johnbr
2nd Lieutenant
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Vought XF5U "Flying Pancake
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johnbr
2nd Lieutenant
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johnbr
2nd Lieutenant
Design and development Vought Website
The XF5U-1 was designed as a land-based or carrier-based fighter to be used with or without a catapult, with an arresting gear. The airplane incorporated certain unusual design and structural features.
The wing, the basic outline of which was defined by two ellipses, so arranged that the major axis of one coincided with the minor of the other, comprised the main structure of the airplane, with the exception of the pilot's cockpit and the horizontal and vertical tail surfaces. The greater part of the wing surfaces and internal structure was composed of Metalite, a "sandwich" material providing a particularly strong and light type of construction. The four-bladed counter-rotating propellers were driven by cross-shafting and gear boxes connected to both engines. If one engine failed, it could be de-clutched from the system and the airplane flown with the remaining engine and both propellers operating. Circular air intakes in the wing leading edge provided carburetor, engine and oil cooling air. Two vertical tails with rudder and fins provided directional control. Two Metalite ailavators, with trim tabs across 70% of their trailing edge and with balance weights on the tips, provided lateral and longitudinal control. The pilot's cockpit was a complete monocoque shell with a formed plexiglass canopy. The stick and rudder flight controls were manual except for proportional hydraulic boost to the ailavators.
Neither the first nor second airplane had armament, although there were provisions for six 50-caliber machine guns and ammo boxes. Two Pratt and Whitney R-2000-7 radial engines with cooling fans and superchargers were mounted upright in the wing.
The 16-foot diameter propellers were unique for the time and bear some mention. Because of the activity factor, twist and shape, the props were manufactured by Chance Vought Aircraft of Stratford, Connecticut. The two hydraulically operated, fast-acting, electro-mechanically governed propellers each had four Pregwood blades and load-relieving hubs which differed from the conventional four-way hub in that the blades were free to "flap" in pairs about the shaft axis. Low pitch stop was 15 degrees, high pitch stop was 70 degrees. The propeller pitch control set the left-hand propeller governor mechanism which controlled the right-hand propeller governor mechanism electronically and adjusted the propeller blade angle. Movement of the pitch control lever upward decreased pitch, and downward increased the pitch. Full forward position governed takeoff rpm (2,700): full aft position gave approximately 1,300 rpm in take-off slot and 800 rpm for flight. These were propeller rpm's. There was also the more conventional throttle control which operated in three slots: "WARM-UP", "TAKE-OFF" and "FLIGHT".
Another unique feature of the XF5U-1 was the stability flap, located symmetrically about the centerline of the airplane at the wing trailing edge. The 15 sq. ft. hinged surface required no pilot control but automatically provided for change in airplane trim with change in attitude. The air loads upon the flap adjusted deflection against a spring loaded strut. The stability flap was linked to the tail wheel to insure locking in the up position when the tail wheel was extended.
The XF5U-1 was designed as a land-based or carrier-based fighter to be used with or without a catapult, with an arresting gear. The airplane incorporated certain unusual design and structural features.
The wing, the basic outline of which was defined by two ellipses, so arranged that the major axis of one coincided with the minor of the other, comprised the main structure of the airplane, with the exception of the pilot's cockpit and the horizontal and vertical tail surfaces. The greater part of the wing surfaces and internal structure was composed of Metalite, a "sandwich" material providing a particularly strong and light type of construction. The four-bladed counter-rotating propellers were driven by cross-shafting and gear boxes connected to both engines. If one engine failed, it could be de-clutched from the system and the airplane flown with the remaining engine and both propellers operating. Circular air intakes in the wing leading edge provided carburetor, engine and oil cooling air. Two vertical tails with rudder and fins provided directional control. Two Metalite ailavators, with trim tabs across 70% of their trailing edge and with balance weights on the tips, provided lateral and longitudinal control. The pilot's cockpit was a complete monocoque shell with a formed plexiglass canopy. The stick and rudder flight controls were manual except for proportional hydraulic boost to the ailavators.
Neither the first nor second airplane had armament, although there were provisions for six 50-caliber machine guns and ammo boxes. Two Pratt and Whitney R-2000-7 radial engines with cooling fans and superchargers were mounted upright in the wing.
