About This File
X-Plane 9 Republic XF-91 Thunderceptor. The XF91 was a research aircraft propelled with a jet engine and an array of four rockets. It was the first American fighter to become supersonic in horizontal flight. The Thunderceptor had many special features including a variable incidence wing, a wing chord that was shorter at the root than at the tip and a main landing gear made of tandem wheels that retracted outwards into the wing tip. By Jacques Brault.