XA-5 Top SergeantThe XA-5 Top Sergeant was a helicopter developed by American Helicopter in the late 1940s.DesignThe XA-5 had an open cockpit and the lower fuselage and undercarriage of a Sikorsky R-6 with an open rear boom and small rudder. The two rotor blades had two tip-mounted pulsejet engines driven by a fuselage-mounted compressor.DevelopmentThe XA-5 first flew in January 1949.