| 词条 | Boeing Model 81 | ||||||||||
| 释义 |
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.[1] Operating at a much lower rpm than most engines (1000 rpm) it required the use of a large high-pitch propeller.[2] After initial flight tests with the Fairchild-Caminez, the prototype was refitted with a 145 hp Axelson 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, 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.[3] 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.[4] Variants
Original Caminez-engined aircraft
145 hp Axelson engine
115 hp Axelson engine
100 hp Kinner K-5, redesigned tail.
US Navy designation. Operators
Specifications (XN2B){{aerospecs|ref=Bowers, 1989. p. 144 |met or eng?=eng |crew=2 |length m=7.82 |length ft=25 |length in=8 |span m=10.67 |span ft=35 |span in= |height m=3.40 |height ft=11 |height in=2 |wing area sqm=24.06 |wing area sqft=259 |empty weight kg=750 |empty weight lb=1,652 |gross weight kg=988 |gross weight lb=2,178 |eng1 number=1 |eng1 type=Fairchild-Caminez |eng1 kw=93 |eng1 hp=125 |max speed kmh=167 |max speed mph=103.9 |cruise speed kmh=138 |cruise speed mph=86 |stall speed kmh= |stall speed mph= |range km=539 |range miles=335 |endurance h= |endurance min= |ceiling m=3660 |ceiling ft=12,000 |climb rate ms=2.62 |climb rate ftmin=515 }} References{{commons category|Boeing Model 81}}1. ^A diagram of the 4-cylinder Fairchild-Caminez cam engine 2. ^Bowers, 1989, p. 142 3. ^Bowers, 1989, pp. 144-145 4. ^Bowers, 1989, pp. 142-144
5 : United States military trainer aircraft 1920–1929|Boeing aircraft|Single-engined tractor aircraft|Biplanes|Aircraft first flown in 1928 |
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