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North American NA-26 / BC-1 / T-6 / SNJ / Harvard / A-27

naa-harvard2
Harvard Mk.II


Derived from the 1935 NA-16 prototype, the North American NA-26 design was first flown in 1938.  This aircraft was designated the Basic Combat Trainer, BC-1. The BC-1 (basic combat, type 1) had the same basic airframe design as the BT-9 but with a retractable main landing gear and more power. It was equipped with one nose-mounted .30-caliber machine gun that fired through the propeller and a second .30-caliber gun on a flexible mount in the rear cockpit.

The first one flew on February 11, 1938. The Edward G. Budd Manufacturing Co. was subcontracted to experiment with stainless steel in the wing panels to determine its structural feasibility in the aircraft. It had seven inches more wing- span, larger tanks and a higher gross weight (by approx 155 pounds) when compared to the later T-6.

In 1939, the U.S. Army Air Corps ordered an additional 200 of the advanced BC-1A type, and the U.S. Navy a number of the same type but designated as SNJ-1.

The Navy had been searching for a trainer for pilots destined to fly its scout aircraft, such as the Douglas SBD dive bomber, and it chose the BC-1. The BC-1 was ordered in 1937 to the extent of 41 aircraft with the R-1340-45 radial. Blunt wing tips and a straight-edged rudder characterised the BC-lA, of which 92 were ordered and the last six delivered as AT-6s after a change in designation policy during 1940. AT-6 orders covered an extra 85 aircraft, and production then switched to 1,429 AT-6As with the R-1340-49 engine and modified fuel tankage. The full production flood now saw 400 AT-6B gunnery trainers with the R-1340-AN-1, 2,970 AT-6Cs with a high proportion of non-strategic materials, 3,713 AT-6Ds with the original structure and 24-volt electrics, and 25 AT-6Fs with a strengthened airframe. US Navy variants equivalent to the BC-1, AT-6, AT-6A, AT-6C, AT-6D and AT-6F were the SNJ-1 to -6 respectively, of which 4,765 were delivered.

A total of 2,068 wartime aircraft were remanufactured as T-6G.

North American engineers designed two variants of the BC-1 to sell to overseas buyers as fighters and attack planes. One was a single-seat fighter and the other a two-seater; both had five .30-caliber ma­chine guns in the wings and nose. The attack version (NA-44, -69, -72)also had a flexible ma­chine gun in the rear cockpit. The first order, from the Siamese air force, was for 10 A-27 (NA-69), including both versions.
 
NA-A27-01
North American A-27
 
Brazil, Peru and Chile ordered 49 single-seat fighters. Brazil received 30 NA-72 with P&W R-1340 in 1940 and one armed prototype NA-44 went to the RCAF in 1940.
 
Siam never received any of the aircraft, however. Tension was increasing at the time between Siam and French Indochina, and the State Department prohibited the transfer. The aircraft were diverted to the Philippines, where they were taken over by the U.S. Army Air Corps, re-designated A-27 (41-18890/18899), where they were destroyed in Japanese bombings during Dec 1941. Several A-27s saw action in the Philippines on December 8, 1941, against invading Japanese forces. The single-seat version was stripped of arma­ment, returned to the States for fighter-pilot training and designated the P-64.

 

The Navy later requested several modifications to the SNJ-1, including a more powerful engine. That changed the designation to SNJ-2. The Air Corps asked for other modifications, and the AT-6A/SNJ-3 emerged as the standard ad-vanced single-engine trainer for both services. (It was used for basic pilot training and even for primary training toward the end of World War II, when Nationalist Chinese students were sent to the States for pilot instruction.)

To accommodate orders that amounted to more than 600 aircraft when war began, North American opened a new plant in Dallas in 1942 to supplement the aircraft being turned out in the Los Angeles area.

The Dallas plant became the main point of manufacture - hence the name ‘Texan.” New model suffixes were assigned as minor changes were made. To save alu-minum, some of the AT-6/SNJs were turned out with plywood fuselages and internal stringers made from spruce. The Navy added tail hooks for carrier train-ing. Bomb racks and belly fuel tanks were also added.

