Cherry F3F

The Fatal Crash of the Prototype resulted from a mandatory crash dive test....at the bottom during the pull out the "g meter" found in the wreckage showed over 13 G's and the engine mount failed at the ripped of the "firewall". The resulting crash was witnessed by a couple of golfers...the aircraft was seen to shutter when this happened. The retractable wheels a first for a navy fighter, as well as a early "monocoque" fuselage. Grumman was trying several types of new technology advances in the F3 program...many seen in the F4F Wildcat. Better design a much higher horsepower engine, better monocoque design, all metal wing with carrier fold system.
Not to mention a monoplane. But the same basic gear retraction system. Also remember that the propeller technology in this aircraft was also a big step forward, a variable pitch prop and not the old Ham-Std Ground adjustable "fixed" pitch.