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Phase shift torque meters can measure shaft power to 0.1% accuracy in R & D applications, and to 1.0% when designed for permanent installation, both at confidence levels of 95%. [ 3 ] As of 1991, phase shift torque measurement instrumentation had been installed on gas turbine systems with a total power of 2 GW, with over 2 million operational ...
A prop-shaft assembly consists of a propeller shaft, a slip joint and one or more universal joints. Where the engine and axles are separated from each other, as on four-wheel drive and rear-wheel drive vehicles, it is the propeller shaft that serves to transmit the drive force generated by the engine to the axles.
These "pneumatic" propellers were fitted on the de Havilland DH.88 Comet aircraft, winner of the famed long-distance 1934 MacRobertson Air Race and in the Caudron C.460 winner of the 1936 National Air Races, flown by Michel Détroyat . Use of these pneumatic propellers required presetting the propeller to fine pitch prior to take-off.
Throughout the mid-20th century, Sensenich wood props were available on nearly all 1-seat and 2-seat U.S.-made aircraft, many of which still operate today. Sensenich expanded into airboat propellers in 1949, establishing a second factory for that market at Plant City, Florida under the name Sensenich Wood Propeller Company .
The torque on the aircraft from a pair of contra-rotating propellers effectively cancels out. Contra-rotating propellers have been found to be between 6% and 16% more efficient than normal propellers. [4] However they can be very noisy, with increases in noise in the axial (forward and aft) direction of up to 30 dB, and tangentially 10 dB. [4]
Propellers can have a single blade, but in practice there is nearly always more than one so as to balance the forces involved. Archimedes' screw The origin of the screw propeller starts at least as early as Archimedes (c. 287 – c. 212 BC), who used a screw to lift water for irrigation and bailing boats, so famously that it became known as ...
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A Soviet Ka-32 helicopter with coaxial contra-rotating rotors, in 1989. Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque.