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

Discuss the F-35 Lightning II
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spazsinbad

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Unread post31 May 2010, 09:24

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.
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Unread post31 May 2010, 10:45

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.
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Unread post31 May 2010, 10:50

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.
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Unread post31 May 2010, 12:42

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.
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Unread post31 May 2010, 13:07

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)
Last edited by spazsinbad on 31 May 2010, 13:21, edited 1 time in total.
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Unread post31 May 2010, 13:20

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.
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Unread post31 May 2010, 13:34

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
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Rafale Ski Jump test US FlightInternational 1991 - 2611ED.gif
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Unread post31 May 2010, 15:04

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

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Unread post31 May 2010, 21:33

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).
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Unread post31 May 2010, 22:58

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
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Unread post01 Jun 2010, 03:10

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.
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CV with Monorail Launch system
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Unread post01 Jun 2010, 03:47

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
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Unread post01 Jun 2010, 03:53

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.
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Unread post01 Jun 2010, 20:35

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.
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Unread post01 Jun 2010, 21:41

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:
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
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