Pratt & Whitney R-1690 Hornet
Pratt & Whitney R-1690 Hornet
R-1690 Hornet | |
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Pratt & Whitney Hornet, at the Deutsches Museum, Munich. | |
Type | Radial engine |
National origin | United States |
Manufacturer | Pratt & Whitney |
First run | June 1926 |
Major applications | Lockheed Lodestar O2U Corsair Sikorsky S-42 |
Number built | 2,944 |
Developed into | Pratt & Whitney R-1860 BMW 132 |
The Pratt & Whitney R-1690 Hornet was a widely used aircraft engine. Developed by Pratt & Whitney, 2,944 were produced from 1926 through 1942.[1] 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 license 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 Hornet | |
---|---|
Pratt & Whitney Hornet, at the Deutsches Museum, Munich. | |
Type | Radial engine |
National origin | United States |
Manufacturer | Pratt & Whitney |
First run | June 1926 |
Major applications | Lockheed Lodestar O2U Corsair Sikorsky S-42 |
Number built | 2,944 |
Developed into | Pratt & Whitney R-1860 BMW 132 |
Variants
- R-1690-3525 hp (392 kW)R-1690-5525 hp (392 kW)R-1690-11775 hp (578 kW)R-1690-13625 hp (466 kW)R-1690-S5D1G700 hp (522 kW)R-1690-52750 hp (559 kW)R-1690-SDGR-1690-S1EG750 hp (559 kW)R-1690-S2EGR-1690-25850 hp (634 kW)R-1690-S1C3G1,050 hp (780 kW)Fiat A.59 R.License built in Italy with reduction gearing.Fiat A.59 R.C.License built in Italy with reduction gearing and supercharger.BMW HornetLicense production of the Hornet inGermany, independently developed as theBMW 132.
Applications
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
Engines on display
There is a R-1690 on display at the New England Air Museum, Bradley International Airport, Windsor Locks, CT.[2]
Specifications (R-1690 S1E-G)

R-1690 with chamber walls cut away to show internal workings
Data from [3]
General characteristics
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)
Components
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
Performance
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)
See also
Related development
BMW 132
Mitsubishi Kinsei
Pratt & Whitney R-2180-A Twin Hornet
Comparable engines
Bristol Pegasus
Wright R-1750
Related lists
List of aircraft engines