The Convair F2Y Sea Dart was an American seaplane fighter aircraft that rode on twin hydro-skis during takeoff and landing. It flew only as a prototype, and never entered mass production. It is the only seaplane to have exceeded the speed of sound.
It was created in the 1950s, to overcome the problems with supersonic planes taking off and landing on aircraft carriers. The program was canceled after a series of unsatisfactory results and a tragic accident on 4 November 1954, in which test pilot Charles E. Richbourg was killed when the Sea Dart he was piloting disintegrated in midair. The four surviving planes were retired in 1957, but some were kept in reserve until 1962.
The Sea Dart began as Convair's entry in a 1948 U.S. Navy contest for a supersonic interceptor aircraft. At the time, there was much skepticism about operating supersonic aircraft from carrier decks. In order to address this issue, the U.S. Navy ordered many subsonic fighters. The worry had some foundation, since many supersonic designs of the time required long takeoff rolls, had high approach speeds, and were not very stable or easy to control—all factors that were troublesome on a carrier.
Ernest Stout's team at Convair's hydrodynamic research laboratory proposed to put a Delta Dagger on water skis.
he aircraft was built in Convair's San Diego facility at Lindbergh Field and was taken to San Diego Bay for testing in December 1952. On 14 January 1953, with E. D. "Sam" Shannon at the controls, the aircraft inadvertently made its first short flight during what was supposed to be a fast taxi run; its official maiden flight was on 9 April.
An XF2Y-1 in flight
The underpowered engines made the fighter sluggish, and the hydro-skis were not as successful as hoped; they created violent vibration during takeoff and landing, despite the shock-absorbing oleo legs they were extended on. Work on the skis and legs improved this situation somewhat, but they were unable to resolve the sluggish performance. The Sea Dart proved incapable of supersonic speed in level flight with the J34 engines; not helping was its pre-area rule shape, which meant higher transonic drag.
General characteristics
Crew: 1
Length: 51 ft 1.5 in (15.583 m)
Wingspan: 35 ft 4 in (10.77 m)
Width: 5 ft 5 in (1.65 m) fuselage / hull beam
Draught (skis retracted): 40 in (1,000 mm)
Draught (skis extended): 96.5 in (2,450 mm)
Height: 16 ft (4.9 m) on 3-point beaching gear
7 ft 5 in (2.26 m) aircraft in horizontal rigging position
Wing area: 568 sq ft (52.8 m2)
Aspect ratio: 1.02
Airfoil: root: NACA 0003.30-65 (mod.) 3% thickness ; tip (station 173.7): NACA 0004-65 (mod.) 4% thickness ; average thickness 3.83%
Empty weight: 16,725 lb (7,586 kg)
Gross weight: 24,373 lb (11,055 kg)
Fuel capacity: 1,000 US gal (830 imp gal; 3,800 l) usable fuel + 6.5 US gal (5.4 imp gal; 25 l) unusable fuel
Powerplant: 2 × Westinghouse J46-WE-12B afterburning turbojet engines, 4,500 lbf (20 kN) thrust each dry, 6,100 lbf (27 kN) with afterburner
XF2Y-1 137634 2x Westinghouse J34-WE-32 3,400 lbf (15,000 N) (dry only)
Performance
Maximum speed: 695 mph (1,118 km/h, 604 kn) at 8,000 ft (2,400 m)
825 mph (717 kn; 1,328 km/h) at 36,000 ft (11,000 m)
Maximum speed: Mach 1.25
Range: 513 mi (826 km, 446 nmi)
Rate of climb: 17,100 ft/min (87 m/s)
Time to altitude: 35,000 ft (11,000 m) in 1 minute 42 seconds
Wing loading: 29 lb/sq ft (140 kg/m2)
Thrust/weight: 0.56 (max. loaded); 0.96 (empty)
Take-off run: 5,500 ft (1,700 m)
Landing run: 1,500 ft (460 m)
Take-off time in calm air: 35 seconds
Landing speed at 20° alpha: 130 mph (113 kn; 209 km/h) in landing configuration with 10% fuel
Armament
Guns: 4x fixed forward-firing 20 mm (0.787 in) Colt Mk 12 cannon (production aircraft)
Rockets: Fin-Folding Aerial Rockets (production aircraft)
Missiles: 2 × air-to-air missiles (production aircraft)
The second prototype was canceled, so the first service test aircraft was built and flown. This was fitted with the J46 engines, which performed below specification. However, speeds in excess of Mach 1 were attained in a shallow dive with this aircraft, making it the only supersonic seaplane to date. On 4 November 1954, Sea Dart BuNo 135762 disintegrated in midair over San Diego Bay during a demonstration for naval officials and the press, killing Convair test pilot Charles E. Richbourg when he inadvertently exceeded the airframe's limitations. Richbourg was a 31-year-old Navy veteran of the Second World War. He was quickly pulled from the water but did not survive the airframe breakage. He was buried in St. Augustine National Cemetery in Florida.
Footage courtesy of the San Diego Air and Space Museum Archives
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