Forum: F-35 Lightning II

Japan also did one (Asuka STOL prototype):

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Because I like engineers so much some text from the U-2 Carrier Landing PDF mentioned in this thread is below. Best to read the entire PDF (this is only what really interested me). SEE TOP OF PAGE 2 of THIS THREAD:

U-2 Aircraft Carrier Operation | project “Whale Tale”

http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB184/FR24.pdf (1Mb)

"The first tests of a U-2 on an aircraft carrier were undertaken in August of 1963. For the preliminary tests a conventional (unmodified) U-2 was used. The operation was designated “Project WHALE TALE.”

On the night of 2 August, an Agency U-2 was flown to North Island Naval Air Station at San Diego, California, where, under cover of darkness, and after midnight, it was loaded aboard the Aircraft Carrier USS KITTY HAWK and stowed below decks in the hangar bay....

...The KITTY HAWK was underway at 20 knots; this, combined with a 10 knot headwind resulted in a 30 knot wind across the flight deck. The impressive wing span and light construction of the U-2 under these conditions gave the maintenance crew some difficulty in holding the aircraft on the deck, even without application of power. On signal, the U-2 with LAC test pilot, at the controls started its take-off run down the fllght deck. As the throttle was advanced, the 16,000 pound thrust Pratt & Whitney J-75 engine catapulted the U-2 toward the bow of the ship. ln approximately one third the length of the flight deck the aircraft was airborne, the pogos fell away, and by the time the U-2 cleared the bow it was already approximateiy 1,000 teet above the carrier. Then, with pardonable exhibitionism, Schumacher racked the U-2 into a steep climb — a breath-taking spectacle to anyone who had never previously witnessed a U-2 take-off climb under full power. To the carrier crew, accustomed to the flat trajectory take-off of the heavier and more conventional carrier-based aircraft, the U-2 maneuver was a new and somewhat startling experience....

...On 28 February 1964, Lockheed and Detachment personnel and equipment were loaded aboard the RANGER. On the following morning, the RANGER proceeded to the test area off San Diego where the operations were to be conducted. Phase One began with LAC pilot flying aircraft number 362 in a series of touch-and-go landings on the RANGER. The touch-and-go landings all went smoothly; however, on the first attempt for a hook engagement landing, the aircraft bounced and the hook engaged the wire while the aircraft was in the air. This caused the aircraft to be slammed back on deck and nose over. Minor damage resulted to the nose section of the aircraft which was taken below deck for repairs. After repairs were completed, the aircraft was flown back to Durbank for the instrumentation read out. As a result of this Incident, Phase One was rescheduled for 2 March 1964.

On 2 March, LAC pilot returned to the RANGER in aircraft 348 and completed four successful arrested landings....
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"Aside from the unknown range and altitude characteristics of the converted aircraft (which will depend upon arresting gear weight for the most part), the only apparent aerodynamic question is associated with the behavior of the aircraft in the landing configuration. when it is approachIng a fast moving carrier from the stern. One suggestion which has been made is that the standard angle of attack for such an approach with Navy aircraft which is three or four degrees to the horizontal be reduced to approximately 1 1/2 to 2 degrees in the case of the U-2 to permit a flatter angle of approach with power on so that “ballooning” of the aircraft prior to contact with the deck wlll be minimized.

"In a normal landing attitude, the U-2 rides tail high, which unless compensated for by a skillful power-on approach just above the stall speed may make the engagement of a carrier hook relatively difficult. There is a possibility that a problem may exist in wind pattern over the stern of a fast moving carrier, which according to Navy statistics, normally produces a down-draft immediately to the rear of the stern, followed by an up-draft from 1,000 to 1,500 feet aft of the carrier. With its sizeable wing area and with flaps fully extended, there may be some adjustments in technique which will have to be accomplished in order to overcome the possible adverse effects of these phenomena.

“Stack wash from the carrier’s funnels can largely be eliminated as a deterrent characteristic, since carriers on which the U-2 would be landed make their arrested landings on the angled deck, approximately nine degrees from the central axis of the hull away from the island, and the captains of both the USS LEXINGTON and USS INDEPENDENCE stated categorically that they ‘could put the stack wash wherever the pilot wanted it.’ This, of course, means that they could adjust the carrier’s steaming angle to take maximum advantange of existing wind conditions to deflect stack wash. The only time this might be a modest problem would be when the aircraft is landed in a no wind condition, at which time it must rely solely on the carrier’s forward momentum for relative wind.”...

...The principal configuration change incorporated in the U-2G in order to enable it to operate effectively from carriers included a mechanically operated fuel jettison system too permit the aircraft to be reduced to maximun gross landing weight in the event of either an inflight emergency requiring an immediate landing or in those cases where the aircraft is returned to the ship from a mission with fuel to spare. A further modification was the incorporation of a heavier landing gear which effectively more than doubled the original design specification of maximum deceleration in terms of feet per second. Coupled with this beefed-up landing gear were heavier pressure bulkheads in the landing gear section and augmented longerons in the fuselage at the trailing edge of the wing to withstand the added impact of carrier hook engagement. A modified T2V arresting hook was installed in the aircraft, covered by a plastic fairing which reduces aerodynamic drag, and which is jettisoned at the time the aircraft enters the traffic pattern around the carrier preparatory to landing.

The single most important modification, however, was the addition of a pair of mechanical spoilers situated midway outboard on the trailing edge of each wing. These are activated by a simple switch on the throttle quadrant. Upon actuation at the point of touch-down of the aircraft the wing stalls almost immediately, enabllng the pllot to spot-land with nearly the same accuracy that would be encountered in more conventional aircraft. Light weight, one inch arresting cables have been substituted for the normal heavier arresting cables on the CVAs in order to reduce critical vibration encountered when the aircraft runs over the cables in the process of arrestment.

It subsequently proved necessary to depress the Fresnel lens landing system to an angle of 1.5 degrees to give the pilot of the U-2 a proper representation of the “meatbaIl” during his final approach to the deck. Experience has shown that under normal landing conditions with an approach speed of approximately 82 knots and wind from 26 to 30 knots wind across the flight deck, effective arrestments at a relative speed of 50-55 knots can be obtained with the ship's arresting engines set at the lowest available figure of only 10,000 pounds of force. All takeoffs from the carrier with the U-2 are normally made on the axial as opposed to the angle deck which requires a clear deck forward in all cases. Catapult launch of the U-2G is not feasible for structural reasons."

Forum: F-35 Lightning II

A brief history of tailhook design