page_title: Contra-rotating propellers
section_title: United States
hierarchical_section_title: Contra-rotating propellers / Use in aircraft / United States
caption_attribution_description: English: B-42 Mixmaster
context_page_description: Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston or turboprop engine to drive two coaxial propellers in contra-rotation. Two propellers are arranged one behind the other, and power is transferred from the engine via a planetary gear or spur gear transmission. Contra-rotating propellers are also known as counter-rotating propellers, although counter-rotating propellers is much more widely used when referring to airscrews on separate shafts turning in opposite directions.
context_section_description: The United States worked with several prototypes, including the Northrop XB-35, XB-42 Mixmaster, the Douglas XTB2D Skypirate, the Curtiss XBTC, the A2J Super Savage, the Boeing XF8B, the XP-56 Black Bullet, the Fisher P-75 Eagle and the tail-sitting Convair XFY "Pogo" and Lockheed XFV "Salmon" VTOL fighters and the Hughes XF-11 reconnaissance plane. The Convair R3Y Tradewind flying boat entered service with contra-rotating propellers. However, both piston-engined and turboprop-powered propeller-driven aircraft were reaching their zenith and new technological developments such as the advent of the pure turbojet and turbofan engines, both without propellers, meant that the designs were quickly eclipsed.
  The US propeller manufacturer, Hamilton Standard, bought a Fairey Gannet in 1983 to study the effects of counter rotation on propeller noise and blade vibratory stresses. The Gannet was particularly suitable because the independently-driven propellers provided a comparison between counter and single rotation.
caption: Douglas XB-42 Mixmaster
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