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A 6-bladed Hamilton Standard 568F propeller on an ATR 72 short-haul airliner. Lowry [27] quotes a propeller efficiency of about 73.5% at cruise for a Cessna 172.This is derived from his "Bootstrap approach" for analyzing the performance of light general aviation aircraft using fixed pitch or constant speed propellers.
Alternatively, a constant-speed propeller is one where the pilot sets the desired engine speed , and the blade pitch is controlled automatically without the pilot's intervention so that the rotational speed remains constant. The device which controls the propeller pitch and thus speed is called a propeller governor or constant speed unit.
Once the pilot has set the desired propeller speed, the propeller governor maintains that propeller speed by adjusting the pitch of the propeller blades, using the engine's oil pressure to move a hydraulic piston in the propeller hub. Many modern aircraft use single-lever power control (SLPC) system, where on-board computer automatically ...
Later advances included full-feathering and reversible propellers. Hamilton Standard was a division of United Aircraft Corporation (1934) along with Pratt & Whitney (engines). In the early 1950s Hamilton developed the technology to accurately meter fuel in jet engines, and its fuel controls were employed on Boeing 707s and Douglas DC-8s , as ...
Counter-rotating propellers World War I Linke-Hofmann R.I German heavy bomber (1917) with counter-rotating propellers He 177A Greif with counter-rotating propellers. Counter-rotating propellers (CRP) are propellers which turn in opposite directions to each other. [1] They are used on some twin- and multi-engine propeller-driven aircraft.
The rate of rotation of an aircraft propeller, meanwhile, especially before the advent of the constant-speed propeller, could vary widely, depending on the throttle setting and what maneuvers were being performed. Even if it had been feasible to pick a particular point on an aircraft engine's tachometer at which a machine gun's cyclic rate ...
The earliest known examples of "push-pull" engined-layout aircraft was the Short Tandem Twin.. An early pre-World War I example of a "push-pull" aircraft was the Caproni Ca.1 of 1914 which had two wing-mounted tractor propellers and one centre-mounted pusher propeller.
An alternative design is the controllable-pitch propeller (CPP, or CRP for controllable-reversible pitch), where the blades are rotated normally to the drive shaft by additional machinery – usually hydraulics – at the hub and control linkages running down the shaft. This allows the drive machinery to operate at a constant speed while the ...