For contra-rotating marine propellers, helicopter rotors and turbine fan blades, see Contra-rotating.
Aircraft equipped with contra-rotating propellers (CRP)[1]coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston engine or turboprop engine to drive a pair of coaxialpropellers in contra-rotation. Two propellers are arranged one behind the other, and power is transferred from the engine via a planetary gear or spur geartransmission. Contra-rotating propellers are also known as counter-rotating propellers,[2][3] although the term counter-rotating propellers is much more widely used when referring to airscrews on separate non-coaxial shafts turning in opposite directions.
^Sasaki, N.; Murakami, M.; Nozawa, K.; Soejima, S.; Shiraki, A.; Aono, T.; Fujimoto, T.; Funeno, I.; Ishii, N.; Onogi, H. (1998). "Design system for optimum contra-rotating propellers". Journal of Marine Science and Technology. 3 (1): 3–21. doi:10.1007/bf01239802. S2CID110551942.