Convair F2Y Sea Dart

Convair F2Y Sea Dart supersonic seaplane

The Convair F2Y Sea Dart was a fascinating experimental aircraft which was built to fulfil a 1948  US Navy request for a supersonic jet seaplane. The F2Y Sea Dart featured a delta-wing layout, watertight hull and two retractable hydro-skis which were deployed for takeoff and landing. When the aircraft was stationary, or moving at under 10 mph in the water, the skis were retracted. This meant the Sea Dart sat so low in the water that the trailing edge of the wings actually touched the surface of the water.

The US Navy were impressed with the initial results of the F2Y Sea Dart project, and after the two prototypes were ordered in 1951, a further twelve production aircraft were ordered even before the first flight had been made. No Sea Dart was ever fitted with armaments, but the plan was to fit the aircraft with four 20mm cannons, and number of unguided rockets.

There was also an interesting Navy proposal which suggested that some submarines could be built which carried a trio of Sea Darts within their hull. The aircraft would be raised by a port side elevator just behind the conning tower. They could then takeoff on their own on smooth seas, or be fired from a catapult in rougher seas. This idea didn’t get very far though, as there were a number of  engineering problems with the submarine/elevator/catapult combination which would have been extremely difficult and costly to resolve.

The original idea was to fit the Convair F2Y Sea Dart with two afterburning Westinghouse XJ46-WE-02 turbojets. But unfortunately these were not ready for the prototype. So instead the aircraft was equipped with a pair of Westinghouse J34-WE-32 engines – which produced just over half the thrust of the XJ46-WE-02 turbojets.

Due to the underpowered engines the original prototype Convair F2Y Sea Dart wasn’t as fast as originally hoped, and with the J34-WE-32 engines supersonic flight was impossible. However when the second aircraft was fitted with the more powerful XJ46-WE-02 turbojets, the Sea Dart did achieve supersonic flight. But even then the performance wasn’t as good as the engineers expected, and exceeding Mach 1 was only possible if the aircraft was put into a shallow dive. Still, it put the F2Y Sea Dart into the record books as the first, and to this date only, supersonic seaplane.

Aside from the lackluster performance, there were a number of other issues with the F2Y Sea Dart. The most prominent of these was the violent vibrations the aircraft suffered during takeoff and landings. Subsequent revisions of the hydro-skis helped reduce the shaking. But there was no cure for the lack of overall performance.

Sadly, on November 4th 1954, when Sea Dart, No 135762, was being shown off to Navy officials and the press, it disintegrated in mid-air over San Diego Bay, killing Convair test pilot Charles E. Richbourg.

Even before this tragic incident, the US Navy had started to lose interest in the Convair Sea Dart. Especially as they were now concentrating on equipping their aircraft carriers with the first-generation of supersonic fighters – eliminating the need for supersonic seaplanes.  Any unbuilt Sea Darts were cancelled shortly after the crash, and the Sea Dart program was relegated to experimental status.

The last flight of the Convair Sea Dart was in 1957. All four remaining Sea Darts survive to this day.
– XF2Y-1 Sea Dart, No. 137634, is in bad shape and is awaiting restoration for the Smithsonian Institution in Washington D.C.
– YF2Y-1 Sea Dart, No. 135763, is on display at the San Diego Aerospace Museum.
– YF2Y-1 Sea Dart, No. 135764, never flew and is on display at the Wings of Freedom Aviation Museum in Pennsylvania.
– YF2Y-1 Sea Dart, Bureau Number 135765, never flew and is on display at the Florida Air Museum.

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