Langley Twin / 2-4 / Monoplane / XNL-1
The Langley 2-4, variously described as the Langley Monoplane or Langley Twin was a twin-engine utility aircraft built in the United States and first flown in 1940. Named in honour of Samuel Pierpont Langley, the aircraft was designed by Arthur Draper and Martin Jensen to make use of non-strategic materials in its construction and thereby avoid any shortages brought about by war. Its design was conventional - a low-wing cantilever monoplane with twin tails and tailwheel undercarriage.
The manufacturing process, however, was unorthodox, and the aircraft's structures were built up from mahogany veneers bent over moulds and impregnated with vinyl and phenol resins to make them hold their shape. The use of metal for structural elements - even in fasteners - was thereby almost completely avoided.
Two prototypes were constructed, one with 65 hp (49 kW) engines, and another with 90 hp (67 kW) engines. The second machine was purchased by the United States Navy and evaluated as the XNL-1, but the navy did not order the type. The Langley was a Type Certificated airplane, achieving ATC number 755.
Once the United States entered the war, it transpired that the resins needed for construction were in far shorter supply than the metal that would have been needed to produce an aircraft by conventional means, and the project was abandoned.
The XNL-1 was sold as war surplus. The Langley was landing in Oklahomain 1965 and after touch down the brakes locked flipping the airplane over and damaging the fuselage beyond economical repair.
John Pierce and Hurley Boehler had a Stinson 108 fuselage in their hangar without wings, so they decided to purchase the Langley and, following the accident, its wings, engine nacelles, and main undercarriage were mated to a Stinson 108 fuselage to create a one-of-a-kind homebuilt aircraft named the Pierce Arrow.
Engines: 2 × Franklin 4AC, 65 hp (49 kW)
Length: 20 ft 8 in (6.30 m)
Wingspan: 35 ft 2 in (10.72 m)
Maximum take-off weight: 1155 lb
Maximum speed: 135 mph (216 km/h)
Cruising speed: 185 kph
Range: 400 miles (640 km)
Service ceiling: 13,300 ft (4,100 m)
Crew: one pilot
Capacity: three passengers