Thomas-Morse O-19

The Thomas-Morse O-19 was an American observation biplane built by the Thomas-Morse Aircraft Company for the United States Army Air Corps.

Development
The 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 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.

Variants

 * XO-19
 * Improved version of the XO-6 with a 450 hp (340 kW) Pratt & Whitney R-1340-3 engine, one built.


 * YO-20
 * Similar to the XO-19 with a 525 hp (391 kW) Pratt & Whitney R-1690-1 engine, one built.


 * XO-21
 * Similar to the XO-19 with a 600 hp (450 kW) Curtiss H-1640-1 engine, one built, later re-engined as the XO-21A.


 * XO-21A
 * The XO-21 fitted with a 525 hp (391 kW) Wright R-1750-1 engine.


 * O-19
 * Service evaluation aircraft with a 500 hp (370 kW) Pratt & Whitney R-1340-9, two built.


 * O-19A
 * O-19 without the 88 US Gallon main fuel tank, one built.


 * O-19B
 * Production version with a 450 hp (340 kW) Pratt & Whitney R-1340-7 engine, two machine-guns and modified cockpit, 70 built.


 * O-19C
 * O-19B with tailwheel, ring cowl and minor changes, 71 built.


 * O-19D
 * One O-19C converted as a VIP staff transport with dual controls.


 * O-19E
 * O-19C with extended upper-span wing and a 575 hp (429 kW) Pratt & Whitney R-1340-15 engine, 30 built.


 * O-21
 * O-19 with 600 hp (450 kW) Curtiss H-1640 Chieftain engine, one built, one converted.


 * YO-23
 * XO-19 with a 600 hp (450 kW) Curtiss V-1570-1 Conqueror engine, one built.


 * Y1O-33
 * One O-19B re-engined with a 600 hp (450 kW) Curtiss V-1570-11 engine and revised tail surfaces, one converted.


 * Y1O-41
 * A sesqui-plane conversion of the Y1O-33 with a 600 hp (450 kW) Curtiss V-1570-79 engine, one converted. Later modified by Consolidated Aircraft as their Model 23 and exported to Mexico.


 * Y1O-42
 * High-wing monoplane version of the Y1O-41, static test airframe only.