The sole XC-99 in its early days of operation, before a nose radome was fitted.

The Convair XC-99 was a prototype heavy cargo aircraft built by Convair for the United States Air Force. It was the largest piston-engined land-based transport aircraft ever built, and was developed from the B-36 bomber, sharing the wings and some other structures with it. The first flight was on 23 November, 1947 in San Diego, California, and after testing it was delivered to the Air Force on November 23, 1949.

Design capacity of the XC-99 was 100,000 pounds of cargo or 400 fully equipped troops on its double cargo decks; a cargo lift was installed for easier loading.

The USAF determined that it had no need for such a large, long-range transport at that time, and no more were ordered. The sole XC-99 served until 1957, including much use during the Korean War.

The aircraft was put on display at Kelly Air Force Base near San Antonio, Texas. During the 1960s it was considered for restoration, but the deterioration of the airframe due to the high magnesium content led to the abandonment of that plan. The airplane was later on moved to a grassy field near the base. In 1993 the USAF re-acquired the plane and moved it back to the Kelly AFB tarmac. It is planned to move it via road to the US Air Force Museum at Wright-Patterson Air Force Base, restore and reassemble it, and put it on display in the USAF Museum's collection of experimental aircraft.

A civilian version of this aircraft was planned; this was the Convair Model 37. The plane was never built.

Specifications (XC-99)

General Characteristics

• Crew: 5
• Capacity: 45,000 kg (100,000 lb) or 400 troops
• Length: 56.4 m (185 ft)
• Wingspan: 70.10 m (230 ft)
• Height: 17.50 m (57 ft 5 in)
• Wing area: 443.3 m² (4,772 ft²)
• Maximum takeoff: 145,000 kg (320,000 lb)
• Powerplant: 6 × Pratt & Whitney Wasp Major, 2,600 kW (3,500 hp) each, 15,600 kW (21,000 hp) total

Performance

• Range: 13,000 km (8,000 miles)