North American NA-16

The North American Aviation NA-16 was the first trainer aircraft built by North American Aviation, Inc. 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 was a family of related single-engine, low-wing monoplanes with tandem seating.

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 2 seat aircraft - which became the Harvard I
 * NA-16-2 2 seat fighter - produced under licence in Australia as the CAC Wirraway.
 * NA-16-3 2 seat light attack bomber. The first aircraft in this category was the retractable undercarriage NA-26 which evolved into the NA-36 (BC-1). The fabric covered fuselage was replaced by an all metal monococque 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 (Yale) 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 Chile, and later the NA-68, which saw limited USAAF service as the P-64.

Variants could have an open cockpit (the prototype and the NA-22) 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 monococoque structures.

During the development of the design, a 6 inch stretch was made by moving the rudder post aft. Many versions had a fixed landing gear, but later versions could have a retractable undercarriage, mounted in a widened wing center section (which could have either integral fuel tanks or not. 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 (Harvard I) 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 re-designated by North American as the NA-18, with production examples entering Air Corps service as the North American BT-9 (NA-19). Similar aircraft continued to be sold outside the U.S. under the NA-16 designation.

In 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.

Argentine 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 and an entirely new design (the I.Ae. D.L. 22) of similar configuration, but structurally different and optimized to available materials was built instead.

In 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
 * 1 for United States Army Air Corps (USAAC) (trials) developed into NA-18 and BT-9 series.
 * powered by Wright R-975 Whirlwind


 * BT-9 (NA-19)
 * 42 built for USAAC 	- Minor changes from NA-18, new canopy
 * powered by Wright R-975 Whirlwind


 * BT-9A (NA-19A)
 * 40 built for USAAC 	- Armed BT-9 with one cowl gun, one rear flexible gun and modified canopy.
 * powered by Wright R-975 Whirlwind


 * NA-16-2H (NA-20)
 * 1 built for trials, sold to Honduras (FAH)
 * powered by Wright R-975 Whirlwind


 * NA-22
 * 1 built for USAAC trials but rejected as severely underpowered. Open cockpits as per early NA-16 and Townend ring on engine.
 * powered by Wright R-760 Whirlwind


 * BT-9B (NA-23)
 * 117 built for USAAC - Unarmed with fixed rear on canopy.
 * powered by Wright R-975 Whirlwind


 * BT-9D (NA-23)
 * 1 modified BT-9B for USAAC - BT-14 prototype with new outer wings, Harvard type canopy, lengthened fabric covered fuselage, triangular rudder and detail alterations.
 * powered by Pratt & Whitney R-985 Wasp Junior


 * NA-16-3 Basic Combat demonstrator (NA-26)
 * 1 armed demonstrator and the first variant with retractable undercarriage, eventually sold to RCAF who modified it with Yale and Harvard parts.
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-2H (NA-27)
 * 1 armed demonstrator sold to Royal Netherlands Air Force - not the same as the previous NA-16-2H.
 * powered by Pratt & Whitney R-1340 Wasp


 * NJ-1 (NA-28)
 * 40 built to US Navy specifications, up engined BT-9B as advanced trainer with fixed undercarriage.
 * powered by Pratt & Whitney R-1340 Wasp


 * BT-9C (NA-29)
 * 66 built for USAAC - BT-9A with minor changes.
 * powered by Wright R-975 Whirlwind


 * Y1BT-10 (NA-29)
 * 1 built for USAAC - BT-9 with larger engine, similar to USN NJ-1 but armed and detail differences in engine installation.
 * powered by Pratt & Whitney R-1340 Wasp


 * BT-10 (NA-30)
 * Cancelled production version of Y1BT-10 for USAAC
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-4M (NA-31)
 * 138 built for Sweden's Flygvapnet as Sk-14/Sk-14A. Sk-14N trialled nosewheel for SAAB 21.
 * powered by Wright R-975 Whirlwind (Sk-14) or Piaggio P VIIc (Sk-14A)


 * NA-16-1A (NA-32)
 * 1 built for Royal Australian Air Force but rejected in favour of NA-16-2K, fixed landing gear, similar to Y1BT-10.
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-2K (NA-33)
 * 756 for Royal Australian Air Force in Australia with local improvements as CAC Wirraway
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-4P (NA-34)
 * 29 built for Argentina (FAA) - 1st major export order (previous orders involved licence production).
 * powered by Wright R-975 Whirlwind


 * NA-16-4R (NA-37)
 * 1 built for Imperial Japanese Navy as a technology demonstrator KXA-1 with fixed u/c and 3 blade prop.
 * powered by Pratt & Whitney R-985 Wasp Junior


