Thomas-Morse O-19 was an American observation biplane built by the Thomas-Morse Aircraft Company for the United States Army Air Corps.
O-19 was based on the earlier Thomas-Morse O-6 biplane. It was a conventional two-seat biplane of metal construction with fabric-covered wings and fixed tail surfaces. The design was evaluated with a number of different engine installations and the type was ordered into production as the O-19B with a Pratt & Whitney R-1340-7 Wasp radial engine.
Improved version of the XO-6 with a 450hp Pratt & Whitney R-1340-3 engine, one built.
Similar to the XO-19 with a 525hp Pratt & Whitney R-1690-1 engine, one built.
Similar to the XO-19 with a 600hp Curtiss H-1640-1 engine, one built later re-engined as the XO-21A
The XO-21 fitted with a 525hp Wright R-1750-1 engine.
Service evaluation aircraft with a 500hp Pratt & Whitney R-1340-9, two built.
O-19 without the 88 US Gallon main fuel tank, one built.
Production version with a 450hp Pratt & Whitney R-1340-7 engine, two machine-guns and modified cockpit, 70 built.
O-19B with tailwheel, ring cowl and minor changes, 71 built.
One O-19C converted as a VIP staff transport with dual controls.
O-19C with extended upper span wing and a 575hp Pratt & Whitney R-1340-15 engine, 30 built.
O-19 with 600hp Curtiss H-1640 Chieftain engine, one built, one converted.
XO-19 with a 600hp Curtiss V-1570-1 Conqueror engine, one built.
One O-19B re-engined with a 600hp Curtiss V-1570-11 engine and revised tail surfaces, one converted.
A sesqui-plane conversion of the Y1O-33 with a 600hp Curtiss V-1570-79 engine, one converted. Later modified by Consolidated Aircraft as their Model 23 and exported to Mexico
High-wing monoplane version of the Y1O-41, static test airframe only.
Specifications (O-19B) Edit Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 3000
Length: 28 ft 4 in (8.64 m)
Wingspan: 39 ft 9 in (12.12 m)
Height: 10 ft 6 in (3.20 m)
Wing area: 348 ft 2 (32.33 m 2)
Empty weight: 2722 lb (1235 kg)
Gross weight: 3800 lb (1724 kg)
Powerplant: 1 × Pratt & Whitney R-1340-7 Wasp radial piston engine, 450 hp (336 kW)
Maximum speed: 137 mph (220 km/h)
Service ceiling: 20,500 ft (6250 m)</ul>
Armament 2 x 0.3in (7.62mm) machine-guns (one fixed forward-firing, one movable in rear cockpit)
John Andrade, U.S.Military Aircraft Designations and Serials since 1909, Midland Counties Publications, 1979, ISBN 0-904597-22-9 (Page 137 and 138)
The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 3000