016, 23:13
by popcorn
Tejas should serve as the 'lo' in a 'hi-lo' mix for their CAW. It will be interesting to see which platform will constitute the 'hi' capability.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 19 May 2016, 13:27
by mixelflick
"Naval pilots of Russia’s Northern Fleet successfully executed training exercises flying the SU-25 and SU-33 jets off the Admiral Kuznetsov aircraft-cruiser."[/quote]
[/quote]

Thought I read where they opted for Mig-29K, vs SU-33's. I thought that odd, given the SU-33's much more robust range, payload etc.. Is it simply due to the fact the carrier can carry more Mig-29's vs. SU-33's?

Pricepoint? Or something else I'm missing??

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 21 May 2016, 21:34
by whitewhale
mixelflick wrote:Thought I read where they opted for Mig-29K, vs SU-33's. I thought that odd, given the SU-33's much more robust range, payload etc.. Is it simply due to the fact the carrier can carry more Mig-29's vs. SU-33's?

Pricepoint? Or something else I'm missing??


A touch (or more) off topic but there probably aren't enough available 33's, they only built around 30 of them and the rumour mill suggests that 'hanger queens' doesn't quite cover the reliability, or lack there of...

A bit more on topic but I was chatting with an aerodynamicist friend (automotive not military world though!) who is also following the build of the CVF and he suggested to me that the profile of the ramp could increase the WOD by several percent providing the flow isn't disrupted by air deflecting off the islands. Would be a nice free perk if it happens.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 30 May 2016, 17:00
by spazsinbad
On previous page there is a story about repairing runways viewtopic.php?f=22&t=14082&p=286706&hilit=Hombresses#p286706 so here is some more....
Filling the gap: Airmen, Marines and Sailors practice fixing damaged airfields
26 May 2016 Senior Airman Omari Bernard, 18th Wing Public Affairs

KADENA AIR BASE, Japan (AFNS) -- Civil engineer Airmen, combat engineer Marines and Navy Seabees trained together May 18-19 during a joint airfield damage and repair contingency exercise held at Kadena Air Base....

...Although there may be differences between the training of the services, their objectives are the same -- fill craters and get the airfield operational again.

"The steps are a little bit different, but in essence the steps are the same," said Marine Staff Sgt. Justin Luk, an MWSS 172 combat engineer. "Assess the crater, make it flat and from there we fill it in."...

..."It was a good learning opportunity for some of our guys to get some experience on something they haven't done before," said Petty Officer 3rd Class Darcel Tinner, an NMCB 4 Seabee.

From Tinner's experience, repairing damaged airfields for the Navy involves more manual work than the use of heavy machinery.

"We'll fill holes by hand compared to us using machines," Tinner said. "If there's anything we'll take away from this, it's to use more machines."..."

Source: http://www.af.mil/News/ArticleDisplay/t ... ields.aspx

Don’t Call it a Comeback
July 2015 Amy McCullough

"...Today, Silver Flag is part of the expanding PRTC at Andersen. Some 1,200 Air Force engineering and force support students are trained in 13 Air Force specialty codes on the campus each year on subjects from airfield damage repair to bare base electrical layout and reverse osmosis water purification.

Beginning in the second quarter of Fiscal 2016, USAF plans to reincorporate explosive ordnance disposal into Silver Flag training, said Mares. The training was part of the curriculum “until about 2000, but due to the high [operations] tempo for EOD airmen, they didn’t have the manpower to support all the deployments [to Afghanistan and Iraq] as well as the training,” Mares said in an April interview. Now that combat operations in Afghanistan have wound down and the US presence in the country is getting smaller, EOD can return to the curriculum.

The Air Force is in the “infancy” stages of instituting large-scale changes to the way it repairs runways after an attack. EOD will play a major role in this new methodology, said Mares.

Filling A Hole
“We are currently still teaching legacy airfield damage repair field methodology … based on Cold War technology and … threats … but there are some new and improved threats from adversaries in the region that have forced us to come up with a new methodology for recovering airfields,” he said. “We have always trained to the threat of fixing three 50-foot craters in four hours. Now, the new threat is going to be potentially 20 to 100 six-foot craters, so there are going to be many more pieces of damage, but of a smaller nature.”


