Search results
Results from the WOW.Com Content Network
The momentum theory or disk actuator theory – a theory describing a mathematical model of an ideal propeller – was developed by W.J.M. Rankine (1865), Alfred George Greenhill (1888) and Robert Edmund Froude (1889). The propeller is modelled as an infinitely thin disc, inducing a constant velocity along the axis of rotation.
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.
The momentum theory or disk actuator theory – a theory describing a mathematical model of an ideal propeller – was developed by W.J.M. Rankine (1865), A.G. Greenhill (1888) and R.E. Froude (1889). The propeller is modelled as an infinitely thin disc, inducing a constant velocity along the axis of rotation and creating a flow around the ...
Blade element momentum theory is a theory that combines both blade element theory and momentum theory. It is used to calculate the local forces on a propeller or wind-turbine blade. Blade element theory is combined with momentum theory to alleviate some of the difficulties in calculating the induced velocities at the rotor.
This is a two-bladed propeller 3 ft. in diameter, with a uniform geometrical pitch of 2.1 ft. (or a pitch-diameter ratio of 0.7). The blades have standard propeller sections based on the R.A.F-6 airfoil (Fig. 6), and the blade widths, thicknesses, and angles are as given in the first part of Table I.
An actuator disk accelerating a fluid flow from right to left. In fluid dynamics, momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by W.J.M. Rankine (1865), [1] Alfred George Greenhill (1888) and Robert Edmund Froude (1889).
A constant-speed propeller is a variable-pitch propeller that automatically changes its blade pitch in order to maintain a chosen rotational speed, regardless of the operational conditions of the aircraft. This is achieved by use of a constant-speed unit (CSU) or propeller governor, which automatically changes the propeller's blade pitch.
A Bonneville Dam Kaplan turbine after 61 years of service. The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed in 1913 by Austrian professor Viktor Kaplan, [1] who combined automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and water level.