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 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 1535 cuin; bore and stroke were both 5+3/16 in.

Variants

 * R-1535-11 - 750 hp
 * R-1535-13 - 750 hp, 825 hp
 * R-1535-44 - 625 hp
 * R-1535-72 - 650 hp
 * R-1535-94 - 825 hp
 * R-1535-96 - 825 hp
 * R-1535-98 - 700 hp
 * R-1535-SB4-G - 825 hp

Applications
• Bellanca 28-70

• Boeing XF6B

• Breguet 695

• Bristol Bolingbroke

• 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 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.