There are more than 5,500 missiles pointed at US forces and allies in the region, said Maj. Justin Pendry, PAC­AF legislative liaison. In an effort to address the threat, Pacific Air Forces is positioning airfield damage repair kits at locations throughout its area of responsibility to enable remote bases to quickly get runways up and running in the event of an attack.

Because of its strategic location in the Pacific and its two runways, Andersen will get four of the kits. One for the 554th RED HORSE, two for the 36th Civil Engineering Squadron, and one for Silver Flag training, enabling instructors to introduce PACAF airmen to the new technology, said DeRosa.

The large kits are designed to provide everything crews need to fill a crater in the event of an attack, including heavy construction equipment such as rollers, dump trucks, and bulldozers, DeRosa said. “They are coming in piecemeal over the next several months,” he said of the equipment.

PACAF will standardize the kits across the region, though it is scaling the kit sizes based on need. As for Andersen, “the expectation is [that an adversary] would send more missiles our way to take out more of the runway and we’d have more runway to repair,” DeRosa said.

The actual method for filling the holes is changing. Instead of using compacted dirt and then topping it with a folded fiberglass mat, the Air Force is moving to a process called flowable fill—“more of a very thick slurry” used to fill the crater, said DeRosa. “It’s quicker because you pretty much just pump it into a hole, skim it off, and let it set.”

Flowable fill is a semi-permanent repair designed to sustain thousands of aircraft passes, said Maj. Robert Liu, expeditionary programs chief at the Air Force Civil Engineer Center (AFCEC) at Tyndall AFB, Fla.

There are three lines of runway repair: repair, mitigation, and assessment. The kits are intended for repair only, though AFCEC is researching ways to improve the other two lines.

The goal is to take the human factor out as much as possible. For example, the center has already started testing a three-kilowatt Zeuss III laser and robotic arm, to be mounted on mine-resistant, ambush-protected vehicles, said Liu.

Dubbed the Recovery of Air base Denied by Ordnance, or RADBO, system, the laser is meant to neutralize unexploded ordnance and improve UXO removal capability...."

Source: http://www.airforcemag.com/MagazineArch ... 202015/Don’t-Call-it--a-Comeback.aspx

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2016, 01:51
by popcorn
Interesting stuff Spaz...

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2016, 05:49
by KamenRiderBlade
Cluster bombs still have a perfectly good use =D

Runway Disabler

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2016, 06:04
by popcorn
From the linked article.

...The goal is to take the human factor out as much as possible. For example, the center has already started testing a three-kilowatt Zeuss III laser and robotic arm, to be mounted on mine-resistant, ambush-protected vehicles, said Liu.

Dubbed the Recovery of Air base Denied by Ordnance, or RADBO, system, the laser is meant to neutralize unexploded ordnance and improve UXO removal capability...."

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2016, 08:13
by 35_aoa
KamenRiderBlade wrote:Cluster bombs still have a perfectly good use =D

Runway Disabler


Until 2018, at least for the US military…...

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 31 May 2016, 17:53
by zerion
KamenRiderBlade wrote:Cluster bombs still have a perfectly good use =D

Runway Disabler

TLAM-D :D :D :D

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 22 Jun 2019, 17:44
by spazsinbad
On previous page this thread is the Indian Navy TEJAS saga beginning - it is ongoing with some worries about GOA testing.
Landing Tejas Jet On An Aircraft Carrier: Small Team Fights Big Deadline
11 Jun 2019 Vishnu Som

"In December, the Defence Ministry is likely to take a call on whether to shut down or continue investing in the project to develop an aircraft carrier-based variant of the indigenous Light Combat Aircraft Tejas.

...The government, which has already committed Rs. 3,500 crore to develop the fighter, needs a straight answer. Will the prototypes of the Tejas-N (Naval), now being tested, eventually result in a multi-role carrier-borne fighter good enough to hold its own against emerging threats in the Indian Ocean region? And can advanced variants of the prototypes, called the LCA-N Mk-2, be developed, manufactured and deployed within a finite period of five to seven years?

Left with no choice but to speed up their development programme, a small core team of pilots, engineers and design-team members from the Indian Navy, the Aeronautical Design Agency (ADA) and Hindustan Aeronautics Limited (HAL) is fighting against time to clear key development goals - the biggest one, at the moment, is to ensure that the 10.5-tonne fighter, flying at a speed of just under 260 kmph (140 knots), can approach a shore-based replica of the deck of an aircraft carrier, descend rapidly, land, snare an arresting wire on the runway with a hook mounted in its fuselage and come to a violent halt in just 130 metres. That's what it takes to make an 'arrested landing' on the deck of an aircraft carrier, a feat achieved by a handful of fighter jets developed in the US, Russia, the UK, France and, more recently, China.

