[2] The T-840 was powered by two 420 hp (313 kW) Wright R-975 9-cylinder radial engines, mounted well forward and above the wing leading edge and enclosed in wide chord NACA cowlings.

The control surfaces had metal structures and fabric covering; both elevators and rudder carried flight adjustable trim tabs.

[2] The fuselage was flat sided, with the cabin seating the crew side-by-side just ahead of the wing leading edge but well behind the propeller plane.

[2] The mainwheels of the fixed tricycle undercarriage were mounted on almost horizontal V-form half-axles from the bottom corner of the fuselage, with vertical oleo-pneumatic shock absorber legs joining axles to the wing underside aft of the engines.

[2] At the time of the first flight in February 1938, from the Timm works at Grand Central Air Terminal, Glendale, California, the wheels were not in fairings[3] but later these were fitted.