This high-flying, unmanned photo reconnaissance aircraft is an early example of stealth technology. Developed in the late 1960s to fly into deep China, Compass Arrow was to cruise at nearly 15 miles altitude while taking photos showing ground details as small as one foot in size. After air-launching from a DC-130E Hercules aircraft, Compass Arrow navigated automatically, but it also could be flown manually by an operator in the launch aircraft.
To present a small radar image and avoid surface-to-air missiles, Compass Arrow's vertical surfaces are canted inward, and its body uses radar-absorbing materials. The engine is mounted on top to reduce its heat signature from below, and the aircraft also carries anti-radar electronics.
Compass Arrow was ready to deploy by late 1971, but friendlier U.S. relations with China made it unnecessary. The AQM-91A never became operational. However, lessons learned from its development contributed to later stealth fighters, bombers and unmanned aerial vehicles.
Operational altitude: 78,000 ft. Endurance: 4.5 hours Range: 2,000 miles Photography: Coverage of an area 1,720 miles long and 43 miles wide Span: 48 ft. Length: 34 ft. Weight: 5,245 lbs.