Pratt & Whitney R-1690 Hornet

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	Boeing 80 ; Lockheed Lodestar ; Sikorsky S-42 ; Vought O2U Corsair
Number built	2,944
Developed into	Pratt & Whitney R-1860 ; BMW 132 ; Mitsubishi Kinsei

The Pratt & Whitney R-1690 Hornet was a widely used American 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 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.

Variants

R-1690-3: 525 hp (391 kW)
R-1690-5: 525 hp (391 kW)
R-1690-11: 775 hp (578 kW)
R-1690-13: 625 hp (466 kW)
R-1690-S5D1G: 700 hp (520 kW)
R-1690-52: 750 hp (560 kW)
R-1690-SDG
R-1690-S1EG: 750 hp (560 kW)
R-1690-S2EG
R-1690-25: 850 hp (630 kW)
R-1690-S1C3G: 1,050 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 Hornet: License production of the Hornet in Germany, independently developed as the BMW 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
Gee Bee Model R-2 (1933)
Gee Bee R 1/2 Super Sportster
Granville-Miller-de Lackner R-6H “Q.E.D.”
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 BM
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.

Specifications (R-1690 S1E-G)

R-1690 with chamber walls cut away to show internal workings

Data from

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 cu in (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 (588 kW) at 2,300 rpm for takeoff
740 hp (550 kW) at 2,250 rpm at 7,000 ft (2,100 m)
Specific power: 0.47 hp/cu in (21.39 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)

References

Notes

Bibliography

Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X.

External links

Pratt & Whitney R-1690 page

Pratt & Whitney R-1690 Hornet

Variants

Applications

Engines on display