A number of Texans were either built or modified for experimental purposes. The Army Air Forces ordered one XAT-6E in 1944 with an in-line, air-cooled engine installed. On test flights it reached a top speed of 244 mph and climbed to 30,000 feet - 50 mph faster and 6,000 feet higher than the Texans flying with radial en-gines. Unfortunately, the in-line engine proved to be a maintenance headache, and only one XAT-6E was built.


Another experimental Texan was des-ignated the ET-6F in 1950, when a swivel landing gear was installed to assist in making crosswind landings. The Northrop Co. experimented with automatic pilots in the T-6. Cameras were installed aft of the rear seat in a few aircraft for aerial photography; flares were added to make photography possible at night as well.

When the British realized they could not build enough trainers in the United Kingdom at the beginning of World War II, they ordered the BC-1, which they designated the Harvard Mark I. A single British machine gun for the right wing was specified, as well as British instruments and a circular control stick called a “spade.” The Canadians also ordered the Mark I, and one variant was labeled the AT-16. Since British engine mixture controls were reversed as far as Americans and Canadians were concerned, a warning plaque was installed that read: “This airplane has British carburetor mixture control. Lean—forward. Rich—back.”

The Harvard II was the equivalent to the USAAC’s AT-6A. The Harvard IIA was the equivalent to the USAAC’s AT-6C. Some were overhauled to a Mk.II* standard. This differed from the Mk.II in having a plywood and low alloy steel rear fuselage instead of the previous light alloy monocoque construction. This was said to save over 1200 lb of aluminium. The Mk.IIB was a version of the Mk.II built in Canada by the Noorduyn Aircraft Company, and known in the USA as the AT-16. The Harvard Mk.III reverted to all metal construction and had a 24volt electrical system. Two hundred and thirty five AT-6s were operated by Sweden and designated Sk-16.

The Harvard II (AT-6C), North American NA-16-1A, or North American NA-16-3 has a low-wing cantilever monoplane, the wing section varies from N.A.C.A. 2215 to 2209, in five sections, consisting of centre-section, two outer-sections and two wing-tips. The centre-section has parallel chord and thickness, outer-sections have back-swept leading-edge and straight trailing-edge and taper in thickness. Single-spar structure with spaced ribs and covered with a stressed aluminum alloy skin. Dynamically balanced ailerons, with aluminum-alloy frames and fabric covering. Split trailing-edge flaps inside ailerons and under fuselage. The fuselage is a welded chrome-molybdenum steel-tube framework with fittings integrally welded. The fuselage is constructed in four sections, engine-mounting, control-section, tail-section and monocoque bottom aft of wing. All sections bolted together. Side covering in form of fabric-covered aluminum-alloy frames bolted to fuselage. Cowling all metal and quickly removable.

Fitted with a cantilever tailplane and fin of metal, with sheet covering, the rudder and elevators have light-alloy frames, with fabric covering. Right and left sides of tail-plane and elevators are interchangeable. Metal surfaces are removable by externally-accessible bolts for internal inspection. Non-reversible trimming tabs on elevators. Fixed tab, adjustable of ground only, on rudder.

The undercarriage consists of two cantilever oleo struts, with the upper ends built into the ends of the centre-section by sleeves held by four bolts. The right and left units are interchangeable. Each unit enclosed in duralumin fairing, which does not enclose the streamline wheel, so that it is accessible for brake adjustment or removal. Hydraulically-operated wheel-brakes. Oleo-sprung steerable tail-wheel.

Power is from a Pratt & Whitney 600 hp radial, 9 cylinder or one Pratt & Whitney Wasp S3H1 nine-cylinder radial air-cooled engine, developing 550 hp at 5,000 ft (1,525 m) on welded chrome-molybdenum steel-tube mounting. NACA cowling. Fuel tanks (two), of welded aluminum alloy, in centre-section, one on each side of fuselage. Normal fuel capacity 104 U.S. gallons. Oil tank (9.5 U.S. gallons) in engine compartment and detachable with it. Alternative engines are the Pratt & Whitney Wasp R-1340-S1H1, Pratt & Whitney Wasp-Junior R-985 or the Wright Whirlwind R-975-E3.

Accommodation: Tandem cockpits, with sliding enclosures. Dual controls, with rear control quickly removable. Equipment may be installed to suit machine for training, fighting or light bombing. Provision made for installation of two fixed guns firing forward through airscrew and one gun on a movable mounting in back cockpit, bomb-rack below fuselage.

