Development of an Expendable, Gun-Launched Observation Vehicle

Development of an expendable observation vehicle is proposed which is capable of launch from guns with calibers from 120 to 155 mm, sustaining set-back loads of 15,000 g. A 10-pound payload of sensors and guidance and communications gear is to be carried in a loiter pattern at 10,000 feet altitude for 3 hours. A conceptual design for the vehicle was generated which meets the competing requirements for set-back load, launch weight and flight time while providing sufficient airspeed to sustain a prescribed search pattern through prevailing winds. The need for high L/D and high span loading is met by a wing with inflated spars supporting a fabric skin. The technology for this structure is proven and provides an efficient, affordable, gun-harden0d wing. Four folding fins stabilize the vehicle in ballistic flight and generate the roll torque commanded by a simple but effective flight controller. Propulsion is provided by a Wankel rotary engine fueled by propane and driving a pusher propeller, the rotary engine being well suited to gun hardening. The flight configuration has aspect-ratio 8 60-inch winds and 28.1 lb gross weight, for an airspeed at maximum endurance of 64 KTAS. Phase I objectives will be met by generating detailed designs for all OV elements and identifying those subsystems requiring risk-reduction testing in Phase II.