 * NA-16-4 (NA-41)
 * 35 built for China (RoCAF) - Fixed gear, fabric covered fuselage
 * powered by Wright R-975 Whirlwind


 * NA-16-2A (NA-42)
 * 2 built for Honduras (FAH)
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-1G (NA-43)
 * intended for Brazil (Army) but order cancelled. Was to have been similar to BT-9C
 * powered by Wright R-975 Whirlwind


 * NA-16-1GV (NA-45)
 * 3 built for Venezuela (FAV) similar to USAAC NA-36 BC-1 but with round rudder and bomb racks under wing center section.
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-4 (NA-46)
 * 12 built for Brazilian Navy
 * powered by Wright R-975 Whirlwind


 * NA-16-4RW (NA-47)
 * 1 built for Imperial Japanese Navy as a technology demonstrator KXA-2 similar to NA-16-4R but smaller engine.
 * powered by Wright R-975 Whirlwind


 * NA-16-3C (NA-48)
 * 15 built for China (RoCAF) - Retractable undercarriage, fabric covered fuselage
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-1E (NA-49/NA-61)
 * 430 for Royal Air Force and Royal Canadian Air Force as the Harvard I with new canopy and square rudder. Also used by South Africa and Southern Rhodesia.
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-16-4 (NA-56)
 * 50 built for China (RoCAF) - Entirely new design with longer metal fuselage, triangular rudder and later T-6 style wing. Basically a BT-14 with the AT-6s R-1340 engine and canopy.
 * powered by Pratt & Whitney R-1340 Wasp


 * NA-57
 * 230 improved NA-23s for France as NAA 57-P-2, most captured and used by Germany, some retained by Vichy France.
 * powered by Wright R-975 Whirlwind


 * NA-16-3 (NA-71)
 * 3 built for Venezuela (FAV)
 * powered by Pratt & Whitney R-1340 Wasp

Operators

 * Argentine Air Force (Fuerza Aérea Argentina/FAA)
 * Royal Australian Air Force (RAAF) (samples for licence production)
 * Brazilian Navy (Marinha do Brasil)
 * 🇨🇦 Canada
 * Royal Canadian Air Force (RCAF)
 * Republic of China Air Force (RoCAF)
 * French Air Force (Armée de l'Air)
 * French Naval Aviation (Aéronavale)
 * Vichy French Air Force
 * 🇩🇪 Germany
 * Luftwaffe
 * Honduran Air Force (Fuerza Aérea Hondureña/FAH)
 * 🇯🇵 Japan
 * Imperial Japanese Navy Air Service(IJNAS) (for evaluation only)
 * Royal Netherlands Air Force (Koninklijke Luchtmacht/KLu)
 * 🇿🇦 South Africa
 * South African Air Force (SAAF)
 * Southern Rhodesia
 * Southern Rhodesian Air Force (SRAF)
 * Swedish Air Force (Flygvapnet)
 * Royal Air Force (RAF)
 * 🇺🇸 United States
 * United States Army Air Corps (USAAC)/United States Army Air Forces (USAAF)
 * United States Navy (USN)
 * Venezuelan Air Force (Fuerza Aérea Venezolana/FAV)
 * Southern Rhodesian Air Force (SRAF)
 * Swedish Air Force (Flygvapnet)
 * Royal Air Force (RAF)
 * 🇺🇸 United States
 * United States Army Air Corps (USAAC)/United States Army Air Forces (USAAF)
 * United States Navy (USN)
 * Venezuelan Air Force (Fuerza Aérea Venezolana/FAV)
 * United States Navy (USN)
 * Venezuelan Air Force (Fuerza Aérea Venezolana/FAV)
 * Venezuelan Air Force (Fuerza Aérea Venezolana/FAV)

Surviving aircraft

 * The only intact surviving example of an American built NA-16 is the NA-16-2A/NA-20 "FAH-21" displayed at the Honduras Air Museum at Toncontín.
 * A Swedish NA-16-4M (locally designated as Sk-14) was built from an ex-RAAF CAC Wirraway (s/n A20-223) with additional parts from an ex-RCAF North American NA-64 Yale and is on display at the Swedish Air Force Museum.
 * The CAC Wirraway (originally NA-16-2K) was first modified to British standards and equipment, then later models diverged further from the NA-16 in minor details. A total of 10 are on the Australian civil aircraft register. Further examples (in Australia unless noted) are at Temora Aviation Museum, Australian National Aviation Museum, Aviation Heritage Museum, Fleet Air Arm Museum (Australia), RAAF Museum (Stored) and the Fantasy of Flight (Florida - stored).