When it took over Noorduyn Aviation in 1946, CCF also acquired the production rights to the North American AT-16 Harvard trainer. Between 1941 and 1945 Noorduyn produced Harvard IIBs as advanced trainers, used to allow those who had become proficient on elementary trainers to graduate to single-engined operational aircraft. At the peak of production 83 Harvards per month were leaving the Noorduyn works and by the end of the war 2,800 had been completed, most being used by the RAF and RCAF, but some going as far afield as India, Australia and New Zealand.

 

Harvard-3
North American Harvard 3*


In 1951, after a gap of six years, the Harvard was again put into production when Can-Car's Fort William plant began to turn out the Harvard 4 to be used in training the pilots who might be needed in the Korean War or its aftermath. In total, 555 were built between 1951 and 1955, initially for the RCAF, but later for the USAF where they were designated T-6J. Some of the T-6Js were subsequently released for service with the West German Air Force.

 

NA-Harvard4
Harvard 4 / T.6J


The North American Aviation Co. granted rights to the Australians to manufacture the two-seat BC-1, which they called the “Wirraway,” a native word meaning “challenge.” It had twin machine guns in the nose, a flexible gun in the rear cockpit and could carry up to 500 pounds of bombs on underwing racks. The first Wirraways were rolled out in 1939. They saw heavy service during the first days of World War II as interceptors, fighter-bombers and long-range patrol aircraft, as well as observation craft.

After World War II, the U.S. Air Force changed many of its plane designations, and the “A” was dropped from the Texan’s identification. The T-6s were extremely active during the Korean War as spotter planes. Their pilots were officially known as forward air controllers, but their planes were popularly called “Mosquitoes,” since they harassed the Communist forces and specialized in locating enemy targets and guiding fighter-bombers in for airstrikes. They were also flown for air rescues and leaflet-dropping missions. Several were used as interceptors against the North Koreans, who were flying Soviet-made Polikarpov PO-2 night raiders. When remanufactured T-6s arrived with improved radios, underwing bomb and smoke-rocket racks and two pod-mounted machine guns, they were designated LT-6Gs. Numbers of T-6G's were being converted to LT-6G liaison aircraft by Ternco Corp in 1955. By the end of hostilities, the LT-6Gs had flown more than 40,000 sorties and logged about 117,500 combat hours.

The first Harvard Mk II used by the RCAF was delivered to Camp Borden in the summer of 1940. It was an anglicized version of the AT-6A, the differences being a lengthened exhaust stack, a fixed rear canopy section, an altered instrument panel and a British style control column. The Mk II was also fitted with the capability to hold a .303 calibre air operated machine gun on the starboard wing and a cine-camera in the port wing, with a gun-sight for the front cockpit. The plane was equipped with hardpoints under the wings in order to carry 8 practice bombs. The N.A. Harvard Mk.II was one of the most important single engine training aircraft of the British Commonwealth Air Training Plan. It was known as "the pilot maker" because of its important role in preparing pilots for combat.

After World War 2 the Mk.II Harvard was relegated to armament training and reserve squadron use, as the more modern Mk.IV came along. At the end of WW2, Harvard Mk.II's were used for Naval training in Nova Scotia. The approval for a Canadian Fleet Air Arm was not given by the government of the day until 1946. In January of 1947 Harvard Mk.II's began arriving in Dartmouth Nova Scotia for their stint as training aircraft for the newly formed Canadian Naval Air Arm. Much of the training was on gunnery exercises to prepare pilots for the deflection shots necessary with the gyro gun-sight of the Supermarine Seafire. Harvard Mk.II's were the planes chosen again for the training task. The course was similar to the one used to train RCAF pilots, with the exception of gunnery and formation training which was done on Seafires.

In December 1939, the RNZAF was allocated 105 Harvards, but the first aircraft didn't arrive until March 1941. The Harvard served in a wide variety of roles with the RNZAF, including flight training schools (2 FTS at Woodbourne being the biggest user), fighter squadrons, fighter operational training units, army co-operation squadrons, the Central Flying School and the Fighter Gunnery School.

