North American NA-64 Yale
Single-engine two-seat low-wing monoplane advanced trainer

Archive Photos

North American NA-64 Yale (C-FCWZ, c/n 64-2206) on display (9/22/2003) at the Canadian Warplane Heritage Museum, Mount Hope, Ontario, Canada (Photos by John Shupek)

North American NA-64 Yale (NA-64, c/n 64-2183, N3361) on display (4/20/2005) at the Milestones of Flight Air Museum, Fox Field, Lancaster, CA (Photos by John Shupek)

Overview

The North American Aviation BT-9 was a low-wing single piston engine monoplane primary trainer aircraft that served with the United States Army Air Corps (USAAC) and other allied countries during World War II. It was a contemporary of the Kaydet biplane trainer and was used by pilots in Basic Flying Training following their completion of Primary in the Kaydet. In United States Navy (USN) service it was designated the NJ-1.

Design and Development

The BT-9, designated NA-19 by the manufacturer, evolved from the North American NA-16, which first flew in April 1935. The BT-9 design first took to the skies in April 1936.

Fabric covered the movable surfaces on the tail and wings, as well as the sides of the fuselage from just behind the firewall to the tail. The remainder of the aircraft was metal-covered and featured fixed (non-retractable) landing gear. The Army Air Corps purchased a total of 199 BT-9’s, BT-9A’s and BT-9B’s. Many foreign countries also used variants of this aircraft under North American’s NA-16 designation.

The BT-14 (NA-58) and the similar NA-64 Yale I represented a major aerodynamic improvement over the NA-16 series, with a longer all metal fuselage replacing the fabric covered fuselage of the earlier NA-16’s. The BT-14 featured a Pratt & Whitney R-985 engine versus the Wright R-975 used on the BT-9 and NA-64. As well as metal skin replacing the fabric on the fuselage, the fin was changed from having a corrugated surface on the BT-9’s to being a smooth stressed skin structure and was moved aft slightly, lengthening the rear fuselage while the engine was moved forward to maintain the CG. The rudder was also changed from the rounded shape used previously to one with a roughly triangle shape with the broadest part being at the bottom, and the canopy was redesigned. The new fuselage would provide the basis for the entire AT-6 family, when fitted with the larger Pratt & Whitney R-1340 engine, a new wing with retractable undercarriage and minor changes for a gunners position.

The BT-9 and NA-64 suffered from stall/spin problems and a variety of fixes were tried. The USAAC temporarily settled on using slats on the later versions of the BT-9 however these did not work well, and later developments would have the outer wing panels swept forward slightly so that they no longer had the straight trailing edges of the BT-9 and NA-64. The later swept forward wings were fitted to the BT-14.

Operational History

The NA-64 retained the fixed undercarriage layout and was built for the French Armée de l’Air and Aéronavale in 19391940. Just under half were delivered before France surrendered to the Nazis and the remaining aircraft were purchased by the British Purchasing Commission for the Royal Canadian Air Force (RCAF). The RCAF named the type the Yale, and were used initially as intermediate pilot trainers and later as airborne wireless radio trainers. All were sold as scrap post-war but approximately 40 survive today, with about 15 in airworthy condition.

The NA-26, an improved model with retractable landing gear which became the prototype for AT-6 Texan advanced trainer, was developed from the NA-16 design. The Australian CAC Wirraway was also developed from the NA-16.

Variants

Operators

North American NA-64 Yale I Specifications and Performance Data

Type

Wings

Fuselage

Tail Unit

Undercarriage

Power Plant

Accommodation

Dimensions

Weights

Armament

Performance

References

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