Ever hear of the Convair F2Y Sea Dart? It’s the world’s first supersonic seaplane, born of the early Cold War when many innovations in aviation were attempted.
Why attempt the Sea Dart?
The Sea Dart was an attempt at a seaplane fighter jet that would not have the challenges early jets had operating from aircraft carriers due to high approach speeds and long take-off rolls. Plus, not having a large runway would reduce the risk of the operating base being targeted.
So Convair proposed a delta-winged fighter with extending water skis to launch off of the water. The skis would extend only during the take-off roll and shortly before landing to make an airborne shape able of handling the water environment. However, there were wheels on the skis so the Sea Dart could wheel itself into and out of the water. Also there were some Sea Darts with two skis, and some with one.
Making a fighter jet seaborne
According to the San Diego Air and Space Museum about the watertight design of the Sea Dart;
“The hull of the Sea Dart had multiple watertight compartments in the lower fuselage to prevent sinking in the event of a puncture. It was fitted with a set of dive brakes on the lower rear fuselage which also doubled as water brakes and as a water rudder while taxiing on the surface. When sitting at rest in the water, the Sea Dart floated with the trailing edge of the wing and the twin hydro-skis flush with the water, and the leading edge of the delta wing at the juncture of the fuselage about 18 inches above the water.”
Although the design was clearly thoughtfully engineered, the execution of the design would face multiple challenges. For one, the intended powerplant of two afterburning Westinghouse XJ46-WE-02 turbojets was unavailable for the prototypes, so twin Westinghouse J34-WE-32 engines were substituted. This would contribute to the short life of the Sea Dart.
Flight tests expose fundamental problems
Flight testing of the Sea Dart would start on January 14, 1953, when E. D. “Sam” Shannon accidentally, during a taxi test, let the Sea Dart fly. The formal first flight was on April 9, 1953.
Initial flight tests found the prototype Sea Darts woefully underpowered. Granted, again, the initial engines were about half the power of the production engines, but still.
The skis would also be insufficient to deal with the stresses of high-speed water takeoff as there were violent vibrations. The aircraft did not handle rough seas well either, to the point that plans to recover the Sea Dart on the open seas were scuttled.
Another problem was that even with the intakes on the top of the fuselage, saltwater would still get into the engines. So a freshwater injection system had to be installed.
Furthermore, the aircraft fuselage needed to be modified from its initial shape to an area-rule body, so the Sea Dart could go supersonic. The costs were high and intimidating to the US Naval Aviation Enterprise.
Flight test crash
By November 1954, the Convair Sea Dart was still in flight testing. Expensive modifications were made to the aircraft, with more projected to come.
Then, as if the Sea Dart needed more problems, November 4, 1954, would roll around. A prototype Sea Dart was being put through aerial demonstrations, and Convair test pilot Charles E. Richbourg sadly had the aircraft disintegrate on him. Although rescued, Richbourg did not recover from his injuries.
The Convair Sea Dart was an experiment in jet seaplanes. The experiment failed for multiple reasons – not the least of which the jet needed modifications that added weight, the high speeds stressed the airframe structure, and the need for more speed required an expensive fuselage modification.
Although the recent movie Devotion shows the propeller Corsairs – among other naval aviation warbirds – in Korean War action, more and more jets were coming. US Naval Aviation was evolving from straight-deck carriers, with most having no catapults, to a mostly-jet force launching from carriers with steam catapults.
As such, the Convair Sea Dart was shelved and stored in 1957. No future attempts have resulted in a supersonic seaplane.
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Source: San Diego Air & Space Museum