The one Thomas-Morse M-23 built, in 1923, for Army evaluation was a single place open cockpit biplane. All-metal, corrugated-skin pursuit design, it had inherent design and cooling problems despite several modifications. It was evaluated at McCook Field but rejected for its flight characteristics and high landing speed. It was dismantled in 1926.

Engine: Curtiss D-12, 440 hp
Wingspan: 19’6″ (later 23’0″)
Length: 16’8″ (later 17’6″)
Useful load: 788 lb
Max speed: 167 mph
Cruise speed 125 mph
Stall: 80 mph
Range: 280 mi
Ceiling: 20,150′
Seats: 1

The 1923 Thomas-Morse S-9 Army trainer was a widened side-by-side cockpit in an all-metal corrugated fuselage, with wings from S-6 and tail from S-4C.

Only one was built but during Army flight tests at Kelly Field TX, it showed structural problems and the pilot bailed out; however, the plane reportedly glided to an “almost-successful landing” except for losing its wings when it went between two trees. It was sent back to Thomas-Morse, but never repaired.

Engine: 200hp Lawrance J-1
Max speed: 140 mph
Stall: 40 mph
Seats: 2

The Thomas-Morse S-6 of 1919 was Thomas-Morse’s only production with tandem cockpits and dual controls. The one built, NC98, was used in racing competitions, placed second in the 1919 Nationals.

Engine: LeRhône, 80hp
Wingspan: 29’0″
Length: 27’4″
Max speed: 105 mph
Stall: 35 mph
Ceiling: 19,500′
Seats: 2

The 1926 Thomas-Morse O-6 is a metal-frame versions of Douglas O-2 built by Thomas-Morse under government contract. One went to McCook Field for testing as P-439 (25-435), and with a 435hp Liberty V-1650-1 was re-designated as O-6 (25-436).

Three production O-6 were built (25-437/439) with Liberty 12 engines.

The XO-6B of 1925 was a re-design of the O-6 with a 450hp P&W R-1340, revised wing covering and bracing, corrugated metal fuselage skin. One (25-440) was built as the prototype for O-19, McCook tested it as P-503.