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

Corsair1963 · by **Corsair1963** » 27 May 2010, 06:24

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?

spazsinbad · by **spazsinbad** » 27 May 2010, 09:01

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."

bjr1028 · by **bjr1028** » 27 May 2010, 16:03

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.

Corsair1963 · by **Corsair1963** » 31 May 2010, 03:52

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......

spazsinbad · by **spazsinbad** » 31 May 2010, 04:25

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.

sextusempiricus · by **sextusempiricus** » 31 May 2010, 04:31

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:

madrat · by **madrat** » 31 May 2010, 04:43

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.

Corsair1963 · by **Corsair1963** » 31 May 2010, 04:44

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.

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:

spazsinbad · by **spazsinbad** » 31 May 2010, 05:14

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

spazsinbad · by **spazsinbad** » 31 May 2010, 05:19

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.

spazsinbad · by **spazsinbad** » 31 May 2010, 05:48

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

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

Corsair1963 · by **Corsair1963** » 31 May 2010, 06:07

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???

spazsinbad · by **spazsinbad** » 31 May 2010, 06:22

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.

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

spazsinbad · by **spazsinbad** » 31 May 2010, 07:48

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...."

spazsinbad · by **spazsinbad** » 31 May 2010, 08:47

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."