Achieving this successfully, over and over again at the Shore Based Test Facility in Goa, will validate one of the most important design features on the LCA-N - its ability to handle the incredible stresses of making an 'arrested landing' on the deck of an aircraft carrier. It is only once the shore tests are successful that naval test pilots leading the development effort on the LCA-N prototypes can graduate to the next step - making an actual landing on India's only operational aircraft carrier, INS Vikramaditya.

Key members of the LCA-N development team whom NDTV has spoken to say they have flown 60 sorties in approximately the last one month at the Goa test facility and are ready to commence the key landing trials once monsoon is over. To eventually make an approach onto the deck of INS Vikramaditya, LCA-N engineers and pilots need to be confident that the fighter can slam down onto the deck of a carrier at a 'sink rate' (rate of descent) of approximately 7.5 metres per second (1,500 feet per minute) without being damaged. Though they may not test the fighter to this limit immediately, they need to successfully prove that they can land with a sink rate of 5.6 metres per second to be qualified for carrier trials. At the moment, the jet has been tested with a sink rate of 5.1 metres per second. Engineers and pilots in the project are certain that they are on track to meet their landing certification target.

Assuming, the LCA-N is qualified to make an approach onto the deck of the INS Vikramaditya, there are still two key hurdles that need to be overcome. Test pilots operating the fighter will need to experience, first hand, the impact of displaced air over the deck of the aircraft carrier moments before it touches down. For a safe arrested landing, the LCA-N will need to hold a near-constant air speed of between 240-260 kmph (130-140 knots) as it makes its final approach, something which can easily be impacted by variable wind conditions over the deck of the ship. To experience these conditions, test pilots will perform several touch-and- goes on the deck of the Vikramaditya, where they land on the ship but immediately take off without coming to a full stop. A full-fledged arrested landing on the aircraft carrier will only happen once test pilots are certain of the stability of the fighter in making its landing approach and their ability to hold a constant speed as they come in to land.

There is another, major technical concern which could impact the development of the LCA-N. The arrestor gear on INS Vikramaditya, the mechanical system used to rapidly slow down an aircraft as it lands, has key design differences from the gear installed at the Shore Based Test Facility where the LCA-N is now being tested. Key members of the LCA-N project team are hopeful that this does not impact the project but they will not be certain until they actually land on the ship.…"

Photo: "Light Combat Aircraft-Navy landing at the Shore Based Test Facility in Goa, a replica of the deck of the Navy's aircraft carrier, INS Vikramaditya" https://c.ndtvimg.com/2019-06/o10p5o1_l ... une_19.jpg


Source: https://www.ndtv.com/india-news/landing ... ne-2051358

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 24 Jun 2019, 01:16
by Corsair1963
It would be crazy for India to pursue the development of the N-LCA any further. As it would be obsolete by time it "ever" reached service. Plus, I hardly see a need for the type in the first place. Especially, since the Indian Navy already operates the Mig-29K. While, looking to purchase an additional 57 Western Naval Fighters.

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 24 Jun 2019, 04:43
by Corsair1963
Oh, and the small size of the N-LCA hardly makes it ideal for Carrier Operations. (i.e. poor Range/Payload)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 06:37
by Corsair1963
Does anybody know of a source. That states Ski Jumps are less stressful on Naval Aircraft than Catapults???

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 06:43
by steve2267
Corsair1963 wrote:Does anybody know of a source. That states Ski Jumps are less stressful on Naval Aircraft than Catapults???


Zero to 165mph in two seconds...

vs

Zero to flying speed in 5-6 seconds?

For real?

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 06:47
by steve2267
QS also has a post around here in the past coupla months about all the additional structure (i.e. weight) required in an aircraft, not just in the nose strut, but in the keel from the nose back into the rest of the aircraft fuselage. Only going to need all that extra metal to handle the additional stresses. Does that meet your needs?

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 06:52
by spazsinbad
Corsair1963 wrote:It would be crazy for India to pursue the development of the N-LCA any further. As it would be obsolete by time it "ever" reached service. Plus, I hardly see a need for the type in the first place. Especially, since the Indian Navy already operates the Mig-29K. While, looking to purchase an additional 57 Western Naval Fighters.

