To counteract torque this two-bladed-rotor experimental helicopter used not a conventional tail rotor but a jet thrust system. The latter consisted of a fan blower placed just behind the engine with a 'stove pipe' tail forward. Air was thus forced under pressure through the hollow fuselage into a tail orifice where vanes directed the jet thrust laterally.
Main rotor torque was effectively overcome, but this torque compensation system's power requirements proved markedly excessive at speeds greater than 64km/h.
P.Lambermont "Helicopters and Autogyros of the World", 1958
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J.P.Spencer "Whirlybirds: A History of the U.S. Helicopter Pioneers", 1998