Pratt & Whitney R-1535 Twin Wasp Junior
1930s American aircraft engine
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The Pratt & Whitney R-1535 Twin Wasp Junior is an American aircraft engine developed in the 1930s. The engine was introduced in 1932 as a 14-cylinder version of the 9-cylinder R-985, and was a two-row, air-cooled radial design. Displacement was 1,535 cu in (25.2 L); bore and stroke were both 5+3⁄16 in (132 mm).[1]
| R-1535 Twin Wasp Junior | |
|---|---|
| Pratt & Whitney Twin Wasp Junior, at the National Museum of Naval Aviation, Pensacola, Florida | |
| Type | Radial engine |
| National origin | United States |
| Manufacturer | Pratt & Whitney |
| First run | 1932 |
| Major applications | |
| Developed from | Pratt & Whitney R-985 Wasp Junior |
Variants
The following is a representative list of R-1535 variants. Data from a Pratt & Whitney designated-engine index and the U.S. Navy Aeronautical Engine Laboratory report index, unless otherwise noted.[2][3]
- R-1535-11 - 750 hp (560 kW)
- R-1535-13 - 750 hp (560 kW), 825 hp (615 kW)
- R-1535-44 - 625 hp (466 kW)
- R-1535-64 - 950 hp (710 kW)
- R-1535-72 - 700 hp (520 kW) for takeoff; 650 hp (480 kW) normal at 7,500 ft (2,300 m)
- R-1535-82 - 750 hp (560 kW)
- XR-1535-86 - 825 hp (615 kW); experimental fuel-injection variant
- XR-1535-88 - 825 hp (615 kW)
- R-1535-94 - 825 hp (615 kW)
- R-1535-96 - 825 hp (615 kW)
- R-1535-98 - 700 hp (520 kW)
- R-1535-SB4-G - 825 hp (615 kW)
Applications
Applications from the Aircraft Engine Historical Society, unless otherwise noted.[4]
- Bellanca 28-70
- Boeing XF6B
- Breguet 695
- Bristol Fairchild Bolingbroke Mk IVW
- Canadian Car and Foundry FDB-1
- Consolidated XB2Y
- Curtiss SBC-3 Helldiver
- Douglas O-46
- Fokker G.I (G.I The Wasp)
- Fokker D.XXI (Finnish licence-built series 4 and 5)
- Great Lakes BG
- Grumman F2F
- Grumman F3F-1
- Grumman XJF-1 Duck (prototype only)
- Grumman XSBF
- Grumman XSF-2
- Hughes H-1 Racer
- Miles Master
- Northrop 3A
- Northrop A-17
- Northrop BT
- Northrop XFT-2
- Potez 63.12[5]
- Vought SBU Corsair
- Vought SB2U Vindicator
- Vought V-141
- Vought XF3U
- Vought XO4U-2
Engines on display
- There is a R-1535-96 on display at the New England Air Museum, Bradley International Airport, Windsor Locks, CT.[6]
- There is an R-1535 on display at the San Diego Air and Space Museum. It is now being installed in the museum's Hughes H-1 Racer reproduction project.[citation needed]
- There is an R-1535 on display at Patria Group Linnavuori plant at Jyväskylä, Finland. It had belonged to Finnish Air Force Fokker D.XXI FR-137 [7]
Specifications (R-1535-SB4-G)
Data from [8]
General characteristics
- Type: Fourteen-cylinder two-row supercharged air-cooled radial engine
- Bore: 5+3⁄16 in (131.8 mm)
- Stroke: 5+3⁄16 in (131.8 mm)
- Displacement: 1,534.9 cu in (25.153 L)
- Length: 53.27 in (1,353 mm)
- Diameter: 44.13 in (1,121 mm)
- Dry weight: 1,087 lb (493 kg)
Components
- Valvetrain: Two overhead valves per cylinder
- Supercharger: Single-speed centrifugal type supercharger, 11:1 step-up
- Fuel system: Two-barrel Stromberg carburetor
- Fuel type: 87 octane rating gasoline
- Cooling system: Air-cooled
- Reduction gear: Epicyclic gearing, 0.75:1
Performance
- Power output: 825 hp (615 kW) at 2,625 rpm for takeoff
- Specific power: 0.54 hp/cu in (24.57 kW/L)
- Compression ratio: 6.75:1
- Specific fuel consumption: 0.49 lb/(hp•h) (295 g/(kW•h))
- Oil consumption: 0.39 oz/(hp•h) (15 g/(kW•h))
- Power-to-weight ratio: 0.76 hp/lb (1.25 kW/kg)
See also
Related development
- Pratt & Whitney R-985 Wasp Junior
- Pratt & Whitney R-1340 Wasp
- Pratt & Whitney R-1830 Twin Wasp
- Pratt & Whitney R-2800 Double Wasp
- Pratt & Whitney R-4360 Wasp Major
Comparable engines
Related lists
