F2Y Sea Dart Testing
On 14 December 1952, E. D. "Sam" Shannon, Convair's Chief of Engineering Flight Test, took the XF2Y-1 Seadart out into San Diego Bay for its first taxi tests. The taxi tests revealed serious vibration and pounding that drastically increased with rougher water.
On 9 April 1953, Shannon made the first flight of the XF2Y-1. The dark blue paint with yellow markings provided aircraft attitude reference in instrumentation photos of taxi tests including take off and landing. Two afterburning Westinghouse J34 engines were soon replaced by Westinghouse's more powerful J46. The second Seadart exceeded Mach 1.0 on 3 August 1954.
At this point, the Navy began to rethink the program. The second prototype was cancelled, with development moving on to the first service evaluation YF2Y-1, fitted with J46 engines, although the Navy was seriously looking for a better powerplant.
The YF2Y-1 began test flights in 1954, and on 3 August 1954, Convair test pilot Charles E. Richbourg took the machine through Mach 1 in a shallow dive. The Sea Dart is believed to be the only seaplane to ever achieve Mach 1. However, as it had been designed before the new "area ruling" scheme was introduced, its supersonic handling characteristics were poor.
The YF2Y-1 was lost in a crash during a low-level demonstration on 4 November 1954, killing Richbourg. This accident essentially killed the program as well. The Navy was no longer particularly frightened of operating supersonic aircraft off of carriers, and despite improvements in the hydro-ski design, the Sea Dart still suffered from serious vibration on takeoff and landing.
The Navy had begun cutting back the program in December 1953, before the delivery of the YF2Y-1, cancelling ten of the production aircraft. The other six were killed off in March 1954, well before the fatal accident. Following the accident, the program was further scaled back to a test exercise, and plans to produce an "F2Y-2" with area ruling and a single Pratt & Whitney J75 turbojet with 66.71 kN (6,800 kgp / 15,000 lbf) thrust were abandoned.
The XF2Y-1 was then refitted with twin J46 turbojets and a single-ski configuration in hopes that would solve the takeoff and landing problems. The fit was strictly experimental. In mid-1954, the first Seadart was refitted with a single ski in an effort to reduce vibration during water operations. The ski was not fully retractable and the wells for the old twin skis were not faired over. The new single ski had a pair of retractable beaching wheels at the end, allowing the aircraft to beach itself. The modified XF2Y-1 first flew in late December 1954, and after some initial problems the single-ski scheme proved remarkably successful, allowing safe takeoffs and landings even in fairly rough seas.
The second YF2Y-1 performed its first flight in March 1955. It was powered by twin J46 turbojets and had a modified twin-ski system, with pivoting beaching wheels at the end of each ski. The final flight of the twin-ski version was made on 28 April 1955. The twin-ski system didn't work much better than before, and the aircraft was put into storage at the end of April 1955, never to fly again.
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