It’s rare to find a twin-engine, piston-powered airplane with fixed-pitch propellers and nonretractable landing gear. In the post-World War II era, almost every piston twin utilized controllable-pitch propellers, both for efficiency and also so the pilot could feather a prop after an engine failure to reduce asymmetric drag and maintain control.
It’s also rare for an airplane to be optionally piloted—capable of flying both with a pilot aboard and also as an unmanned aerial vehicle. However, the Interstate TDR incorporated all these unique characteristics to fit a correspondingly unique set of mission requirements, specifically the ability to operate as a remotely piloted flying bomb. The “TD” portion of the designation signified “Torpedo Drone,” and the “R” was an arbitrary letter assigned to the Interstate Corporation.
