The Pratt & Whitney R-1690 Hornet was a widely used aircraft engine. Developed by Pratt & Whitney, 2,944 were produced from 1926 through 1942. It first flew in 1927. It was a single-row, 9-cylinder air-cooled radial design. Displacement was 1,690 cubic inches (27.7 L). It was built under licence in Italy as the Fiat A.59. In Germany, the BMW 132 was a developed version of this engine. The R-1860 Hornet B was an enlarged version produced from 1929.
R-1690-3
525 hp (392 kW)
R-1690-5
525 hp (392 kW)
R-1690-11
775 hp (578 kW)
R-1690-13
625 hp (466 kW)
R-1690-S5D1G
700 hp (522 kW)
R-1690-52
750 hp (559 kW)
R-1690-SDG
R-1690-S1EG
750 hp (559 kW)
R-1690-S2EG
R-1690-25
850 hp (634 kW)
R-1690-S1C3G
1,050 hp (780 kW)
Fiat A.59 R.
Licence built in Italy with reduction gearing.
Fiat A.59 R.C.
Licence built in Italy with reduction gearing and supercharger.
BMW Hornet
Licence production of the Hornet in Germany, independently developed as the BMW 132.
Bach Air Yacht
Bellanca 31-40
Boeing 80
Boeing Model 95
Boeing Model 299
Burnelli UB-14
Douglas O-38
Focke-Wulf Fw 200 V1
Junkers Ju-52
Junkers Ju 86
Junkers W 34
Keystone B-3
Lockheed Model 14 Super Electra (L-14H)
Lockheed Lodestar (C-56A, C-56B, C-56C, C-56D, C-56E, C-59/Mk 1a)
Martin XB-14
Vought O2U Corsair
Sikorsky S-40A
Sikorsky S-42
Sikorsky S-43
Wedell-Williams Model 44
There is a R-1690 on display at the New England Air Museum, Bradley International Airport, Windsor Locks, CT.
Data from
Type: Nine-cylinder single-row supercharged air-cooled radial engine
Bore: 6 1⁄8 in (155.6 mm)
Stroke: 6 3⁄8 in (161.9 mm)
Displacement: 1,690.5 in³ (27.7 l)
Length: 50.98 in (1,295 mm)
Diameter: 54.41 in (1,382 mm)
Dry weight: 1,014 lb (460 kg)
Valvetrain: Pushrod-actuated
Supercharger: Single-speed centrifugal type supercharger, 12.0:1 gear ratio
Fuel system: Two-barrel Stromberg carburetor
Fuel type: 87 octane rating gasoline
Cooling system: Air-cooled
Reduction gear: Epicyclic gearing, 2:3
Power output:
789 hp (589 kW) at 2,300 rpm for takeoff
740 hp (552 kW) at 2,250 rpm at 7,000 ft (2,135 m)
Specific power: 0.47 hp/in³ (21.26 kW/l)
Compression ratio: 6.0:1
Specific fuel consumption: 0.6 lb/(hp•h) (362 g/(kW•h))
Oil consumption: 0.42 oz/(hp•h) (16 g/(kW•h))
Power-to-weight ratio: 0.78 hp/lb (1.28 kW/kg)