After World War II, T-6s and SNJs were supplied to NATO nations such as France, West Germany, Italy and Belgium. Latin American pilots ferried many of the trainers home after they completed their training in the United States. For use in brush-fire wars, Texans were remanufactured with rocket and bomb racks and designated FT-6Gs. They were sent to such nations as Spain, Portugal, France and Brazil for counterinsurgency missions.

The Texan was phased out of U.S. Air Force and Navy inventories in 1958, but a number of T-6s were flown by the Civil Air Patrol into the 1960s. Although the American inventory during the Vietnam War showed no T-6s, armed Texans were flown briefly by Laotian and Cambodian pilots against Viet Cong targets along the Ho Chi Minh Trail.

A total of 17,096 of all models were built by North American in California, Texas, Montreal (by Noorduyn), Fort Frances, Ontario (by Canadian Car and Foundry), and in Australia as the Wirraway.

The aircraft is stressed for aerobatics and is capable of most maneuvers with the exception of sustained inverted flight, snap rolls, outside loops, and inverted spins.

The T-6/SNJ/Harvard aircraft have been produced in a number of model designations. Most of the changes are small. Fuel Capacity -   The T-6 has 110 gallons on all models except the T-6G and Harvard MK IV, which have 140 gallons. With a cruise fuel burn of 30 GPH, 110 gallons is adequate for most operators. Tail wheel steering/locking systems-  The Navy type is lockable only. The pilot is able to lock the tailwheel to a straight-ahead position for take off and landing. Steering is accomplished by differential braking. The steerable type system (also called P-51 type) uses an interconnect from the rudder pedals to the tailwheel steering system. This system allows the pilot to steer the aircraft by use of the rudder pedals. Full forward stick movement unlocks this system. When unlocked the tailwheel becomes full swivel and steering is again by differential braking. Either of these systems is adequate for most civilian operators. Hydraulic system -  The original system incorporated a pilot controlled bypass. In order to use the gear or flaps, a small button must first be pushed before activation of the system. This button pressurizes the system and a time delay circuit depressurizes the system after approximately 45 seconds. Later aircraft (TG-G/Harvard MK-4) had a modified linkage that engaged the system automatically. For practical purposes, either system is satisfactory. There are several variations in other areas such as instrument panel layout and cockpit glass. Many aircraft have been modified to incorporate various combinations of the above systems. 

 

Gallery


BC-1A
Engine: R-1340-45
Wingspan: 47 ft
Length: 27 ft
Max speed: 209 mph @ 5000 ft

 

A-27
Engine: 775hp Wright R-1820F
Wingspan: 42'0"
Length: 29'0"
Useful load: 1486 lb
Max speed: 250 mph
Cruise speed: 220 mph
Stall: 70 mph
Ceiling: 28,000'
Armament: 2x .30 nose guns and one flexible .30 rear cockpit
Bombload: 4 x 100 lb bombs underwing

 

AT-6A
Engine: Pratt & Whitney Wasp, 600 hp
Cruise: 120-145 kt
Vne: 205 kt

Harvard II / AT-6C / NA-16-1A / NA-16-3

Span 42 ft (12.8 m)
Length 27 ft. 5 3/16 in (8.38 m)
Height 8 ft 9 in (2.67 m)
Wing area 248 sq. ft (23 sq. m)
Weight empty 3,340 lb (1,515 kg)
Fuel and oil: 695 lb (315 kg)
Armament 141 lb (64 kg)
Weight loaded 4,556 lbs (2,065 kg)
Wing loading 185 lbs./sq. ft. (90 kg./sq. m)
Power loading 8.3 lbs./h.p. (3.71 kg./hp)
Speed at sea level 200 m.p.h. (324 kph)
Cruising speed at 12,000 ft. (3,660 m.) 185 mph. (298 kph)
Landing speed 61 mph (98 kph)
Maximum rate of climb 1,800 fpm (590 m/min.)
Service ceiling 26,000 ft. (7,930 m.)
Cruising range 680 miles (1,102 km)

