High Quality Content by WIKIPEDIA articles! The Grumman XF5F Skyrocket was a prototype of a twin-engine shipboard fighter interceptor to which Grumman Aircraft Engineering Corporation applied the model number G-34. The U.S. Navy ordered one prototype airplane on 30 June 1938 with the designation XF5F-1. The aircraft possessed a unique appearance in that the forward part of the fuselage did not extend forward of the wing. Provisions were included in the prototype for two 23 mm (0.91 in) Madsen cannon.