Convair F2Y Sea Dart

F2Y Sea Dart
F2Y Sea Dart (dual-ski configuration)
Role	Seaplane fighter
Manufacturer	Convair
First flight	14 January 1953
Retired	1957
Status	Cancelled, museum storage
Primary user	United States Navy
Number built	5

The Convair F2Y Sea Dart was a unique American seaplane fighter 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.^{[citation needed]}

Development

The Sea Dart began as Convair's entry to a 1948 U.S. Navy contest for a supersonic interceptor aircraft. There was at the time much skepticism about operating supersonic aircraft from aircraft carrier decks, which explains why the U.S. 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. 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 (.79 in) cannon and a battery of folding-fin unguided rockets.^[1] Four of this order were redesignated as service test vehicles, and an additional eight production aircraft were soon ordered as well.

Design

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.

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.

Ski configurations

The sole remaining prototype was fitted with an experimental single-ski configuration which proved to be more successful, while the second service test aircraft trialled (unsuccessfully) a new twin-ski design. Testing with several other experimental ski configurations continued with the prototype through 1957, after which it was placed into storage.

The US was not the only country to consider the hydroski. The Saunders-Roe company of the United Kingdom, who had already built an experimental flying-boat jet fighter, tendered a design for a ski equipped fighter but little came of it.

Submarine carriage

In the 1950s, the US Navy considered the internal arrangements of a submarine that could carry three of these aircraft. Stored in pressure chambers that would not protrude from the hull, they would be raised by a portside elevator just abaft the conning tower (or sail) and set to take off on their own on a smooth sea but catapulted aft in a higher sea. The program only reached the "writing on a napkin" stage, for two problems were not addressed: the hole for the elevator would have seriously weakened the hull and the load of a laden elevator would also be difficult to transmit to the hull structure.^[2]

Operational history

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.

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 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 the J34 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. On 4 November 1954, Sea Dart, BuNo 135762, disintegrated in mid-air over San Diego Bay, California, during a demonstration for Navy officials and the press, killing Convair test pilot Charles E. Richbourg when he inadvertently exceeded the airframe limitations.^[3]

Even before that, the Navy had been losing interest (problems with supersonic fighters on carrier decks having been overcome) and the crash relegated the Sea Dart program to experimental status. All production aircraft were cancelled, though the remaining three service test examples were completed. The two final prototypes never flew.

Redesignation

Despite the fact that the airplane was officially retired and had not flown since 1957, at least one F2Y was still in storage as of 1962. As a result, it was re-designated as the F-7 under the 1962 United States Tri-Service aircraft designation system.^[4]

Operators

 United States

• United States Navy

Aircraft on display

Sea Dart at the San Diego Aerospace Museum

All four remaining Sea Darts survive to this day.

• XF2Y-1 Sea Dart, Bureau Number 137634, is in bad shape and is awaiting restoration for the Smithsonian Institution in Washington D.C..
• YF2Y-1 Sea Dart, Bureau Number 135763, is on display at the San Diego Aerospace Museum in the Balboa Park area of San Diego, California. It is on loan from the National Museum of Naval Aviation at NAS Pensacola.
• YF2Y-1 Sea Dart, Bureau Number 135764, is on display at the Wings of Freedom Aviation Museum at NAS Willow Grove, Pennsylvania. It is on loan from the National Museum of Naval Aviation at NAS Pensacola.
• YF2Y-1 Sea Dart, Bureau Number 135765, is on display at the Florida Air Museum that is part of the Sun 'n Fun complex at Lakeland Linder Regional Airport, Florida. It is on loan from the National Museum of Naval Aviation at NAS Pensacola.

Specifications (F2Y-1)

General characteristics

• 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.^[5]} turbojets, 6,100.^[6] lbf (27 kN) each

Performance (estimated^[7])

• 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: .56 (max loaded).96 (empty)

Armament

• Guns: 4 × 20 mm (0.79 in) cannon
• Rockets: Unguided rockets
• Missiles: 2 × air-to-air missiles

See also

Related development

• Convair XF-92
• F-102 Delta Dagger
• F-106 Delta Dart
  

Aircraft of comparable role, configuration and era

• Saunders-Roe SR.A/1
  

Related lists

• List of flying boats and seaplanes
• List of military aircraft of the United States (naval)
  

References

Notes

1. ^ Winchester 2005, p. 105.
2. ^ Friedman, Norman. U.S. Submarines Since 1945: An Illustrated Design History. Annapolis, MD: Naval Institute Press, 1995. ISBN 1-55750-263-3.
3. ^ Jackson, Robert, "Combat Aircraft Prototypes since 1945", Arco/Prentice Hall Press, New York, New York, 1986, Library of Congress card number 85-18725, ISBN 0-671-61953-5, page 161.
4. ^ Parsch, Andreas. "Aircraft Redesignations in 1962." designation-systems.net, 2007. Retrieved: 24 April 2010.
5. ^ Jones 1975, p. 320.
6. ^ Jones 1975, p. 321.
7. ^ Winchester 2005, p. 104.

Bibliography

• Jones, Lloyd S. U.S. Fighters: Army-Air Force 1925 to 1980s. Fallbrook, California: Aero Publishers Inc., 1975. ISBN 0-8168-9200-0.
• Winchester, Jim. The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.

External links

• Video on Youtube
• Convair F2Y (F-7) Sea Dart