Ford 3-AT / 4-AT / 5-AT / Tri-Motor / C-3 / C-4 / C-9 / JR / RR / XB-906-1 / 9-AT / 11-AT / 13-A / 14-A

The original Stout Metal Airplane Company was purchased in 1925 by Henry Ford and the new division of the Ford Motor Company produced three versions of the Tri-Motor monoplane. The Tri-Motor’s fuselage was constructed from a series of transverse duralumin bulkheads covered with corrugated metal skin. One engine was mounted in the nose, while the other two were suspended underneath the wings.

In 1926 Ford told Stout to build him a tri-motor. Stout rushed through his Model 3-AT and the resulting Model 3-AT was a crude and unimpressive lash-up. It may have flown only once before it was destroyed in a fire on the ground, which also destroyed the factory at Ford Airport, on 17 January 1926. Ford and Stout had a violent argument which ended in Stout being fired. In February 1926 Ford decided to proceed with an improved aircraft, the Model 4-AT, whose design was based on that of the Model 3-AT but differed in almost all details and especially in the engine installations, cockpit, landing gear and fuselage. The small engineering team was headed by Harold Hicks and Tom Towle. The first of the successful Ford tri-motors, NC1492, was flown for the first time on 11 June 1926.

Ford 4-AT-A 

The wing was recessed so that the three spars significantly reduced headroom in the cabin. Each spar was a Warren-braced truss assembled mainly by riveting, and the ribs were likewise built up from rolled strip and sections. The wing suffered a certain amount of cracking after flying over 5,000 hours. The wing was made in three parts, the rectangular centre section being integral with the fuselage. The latter was a capacious box. The three engines, which in the Model 4-AT were 149-kW (200-hp) Wright J-4 Whirlwinds driving two-blade metal propellers, were uncowled and in most Fords not even provided with cooling airflow baffles or fairings. In the Model 3-AT the nose engine had been mounted low to balance the thrust lines of the two wing-mounted engines, but in the Model 4-AT the centre engine was mounted exactly on the nose and the other pair brought down so that all thrust lines were at the same level, the wing engines now being carried on the front of separate strut-mounted nacelles well below the wihg. The wing engines had short stub exhausts or, from 1927, an exhaust manifold leading to a short pipe on the outboard side of the nacelle. The nose engine, how-ever, sent its gas through a pipe running (in most versions) half way back to the tail, surrounded by a muff open at the front so that, in cold weather, heated fresh air could be admitted to the cabin. The movable control surfaces, as well as the fixed tail, were metal-skinned. The extreme nose and the top and bottom of the fuselage were often skinned with smooth metal sheet.

From the first Model 4-AT, the skin material used was Alclad, duralumin coated with non-corrosive pure aluminium, spray coated in varnish. All the Fords had an oval entrance door on the right side, used for passengers, cargo and also by the two pilots. In the Model 4-AT the latter had the usual open cockpit, a feature of which was a sharply angled Vee windshield with glass panes that were not vertical but sloped outwards from bottom to top, to give a better view for landing. Panels in the windshield could be slid open in really bad weather. The Model 4-AT had four passenger seats on each side of a central aisle, and was available with a lavatory at the rear. Light personal baggage could be placed in a typical suspended-mesh rack along each side of the cabin above the windows, level with the bottoms of the wing spars. In a few Model 4-ATs further baggage and mail was stowed in drop-down lockers between the spars at the inner end of each outer wing panel, though this was really a feature of later models. Other features were wheel brakes, which enabled a tailwheel to be used instead of a skid, and an electrical system with the battery charged by a generator on the nose engine. This system served navigation lights and, in most aircraft, leading-edge landing lamps and two-way radio. On the other hand, the Fords adhered to the old practice of running the tail control cables along the outside of the fuselage from large rocker arms on the sides of the nose.

One of the first customers was Stout Air Services to fly schedules from Detroit to Chicago and other cities in the Great Lakes region.

Twenty-five of the 1929 4-AT-E (ATC 132) were built, selling for $42,000. Some were 4-AT-B conversions. Seven went to the AAC as C-3A, and two to USN as JR. One as the XJR-1 (A7526) and five production model as the JR-2 (A8273-8274), re-designated as RR-2 later.

Subsequent Fords had an enclosed cockpit with sliding side windows, and various other refinements, and almost all were more powerful. As listed in the separate variants section, there were almost as many sub-types as there were aircraft built, partly because there were numerous rebuilds and conversions. The initial Model 4-AT-A eight-seater entered service with Ford’s own air service on 2 August 1926. Ford Airport at Dearborn had by this time become the first in the world with paved runways and full electric lighting, and later Ford not only made other improvements to the buildings but also set up one of the world’s first training schools for commercial flight crews.

Though the Model 4-AT had been the biggest all-metal aircraft then built in the USA, and possibly in the world, it was rightly judged too small and the Model 4-AT-B of 1927 had a span increased from 20.97m (68ft l0in) to 22.53m (73ft 11in), matching the greater power of 164-kW (220-hp) J-6 Whirlwind engines. Though the fuselage was almost the same as before, the seating limit went up to 12. There followed various sub-types of Model 4-AT, differing chiefly in engine arrangement. Almost all the Fords were originally built with spatted main wheels, and their modern image did much to promote sales.

Four went to the USN/USMC as JR-3/RR-4. (ATC 2-240) and (ATC 2-242) for 15 passengers with 420hp Wasp as 5-AT-C Special.

 Variants:

Gallery

Specifications:

7 conversions (29-220-226)