By Tommy H. Thomason

Wednesday, October 14, 2009

It Seemed Like a Good Idea at the Time V

The Vought F7U-1 was one of the more gimmicky designs ever to fly. Some of the wonderfulness came directly from it being "tail-less", which sounds like a simplification but introduced complications from a carrier landing standpoint. An airplane with no horizontal tail can't have trailing edge flaps, since there's no way to counteract the nose down pitching moment that flap extension causes. No flaps means a high approach speed, which was unacceptable for a carrier-basing, unless the airplane has lots of wing area and/or approaches at a high angle of attack. In order to minimize the former, Vought relied more on the latter. The high nose attitude resulted in a long nose gear. To reduce the rearward loading on the nose gear strut attachment when the nose wheel touched down, the wheel was spun up to speed before landing by compressed air from the engine impinging on a set of vanes on the nose wheel hub. The main gear could be set in either of two positions, forward for takeoff and aft for landing. And the tail hook was attached to the top of the fuselage, so the nose would not pitch down when the hook engaged a cross-deck pendant. This resulted in the hook being stowed on the top of the aft fuselage instead of the bottom, which meant that it was longer than usual. That led to a three-segment hook that folded back on itself for stowage.

It's difficult to see in either the illustration or the photo, but the most forward segment of the hook  was a V-frame. It was covered by a pair of triangular doors. When the hook was extended, it was retained in its stowed position by a latch until the hook engaged a cross-deck pendant and then was released to pivot in line with the two hook segments aft of it.

As if that weren't complicated enough, the hook throat included another Vought innovation, a "trigger" that forcibly ejected the cross-deck pendant after the aircraft was stopped to insure that the hook released the pendant. If it didn't, a sailor had to run out and knock it loose so the airplane could taxi out of the landing area.

During shore-based trials at Pax, the rectangular fairing over the aft hook segment came off during three arrestments, so it was reattached to the V-frame and hinged to the side to allow the hook to extend. The pendant ejector was deleted "in an effort to simplify the arresting hook assembly." The whole experience was summarized with the statement: "The arresting hook assembly is complicated, and its practicability for service use is doubtful."

The F7U-3 had a conventional V-frame hook attached to bottom of the aft fuselage.

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