Goodyear XAO-2 / XAO-3 Inflatobird
The original concept of an all-fabric inflatable aircraft was based on Taylor McDaniel inflatable rubber glider experiments in 1931. Designed and built in only 12 weeks, the Goodyear Inflatoplane was built in 1956, with the idea that it could be used by the military as a rescue plane to be dropped in a hardened container behind enemy lines. The 44 cubic ft (1.25 cubic meter) container could also be transported by truck, jeep trailer or aircraft.
The inflatable surface of this aircraft was actually a sandwich of two rubber-type materials connected by a mesh of nylon threads, forming an I-beam. When the nylon was exposed to air, it absorbed and repelled water as it stiffened, giving the aircraft its shape and rigidity. Structural integrity was retained in flight with forced air being continually circulated by the aircraft's motor and guy wires.
There were at least two versions: The GA-468 was a single-seater. It took about five minutes to inflate to about 25 psi (170 kPa); at full size, it was 19 ft 7 in (5.97 m) long, with a 22 ft (6.7 m) wingspan. A pilot would then hand-start the two-stroke cycle, 40 horsepower (30 kW) Nelson engine, and takeoff with a maximum load of 240 pounds (110 kg). On 20 US gallons (76 L) of fuel, the aircraft could fly 390 miles (630 km), with an endurance of 6.5 hours. Maximum speed was 72 miles per hour (116 km/h), with a cruise speed of 60 mph. Later, a 42 horsepower (31 kW) engine was used in the aircraft.
Takeoff from turf was in 250 feet with 575 feet needed to clear a 50 foot obstacle. It landed in 350 feet. Rate of climb was 550 feet per minute. Its service ceiling was estimated at 10,000 ft.
The GA-466 was the two-seater version, 2 in (51 mm) shorter, but with a 6 ft (1.8 m) longer wingspan than the GA-468. A more powerful 60 horsepower (45 kW) McCulloch 4318 engine could power the 740 pounds (340 kg) of plane and passenger to 70 miles per hour (110 km/h), although the range of the plane was limited to 275 miles (443 km).
The test program at Goodyear's facilities near Wingfoot Lake, Akron, Ohio showed that the inflation could be accomplished with as little as 8 psi (544 mbar), less than a car tire. The flight test program had a fatal crash when Army aviator Lt. "Pug" Wallace was killed. The aircraft was in a descending turn when one of the control cables under the wing came off the pulley and was wedged in the pulley bracket, locking the stick. The turn tightened until one of the wings folded up over the prop and was chopped up. With the wings flapping because of loss of air, one of the aluminum wing tip skids hit the pilot alongside the head, as was clear from marks on his helmet. Wallace was pitched out over the nose of the aircraft and fell into the shallow lake. His chute never opened. He may have been knocked unconscious and rendered unable to open it.
Only 12 Goodyear Inflatoplanes were built, but development continued until the project was cancelled in 1973. The US Army was not ready for blow-up aircraft, however, and civilian certification standards prevented Goodyear from offer-ing their Inflatobird to the public.
Goodyear donated two Inflatoplanes for museum display at the end of the project, one to the Franklin Institute in Philadelphia and one to the Smithsonian Institution in Washington, D.C.