Pratt & Whitney R-1535 Twin Wasp Junior

The Pratt & Whitney R -1535 Twin Wasp Junior was an aircraft engine of the U.S. manufacturer Pratt & Whitney from 1932., The R -1535 was the first two-row radial engine P & W and predecessor of up to 1951 in large numbers built R- 1830 Twin Wasp.

The Twin Wasp Junior was an air-cooled 14 - cylinder twin-row radial engine with a displacement of 1535 cubic inches (about 25.2 liters). His performance was approximately that of the 9-cylinder radial engine R- 1690 Hornet, of which he, inter alia, to distinguished by a smaller diameter. Since he was, however, more difficult and expensive, he found few buyers.

Variants

  • R -1535: 700 hp ( 521 kW)
  • R -1535 -13: 750 hp ( 559 kW) or 825 hp ( 615 kW)
  • R -1535 -SB4 -G: 825 hp ( 615 kW)

Use (selection)

  • Hughes H-1
  • Douglas O -46
  • Fokker D.XXI
  • Grumman F2F
  • Vought Vindicator SB2U

Technical data (R -1535 -SB4 -G)

  • Type: air-cooled two-row 14 - cylinder radial engine with supercharging ( centrifugal )
  • Bore: 132 mm
  • Stroke: 132 mm
  • Capacity: 25.15 l
  • Power: 615 kW ( 825 hp) at 2.625/min
  • Compression ratio: 6,75:1
  • Length: 1353 mm
  • Diameter: 1121 mm
  • Weight: 493 kg
Hughes H-1 Racer Douglas O-46 Vought SB2U Vindicator
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