T 6 / AT-16 Texan / Harvard

Engine: Pratt & Whitney Wasp R-1340 AN1, 542 hp
Length: 29.003 ft / 8.84 m
Height: 11.483 ft / 3.5 m
Wingspan: 41.995 ft / 12.8 m
Wing area: 252.954 sq.ft / 23.5 sq.m
Max take off weight: 5578.7 lb / 2530.0 kg
Weight empty: 4101.3 lb / 1860.0 kg
Max. weight carried: 1477.4 lb / 670.0 kg
Max. speed: 181 kt / 335 km/h
Initial climb rate: 1358.27 ft/min / 6.9 m/s
Service ceiling : 21654 ft / 6600 m
Wing load: 22.14 lb/sq.ft / 108.0 kg/sq.m
Range: 405 nm / 750 km
Endurance: 3 h
Crew: 2
Armament: 2 MG

T-6G
Engine: Pratt and Whitney R-1340-AN-1, 550 hp
Max speed, 212 mph (341 kph) at 5,000 ft (1524 m)
Cruise, 146 mph (235 kph)
Initial climb, 1,643 fpm. (8.3 m/sec)
Ceiling, 24,750ft (7 544 m)
Range, 870 mls (1400 km)
Empty weight, 4,271 lb (1937 kg)
Loaded weight, 5617 lb (2548 kg)
Span, 42 ft 0.25 in (12.8 m)
Length 29 ft 6 in (9 m)
Wing area 253.7 sq.ft (23.56 sq.m)

Harvard II
Engine: P&W R-1340-AN 1 Wasp, 550 hp
Span: 42ft (12.8m)
Length: 29ft(8.8m)
Max wt: 5617 lb (2547kg)
Speed: 212mph (341 kph)
Range: 870 sm(1400 km).

Harvard IIA
Engine: P&W R-1340-AN 1 Wasp, 550 hp.

Noorduyn Harvard Mk IIB
Engine: 600 hp Pratt & Whitney Wasp R-1340-AN-1
Maximum speed: 212 mph (341 km/h)
Service ceiling: 21,500 ft (6553 m)
Empty weight: 4,158 lb (1,886 kg)
Loaded weight: 5,617 lb (2,548 kg)
Span: 42 ft (12.8 m)
Length: 29 ft (8.8 m)
Height: 11 ft 8 in (3.5 m)
Wing area: 253.7 sq ft (23.6 sq m)

Harvard IIB

Engine: P&W R-1340-AN 1 Wasp, 550 hp.

Harvard III

Engine: P&W R-1340-AN 1 Wasp, 550 hp.

Harvard IV

Engine : Pratt & Whitney R-1340-AN-1, 600 hp
Wing Span : 42 ft 4 in
Length : 27 ft 11 in
Speed : 180 Mph (289 km/h)

 

Harvard 4 / T.6J
Basic trainer
Engine: 550 h.p. Pratt & Whitney R1340-ANI
Wingspan: 42 ft
Length: 29 ft.
Loaded weight: 5,617 lb.
Max. speed: 212 m.p.h.
Ceiling: 21,500 ft.
Range: 870 miles at 146 m.p.h.
Crew: 2.


Canadian Car and Foundry Harvard IV
Engine: Pratt & Whitney R-1340AN-1, 600 HP
Propeller: Hamilton Standard Two Blade 12D40
Wing Span: 42' 5"
Length: 29' 6"
Height: 11' 9"
Normal Gross Weight: 5300 lb
G Loading: +5.67, -2.33
Controls: Dual
Normal cruise: 155 MPH at 8000 ft
Fuel flow at cruise: 30 USGPH

SNJ-5 Texan

Powerplant: l x Pratt & Whitney R-1340-AN-1 Wasp, 410kW (550 hp)
Span: 12.81 m (42ft 0.25 in)
Length: 8.99m (29ft 6in)
Height: 3.58 m / 11 ft 9 in
Wing area: 23.57 sq.m / 253.71 sq ft
Armament: 2 or 3 x 7.62-mm (0.3-in) mg
Empty weight: 1886 kg / 4158 lb
Max T/O weight: 2404 kg (5,300 lb)
Max speed: 330 km/h / 205 mph at 5,000 ft
Ceiling: 6555 m / 21500 ft
Max range: 1200 km / 746 miles
Operational range: 750 miles
Crew: 2

harvard-ld

North American T-6 Texan / SNJ / Harvard

 

 


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