North American BT-9

https://en.wikipedia.org/wiki/North_American_BT-9

The North American BT-9 was the United States Army Air Corps (USAAC) designation
for a low-wing single engine monoplane primary trainer aircraft that served
before and 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. The NJ-1, which was similar to the one off
BT-10, was used by the United States Navy.

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 flew in April 1936.

The wing and tail control surfaces were fabric-covered, 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-9s, BT-9As and BT-9Bs. Many
foreign countries also used variants of this aircraft under North American's
NA-16 designation.

The first BT-9C s/n 37-383 was built with a 600 hp Pratt & Whitney R-1340-41,
but was otherwise similar to the normal BT-9Cs. It was delivered as the Y1BT-10,
and later redesignated BT-10.

The BT-9D was a one off prototype that tested out a number of ideas that went
into production as the BT-14 (NA-58), which the similar North American NA-64
Yale 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-16s. The BT-14 featured a Pratt & Whitney R-985 engine versus the Wright
R-975 used on the BT-9. As well as metal skin replacing the fabric on the
fuselage, the fin was moved aft slightly, lengthening the rear fuselage while
the engine was moved forward to maintain the center of gravity. The rudder was
also changed from the rounded shape used previously to one with a roughly
triangular 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 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 the BT-14s longer fuselage and swept
forward outer wing panels, unlike the straight trailing edges of the BT-9 helped
somewhat.


Role
Trainer

Manufacturer
North American Aviation

First flight
April 1936

Primary users
United States Army Air Corps
United States Navy

Number built
+260

Unit cost

$20,000 USD


Developed from
North American NA-16

Developed into
North American BC-1

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.

Specifications (BT-9)

General characteristics
Crew: two, instructor and student
Length: 28 ft (8.5 m)
Wingspan: 42 ft (12.8 m)
Height: 13 ft 7 in (4.1 m)
Loaded weight: 4,470 lb (2,030 kg)
Powerplant: 1 × Wright R-975-53, 400 hp (300 kW)

Performance
Maximum speed: 170 mph (273 km/h)
Cruise speed: 146 mph (235 km/h)
Range: 877 mi (1,411 km)
Service ceiling: 19,750 ft (6,020 m)





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