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Pratt and Whitney R 1535 Twin Wasp Junior

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Pratt & Whitney R-1535 Twin Wasp Junior

The Pratt & Whitney R-1535 Twin Wasp Junior was an engine used in American aircraft in the 1930s. The engine was first introduced in 1932 as a 14-cylinder version of the 9-cylinder R-985. It was a two-row, air-cooled radial design. Displacement was 1,535 in³ (25.2 L); bore and stroke were both 5-3/16 in (131.8 mm).

Contents

Variants

  • R-1535-11 - 750 hp (559 kW)
  • R-1535-13 - 750 hp (559 kW), 825 hp (615 kW)
  • R-1535-44 - 625 hp (466 kW)
  • R-1535-72 - 650 hp (485 kW)
  • R-1535-94 - 825 hp (615 kW)
  • R-1535-96 - 825 hp (615 kW)
  • R-1535-98 - 700 hp (521 kW)
  • R-1535-SB4-G - 825 hp (615 kW)

    • Applications

  • Bellanca 28-70
  • Boeing XF6B
  • Breguet 695
  • Canadian Car and Foundry FDB-1
  • Consolidated XB2Y
  • Curtiss SBC-3 Helldiver
  • Douglas O-46
  • 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 A-17
  • Northrop BT
  • Northrop XFT-2
  • 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.
  • There is an R-1535 on display at the San Diego Air and Space Museum.

    • Specifications (R-1535-SB4-G)

    Data from

    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 in³ (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 reduction
  • 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/in³ (24.45 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)

    • References

    Pratt & Whitney R-1535 Twin Wasp Junior Wikipedia
    (Text) CC BY-SA