Contra-rotating

<h2 id="aircraft-propulsion-and-lift">Aircraft propulsion and lift</h2>
<p class="note">Main article: <a href="/facts/Contra-rotating_propellers/1l6S03PW">Contra-rotating propellers</a></p>
<p>While several nations experimented with contra-rotating propellers in aircraft, only the United Kingdom and Soviet Union produced them in large numbers. The U.S. worked with several prototypes, including the <a href="/facts/Tailsitter/P2apcDzQ">tail-sitting</a> <a href="/facts/Convair_XFY/vTDPI1Id">Convair XFY</a> and <a href="/facts/Lockheed_XFV/1rnjpokA">Lockheed XFV</a> "Pogo" <a href="/facts/Vertical_takeoff_and_landing/Y7CSmfCm">VTOL</a> fighters, but <a href="/facts/Jet_engine/CJjFpeqt">jet engine</a> technology was advancing rapidly and the designs were deemed unnecessary.
</p><p>Some helicopters use contra-rotating <a href="/facts/Coaxial_rotors/wj34vBUg">coaxial rotors</a> mounted one above the other.  The <a href="/facts/H-43_Huskie/NNMesG7U">H-43 Huskie</a> helicopter uses non-coaxial <a href="/facts/Intermeshing_rotors/hfWtWoIr">intermeshing rotors</a> turning in opposite directions.
</p><p>The <a href="/facts/F-35_Lightning_II/x0NWsvfC">F-35B</a> variant of the <a href="/facts/F-35_Lightning_II/x0NWsvfC">F-35 Lightning II</a> strike fighter uses a lift fan with contra-rotating blades.
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Contra-rotating_marine_propellers/jKHVtJuR">Contra-rotating marine propellers</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://books.google.com/books?id=hCcDAAAAMBAJ&pg=PA111">Two Propellers in Tandem Turning in Opposite Ways Give Warplane New Speed<i></i></a></li></ul>

Contra-rotating open-in-new

Contra-rotating