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The Boeing Model 81 was an American training aircraft built by Boeing in 1928. The Model 81 was a development of the Model 64. It was powered by a newly developed engine, the 125 hp Fairchild-Caminez 4-cylinder radial engine. Operating at a much lower rpm than most engines (1000 rpm) it required the use of a large high-pitch propeller.
After initial flight tests with the Fairchild-Caminez, the prototype was refitted with a 145 hp
The Boeing Model 81 was an American training aircraft built by Boeing in 1928. The Model 81 was a development of the Model 64. It was powered by a newly developed engine, the 125 hp Fairchild-Caminez 4-cylinder radial engine. Operating at a much lower rpm than most engines (1000 rpm) it required the use of a large high-pitch propeller.
After initial flight tests with the Fairchild-Caminez, the prototype was refitted with a 145 hp Axelson Axelson is a surname. Notable people with the surname include:
*Jan Axelson (born 1949), American author and conservationist
*Joe Axelson (1927–2008), American sports executive
*Matthew Axelson (1976–2005), American Navy SEAL
See also
*Axelso ...
engine, redesignated ''Model 81A'' and delivered to the Boeing School of Aeronautics. There, it was re-engined a number of times, first with a 115 hp Axelson engine, redesignated ''Model 81B''. It then received a 165 hp Wright J-6-5
The Wright R-540 Whirlwind was a series of five-cylinder air-cooled radial aircraft engines built by the Wright Aeronautical division of Curtiss-Wright. These engines had a displacement of 540 in³ (8.85 L) and power ratings of around ...
, then a 100 hp Kinner K-5 and a redesigned vertical tail. Redesignated ''Model 81C'', it would later be removed from training service, re-engined with an Axelson engine, and used as a classroom trainer.
On 21 June 1928, the second Model 81 built was delivered to the US Navy at Anacostia, Maryland for $8,300, and redesignated ''Boeing XN2B''. Its trial with the Fairchild engine was unsatisfactory, and on 10 January 1929 it was refitted by Wright Aeronautical with a 160 hp Wright J-6-5 engine. Despite increased performance, it was not ordered into production.Bowers, 1989, pp. 142-144
Variants
;81 :Original Caminez-engined aircraft ;81A :145 hp Axelson engine ;81B :115 hp Axelson engine ;81C :100 hp Kinner K-5, redesigned tail. ;XN2B :US Navy designation.Operators
; *Boeing School of AeronauticsSpecifications (XN2B)
References
*Bowers, Peter M. ''Boeing aircraft since 1916''. London: Putnam Aeronautical Books, 1989. {{Boeing model numbers Boeing Model 081 081 Single-engined tractor aircraft Biplanes Aircraft first flown in 1928