The streamlined model 2-4-65 (initially designated simply Langley Monoplane) was designed by Martin Jensen, assisted by Arthur Draper. The pictured first prototype was powered by two 65 hp Franklin engines. To emphasize its wood construction it was finished in clear varnish, hence it was also called "an exquisite piece of furniture". Registered NX29099, it was first flown in 1941.
As the aircraft was underpowered the second Langley Monoplane prototype was initially fitted with two 75 hp engines which soon were replaced by two 90 hp engines. This prototype was designated 2-4-90 and was first flown in 1942. Subsequently it was purchased by the USN under the designation XNL-1 and BuNo. 39056. The Langley Aircraft Corporation received the CAA Type Certificate Number 755 for the model 2-4-90 on December 29, 1943. In the previous year Langley had been acquired by the Andover-Kent Aviation Company at New Brunswick, New Jersey and the latter company planned to produce the type in series. Ironically, by the time of certification the plastic compositions were no longer available as they became strategic materials and the project was ended. Reports that examples were produced after WW II are not supported by known allotted registrations.
The XNL-1 was sold as war surplus and it came on the civil registry as NC51076, on January 1, 1949, the "C" was dropped from the registration. On September 26, 1965, the aircraft ground-looped upon landing at Tulsa, Oklahoma, USA and the fuselage was damaged beyond economical repair. Subsequently the undamaged wings and engines were used to build the Pierce Arrow.
The following data is from 1942.
TYPE. Four-seat cabin monoplane.
WINGS. Low-wing cantilever monoplane in five sections, comprising rectangular center-section, two tapering outer and two semi-circular wing-tips. Ailerons on outer tapering sections.
FUSELAGE. Molded plastic plywood structure in three sections, comprising a nose-piece and two longitudinal halves joined down the vertical center-line.
TAIL UNIT. Braced monoplane type with twin fins and rudders of molded plastic plywood construction. Single-piece elevator.
UNDERCARRIAGE. Fixed type. Consists of two cantilever shock-absorber legs with medium-pressure wheels carried in forks. Orientable tail-wheel.
POWER PLANT. Two 65 hp Franklin 4AC-176 (in 2-4-90 two 90 hp 4AC-199-E3) four-cylinder horizontally-opposed air-cooled engines in molded plastic plywood nacelles. Engine cowlings and fireproof bulkheads molded with an integral asbestos lining. Fuel tanks (40 gall, 151 l total capacity) in tails of engine nacelles behind fireproof bulkheads.
ACCOMMODATION. Enclosed cabin seating four in two pairs, the front pair having dual controls.