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

[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.

[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.

[quicksilver]

Deleted. Wrong thread.

[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."

[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

[sferrin]

They've been working on that thing forever.

[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)

[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)

[f35phixer]

starting soon real soon !!!!

[bring_it_on]

starting soon real soon !!!!

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

[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

[f35phixer]

starting soon real soon !!!!

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

a STOVL jet doing testing.

[spazsinbad]

MAGIC - thanks 'f35phixer' - great news. Apparently at AeroIndia soon info about the OLS will be available.

[KamenRiderBlade]

Am I the only one who feels India's new natively produced fighter looks ALOT like the "Mirage 2000"?

[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°.