Leteči brodovi... :: Nauka ~ Tehnika ~ Military

Convair F2Y Sea Dart

The Convair F2Y Sea Dart was a unique American seaplane fighter jet aircraft that rode on twin hydro-skis for takeoff. It only flew as a prototype, and never entered production, but it is still the only seaplane to exceed the speed of sound.The Sea Dart began as Convair's entry to a 1948 Navy contest for a supersonic interceptor aircraft. There was at the time much scepticism about operating supersonic planes from aircraft carrier decks, which explains why the US Navy ordered so many subsonic fighters at that time. The worry had some foundation, since many supersonic designs of the time required long takeoff rolls and had high approach speeds, and were not very stable or easy to control - all factors that were troublesome on a carrier.

Convair's proposal gained an order for two prototypes in late 1951. The aircraft was to be a delta-winged fighter with a watertight hull with twin retractable hydro-skis for takeoff and landing. When stationary or moving slowly in the water, the Sea Dart floated with the trailing edge of the wings touching the water. The skis were not extended until the aircraft reached about 10 mph (16 km/h) during its takeoff run.

Twelve production aircraft were ordered before a prototype had even flown. No armament was ever fitted to any Sea Dart built, but the plan was to arm the production aircraft with four 20 mm cannon and a battery of folding-fin unguided rockets.Four of this order were redesignated as service test planes, and an additional eight production planes were soon ordered as well.

Power was to be a pair of afterburning Westinghouse XJ46-WE-02 turbojets, fed from intakes mounted high above the wings to avoid ingesting spray. These engines were not ready for the prototypes and twin Westinghouse J34-WE-32 engines of just over half the power were installed.The aircraft were built in Convair's San Diego facility at Lindbergh Field and was taken to San Diego Bay for testing. On 14 January 1953 the aircraft with E. D. "Sam" Shannon at the controls, inadvertently made its first short flight during what was supposed to be a fast taxi run; its official maiden flight was on 9 April.

The underpowered engines made the plane 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 oleo legs improved this situation somewhat, but they could not cure the sluggish performance. The Sea Dart proved incapable of supersonic speed in level flight with those engines; not helping was its pre-area rule shape, which meant higher transonic drag.

The second prototype was cancelled, so the first service test aircraft was next to build and fly. This one 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. This plane disintegrated in mid-air during a demonstration to Navy officials and the press, killing Convair test pilot, Charles E. Richbourg.All four remaining Sea Darts survive to this day. The prototype is awaiting restoration for the Smithsonian Institution, and is in bad shape. The others are at the San Diego Aerospace Museum, the Wings of Freedom Air and Space Museum at Willow Grove, Pennsylvania, and at the Lakeland, Florida airport.
# Crew: 1
# Length: 52 ft 7 in (16 m)
# Wingspan: 33 ft 8 in (10.3 m)
# Height: 16 ft 2 in (4.9 m)
# Wing area: 568 ft² (53 m²)
# Empty weight: 12,625 lb (5,730 kg)
# Loaded weight: 16,500 lb (7,480 kg)
# Max takeoff weight: 21,500 lb (9,750 kg)
# Powerplant: 2× Westinghouse J46-WE-2 {testbed: J43-WE-32 w/ 3,400 lbf each. * Maximum speed: 825 mph (1,325 km/h) * Range: 513 mi (446 nm, 826 km) * Service ceiling: 54,800 ft (16,700 m) * Rate of climb: 17,100 ft/min (86.7 m/s) * Wing loading: 29.0 lb/ft² (142 kg/m²) * Thrust/weight: 1.45