LCA N is going to be the Indian Navy training aircraft perhaps. Another thread says the Indian Navy require a twin engine aircraft yet to be finalised / developed: viewtopic.php?f=58&t=53865&p=434397&hilit=Tejas#p434397 This thread has posts about such twin-engine deck-based fighter (TEDBF) matters.

Another aspect of ski jump capable aircraft is the undercarriage. Initially the Harrier undercart was not ideal. Also EMALS was developed TO BE LESS STRESSFUL on catapult aircraft than GODDAMN STEAM! :roll:

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 07:05
by Corsair1963
I've said for sometime now. That India should develop the LCA into an "advanced trainer" for the Indian Air Force and/or Navy. If, she must pursue the type...(i.e. for political reasons)

Yet, honestly I don't even see the funding for that! :shock:

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 10 Feb 2020, 07:06
by Corsair1963
steve2267 wrote:
Corsair1963 wrote:Does anybody know of a source. That states Ski Jumps are less stressful on Naval Aircraft than Catapults???


Zero to 165mph in two seconds...

vs

Zero to flying speed in 5-6 seconds?

For real?


NO I wasn't questioning it at all. Just looking for a source to support it....

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 13 Feb 2020, 02:45
by steve2267
There's your source.

Or you could state the math yourself. You just inquired about "lower" -- not actual g-values. So the math should fairly obviously show it to be lower. Or perhaps support your statement / math by quoting sources about how long it takes to STO off an LHA vice catapult velocity / time values (which are easy to find).

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 13 Feb 2020, 08:19
by spazsinbad
Look through this PDF: SKI JUMP INFO VARIOUS Sep 2015 pp152 forumED.pdf (11Mb)

download/file.php?id=25188

OR attached F-35B STO & CVF Ski Jump INFO 30NOV17 pp147

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 13 Feb 2020, 13:02
by spazsinbad
CARRIER SUITABILITY OF LAND-BASED AIRCRAFT [PDF attached below]
25 Jun 2012 José-Luis Hernando and Rodrigo Martínez-Val Universidad Politécnica de Madrid

Abstract
The paper describes the first steps of a study aimed at assessing the modifications that should be introduc-ed in ground-based combat airplanes to make them compatible with aircraft carriers designed with ski-jumps & arresting devices. The present analysis includes operational and performance aspects, & describes the complexity of the take-off and approach/landing manoeuvres, identifying the key variables intervening in such manoeuvres. A last section is devoted to summarise the most critical features for carrier suitability....

...4 Final considerations
The present paper has described the take-off and approach/landing manoeuvres, as they are performed on aircraft carriers equipped with ski-jumps and arresting mechanisms. The operations are very different from those on ordin-ary runways, for the size and longitudinal motion of the deck, for the pitch and heave displacements of the carrier, and for the potential interference between the carrier superstructure wake or the rough sea generated air turbulence and the approach glide path. The findings include the following critical items:

- The thrust-to-weight ratio at take-off must be appropriately matched to the available deck length & the ski-jump geometry, including wind-on-deck effects;
- The approach speed must be compatible with wind-on-deck & the available landing distance to completely stop the airplane after engaging the last arresting pendant;
- The thrust-to-weight ratio at approach must be high enough as to allow fast acceleration and safe lift-off should the airplane hook failing engaging the arresting pendants.

Obviously, since the present paper only describes the first steps of the study there are other important aspects that will be addressed in future works. They include, for example:

- Very fast control to give the pilot full authority on the aircraft after the semi ballistic jump at the end of a hands-off take-off;
- Suitable aircraft attitude during ground runs, that may require meaningful modifications of the nose landing gear; and
- Rear fuselage modifications to fit the arresting hook, as well as structural reinforcements to withstand the hook transmitted loads.”

Source: http://www.icas.org/ICAS_ARCHIVE/ICAS20 ... RS/167.PDF (1Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 17 Feb 2020, 00:06
by spazsinbad
More on HORNET on Ski Jump test NAN Mar-Apr 1984: https://www.history.navy.mil/research/h ... april.html (PDF 4.4Mb)

Re: F-35B/C and the Ski-Jump?

Unread postPosted: 17 Feb 2020, 04:16
by Corsair1963
THANKS