The Consolidated Model 21 was an American two-seat training aircraft built by the Consolidated Aircraft Company.
It was used by the United States Army Air Corps with the designation PT-11 and the United States Coast Guard under the designation N4Y.
The Model 21 was an aerodynamic cleaned up version of the Model 12/PT-3, one of the distinguishing features being curved instead of angular tail surfaces.
The aircraft was a single engined biplane with fixed tailwheel landing gear and accommodation for two in open cockpits.
Designated the PT-11 by the United States Army Air Corps it progressed through a number of trial variants but was not built in large numbers.
11 Examples of the model 21-C were built in Canada as the 21-M for Mexico, none were built for local use.
Variants
XPT-933/Model 21A
Prototype powered by 170 hp (130 kW) Kinner engine, first flew February 1931.
YPT-11
Evaluation aircraft for US Army based on the Model 21A with a 165 hp (123 kW) Continental R-545-1 engine.
PT-11A
One YPT-11 was re-engine with a 175 hp (130 kW) Curtiss R-600-1 Challenger engine, originally as Y1PT-11A, later converted to PT-11C standard.
Y1PT-11B
One YPT-11 was re-engine with a 210 hp (160 kW) Kinner YR-720-1 engine and designated Y1PT-11B.
5 production aircraft for US Army with another for the United States Coast Guard and designated N4Y-1.
PT-11C
PT-11A re-engine with a 180 hp (130 kW) Lycoming YR-680-1 engine.
One or two converted for US Army, with 18 new-build aircraft for Colombia.
PT-11D
Production version with 220 hp (160 kW) R-680-3 engine, originally designated Y1PT-11D.
PT-12
A version of the PT-11 with a 300hp R-985-1 engine and detailed changes, later redesignated BT-7.
Y1BT-6
One YPT-11 was re-engine with a 300hp R-985-1
BT-6
Redesignation of Y1BT-6.
BT-7
PT-12 aircraft redesignated.
XN4Y-1
Evaluation aircraft for the United States Coast Guard, three built.
N4Y-1
One YPT-11B for the USCG, later modified to the same standard as the XN4Y-1
Specifications
Crew
Two
Length
26 ft 11 in (8.20 m)
Wingspan
31 ft 7 in (9.63 m)
Height
9 ft 8 in (2.95 m)
Wing area
280 sq ft (26.01 m2)
Empty weight
1,918 lb (870 kg)
Max take-off weight
2,585 lb (1,173 kg)
Powerplant
1 × Lycoming R-680A radial piston, 200 hp (149 kW)