The 16-foot diameter propellers were unique for the time and bear some mention. Because of the activity factor, twist and shape, the props were manufactured by Chance Vought Aircraft of Stratford, Connecticut. The two hydraulically operated, fast-acting, electro-mechanically governed propellers each had four Pregwood blades and load-relieving hubs which differed from the conventional four-way hub in that the blades were free to "flap" in pairs about the shaft axis. Low pitch stop was 15 degrees, high pitch stop was 70 degrees. The propeller pitch control set the left-hand propeller governor mechanism which controlled the right-hand propeller governor mechanism electronically and adjusted the propeller blade angle. Movement of the pitch control lever upward decreased pitch, and downward increased the pitch. Full forward position governed takeoff rpm (2,700): full aft position gave approximately 1,300 rpm in take-off slot and 800 rpm for flight. These were propeller rpm's. There was also the more conventional throttle control which operated in three slots: "WARM-UP", "TAKE-OFF" and "FLIGHT".
Another unique feature of the XF5U-1 was the stability flap, located symmetrically about the centerline of the airplane at the wing trailing edge. The 15 sq. ft. hinged surface required no pilot control but automatically provided for change in airplane trim with change in attitude. The air loads upon the flap adjusted deflection against a spring loaded strut. The stability flap was linked to the tail wheel to insure locking in the up position when the tail wheel was extended.
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johnbr
2nd Lieutenant
Front view. The propeller blades were
black from the root with white stenciling,
then varnished mahogany with yellow tips.
The right propeller had Hamilton Standard
oval decals and both propellers had small white "tracking" diamonds on them.
The letter of intent for the Vought VS-315 (XF5U-1) was issued September 17, 1942. The XF5U-1 was a twin-engine, single-seat, low aspect ratio flying wing type of airplane, manufactured by the Chance Vought Division, United Aircraft Corporation, Stratford, Connecticut.
The first XF5U-1 airplane (Bureau Number 33958) was used for static tests; proof loads, extended to ultimate, largely confirmed structural design predictions. The second XF5U-1 airplane (Bureau Number 33959) was used for experimental flight test and concept validation. It was never flown because many hours of engine run-up showed excessive mechanical vibration between the engine-propeller shafting, gear boxes, and airframe structure. The airplane was taxi tested on February 3, 1947 at Stratford, Connecticut, but, again, vibration levels were considered excessive.
The airplane was being readied for shipment by sea through the Panama Canal to Edwards AFB, California, when the contract was canceled (March 17, 1947) because of still unsolved technical problems and the lack of Navy R&D money
black from the root with white stenciling,
then varnished mahogany with yellow tips.
The right propeller had Hamilton Standard
oval decals and both propellers had small white "tracking" diamonds on them.
The letter of intent for the Vought VS-315 (XF5U-1) was issued September 17, 1942. The XF5U-1 was a twin-engine, single-seat, low aspect ratio flying wing type of airplane, manufactured by the Chance Vought Division, United Aircraft Corporation, Stratford, Connecticut.
The first XF5U-1 airplane (Bureau Number 33958) was used for static tests; proof loads, extended to ultimate, largely confirmed structural design predictions. The second XF5U-1 airplane (Bureau Number 33959) was used for experimental flight test and concept validation. It was never flown because many hours of engine run-up showed excessive mechanical vibration between the engine-propeller shafting, gear boxes, and airframe structure. The airplane was taxi tested on February 3, 1947 at Stratford, Connecticut, but, again, vibration levels were considered excessive.
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johnbr
2nd Lieutenant
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johnbr
2nd Lieutenant
a real odd one that's for sure.
Good shots!
To prevent wear during the many hours of ground running the rotors were replaced with standard Hamilton Standard four blade props. Because there wasn't a left hand version of this propeller the blades on the left prop were reversed so that it gave reverse thrust, the close-up view of this prop in the second photo of post #1 (wider view post #3 pic 5) shows this as well as any photo I've seen. The reference in post #9 about Hamilton Standard decals only being on the right (forward) propeller may simply not account for the likelihood of decals being on the aft facing side of the left propeller blades.
This aircraft had the same flight safety requirement of requiring both rotors to keep turning in an engine out situation as the V-22 Osprey and we all know how troubled that development process was. In a practical sense the aircraft was doomed before development started.
This aircraft had the same flight safety requirement of requiring both rotors to keep turning in an engine out situation as the V-22 Osprey and we all know how troubled that development process was. In a practical sense the aircraft was doomed before development started.
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johnbr
2nd Lieutenant
The Vought XF5U "Flying Pancake" was an experimental fighter aircraft designed by NACA researcher Charles H. Zimmerman. This unorthodox design consisted of a flat, somewhat disc shaped body serving as the lifting surface, with propellers located on the leading edge at the wingtips. The XF5U-1 was a larger version of the original #V-173 (see alsoV-173 testing).
The project was cancelled in 1947 and the lone V-173 prototype transferred to the Smithsonian Institute.
Old Wizard
2nd Lieutenant
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johnbr
2nd Lieutenant
Assembly breakdown.
