__NOTOC__ The Boeing NB (or Model 21) was a primary training aircraft developed for the United States Navy in 1923. It was a two-bay, equal-span biplane of conventional configuration with interchangeable wheeled and float undercarriage. The pilot and instructor sat in tandem, open cockpits. The NBs were produced in two batches; the first (NB-1) were powered by radial engines and the second by war-surplus V-8s still in the Navy's inventory. The original prototype evaluated by the Navy had been assessed as being too easy to fly, and therefore of limited use as a trainer. In particular, it was noted that the aircraft was impossible to spin. The NB-1 design attempted to introduce some instability, but it was soon discovered that while it was now possible to get the aircraft into a spin, it was virtually impossible to recover from one. A series of modifications were made to attempt a compromise.

Variants

* VNB-1 - prototype (one built) * NB-1 - original production machine with

Lawrance J-1 The Lawrance J-1 was an engine developed by Charles Lanier Lawrance and used in American aircraft in the early 1920s. It was a nine-cylinder, air-cooled radial design. Development During World War I the Lawrance Aero Engine Company of New Yor ...

radial engine (41 built) Boeing NB-2 at Langley 1930

* NB-2 - production machine with

Wright-Hispano E The Hispano-Suiza 8 was a water-cooled V8 SOHC aero engine introduced by Hispano-Suiza in 1914, and was the most commonly used liquid-cooled engine in the aircraft of the Entente Powers during the First World War. The original Hispano-Suiza 8A ...

engine (30 built) * NB-3 - one NB-1 with lengthened fuselage and modified empennage to improve handling, and Hispano-Suiza E engine. Later refitted to standard NB-1 * NB-4 - one NB-1 converted similar to NB-3, but with Lawrance J-1 engine. Later refitted to standard NB-1

Operators

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United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

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Peruvian Naval Aviation The Peruvian Naval Aviation ( es, Fuerza de Aviación Naval) is the air branch of the Peruvian Navy. It was originally formed in 1919 as the Naval Aviators Corps (''Cuerpo de Aviadores Navales'') but was merged in 1932 with the Peruvian Army Aviat ...

(NB-1)

Specifications (NB-1)

References

* * {{USN trainer aircraft 1920s United States military trainer aircraft NB