North American NA-16


The North American Aviation NA-16 was the first trainer aircraft built by North American Aviation, and was the beginning of a line of closely related North American trainer aircraft that would eventually number more than 17,000 examples.

Design and development

The NA-16 is a family of related single-engine, low-wing monoplanes with tandem seating.
Variants could have an open cockpit or be under a glass greenhouse that covered both cockpits. On some variants, the rear of the canopy could be opened for a gunner to fire to the rear. A variety of air-cooled radial engines, including the Wright Whirlwind, Pratt & Whitney Wasp and Pratt & Whitney Wasp Junior of varying horsepowers, could be installed depending on customer preferences. The fuselage was built up from steel tubes and normally fabric covered; however, later versions were provided with aluminium monocoque structures.
During the development of the design, a six-inch stretch was made by moving the rudder post aft. Many versions had a fixed landing gear, but later versions could have retractable gear, mounted in a widened wing center section. Most had a straight trailing edge on the outer wing while again, some had the wing trailing edge swept forward slightly in an attempt to fix a problem with stalls and spins. Several different rudders were used, with early examples having a round outline, intermediate examples having a square bottom on the rudder and late examples using the triangular rudder of the AT-6 series, due to a loss of control at high angles of attack with the early types. Horizontal and vertical tails were initially covered in corrugated aluminum, but later examples were smooth-skinned, and the horizontal stabilizer was increased in chord near its tips on later versions.
The NA-16 flew for the first time on 1 April 1935, and was submitted to the United States Army Air Corps for evaluation as a basic trainer. The Army accepted the trainer for production but with some detail changes. The modified NA-16 was redesignated by North American as the NA-18, with production examples entering Air Corps service as the North American BT-9. Similar aircraft continued to be sold outside the U.S. under the NA-16 designation.

Foreign developments

;Australia
The Commonwealth Aircraft Corporation produced 755 units of a modified version of the NA-16-2K known there as the Wirraway between 1939 and 1946.
;Argentina
Experience with the NA-16-4P and deteriorating political relations with the US led to the local development of the I.Ae. D.L. 21, which shared the NA-16 fuselage structure; however it proved too difficult to produce. As a result of this, an entirely new design was built instead; it had similar configuration, but was structurally different and optimized to available materials.
;Japan
The NA-16-4RW and NA-16-4R inspired the development of the Kyushu K10W when the Imperial Japanese Navy instructed Kyushu to develop something similar. The resulting aircraft owed little to the NA-16, however Allied Intelligence saw so few examples that the error was not corrected and some drawings show a modified NA-16.

Variants

Listing includes aircraft built specifically under NA-16 designation for export, and similar aircraft built for use by the United States armed forces.
;NA-16
When the North American NA-16 was first conceived, five different roles were intended for the design, designated NA-16-1 thru NA-16-5:
;NA-16-1:General purpose two-seat aircraft - which became the Harvard I
;NA-16-2:Two-seat fighter - produced under licence in Australia as the CAC Wirraway.
;NA-16-3:Two-seat light attack bomber. The first aircraft in this category was the retractable gear NA-26 which evolved into the NA-36. The fabric-covered fuselage was replaced by an all-metal monocoque to create the NA-44, which provided the basis for a line of light attack bombers whose improvements would result in the AT-6.
;NA-16-4:Advanced trainer - became the BT-9 for the USAAC and which provided the bulk of early production. The improvement of the BT-9 with a longer metal skinned fuselage as on the NA-44 would create the NA-64 and improved wings would result in the BT-14.
;NA-16-5:Single-seat fighter - although this designation was never used, it became the NA-50 for Peru, and later the NA-68, which saw limited USAAF service as the P-64.
;BT-9
;BT-9A
;NA-16-2H
;NA-22
;BT-9B
;BT-9D
;NA-16-3 Basic Combat demonstrator
;NA-16-2H
;NJ-1
;BT-9C
;Y1BT-10
;BT-10
;NA-16-4M
;NA-16-1A
;NA-16-2K
;NA-16-4P
;NA-16-4R
;NA-16-4
;NA-16-2A
;NA-16-1G
;NA-44
;NA-16-1GV
;NA-16-4
;NA-16-4RW
;NA-16-3C
;NA-16-1E
;NA-16-4
;NA-57
;NA-16-3
;I.Ae. D.L. 21

Operators

Citations