Abstract: A propeller pitch control apparatus for an aircraft in which the vector sum of the aircraft forward speed and the propeller rotational tip speed is a selected fraction of the speed of sound, the fraction based on percent power and altitude, to maximize efficiency and minimize noise.

Abstract: A fluid energy turbine has a radial flow rotor in which fluid driven blades are peripherally distributed about a horizontal axis and in which auxiliary-biased outlet gates are provided for release of high fluid pressures to govern turbine speed such as in high windstorms.

Abstract: An active control device for use on an aerodynamic structure is provided. The aerodynamic structure includes an outer aerodynamic skin and an interior volume, wherein the outer aerodynamic skin surrounds the interior volume. The active control device includes at least one aperture disposed on the outer aerodynamic skin and a diaphragm disposed in the interior volume of the aerodynamic structure. The at least one aperture connects the outer aerodynamic skin to the interior volume, and the diaphragm in the interior volume is movable between a first position and a second position. Movement of the diaphragm from the first position to the second position pushes air through the at least one aperture and out of the interior volume. Movement of the diaphragm from the second position to the first position draws air through the at least one aperture and into the interior volume. The diaphragm may be circular, or may be oval-shaped.

Abstract: A wind energy turbine having air driven blades peripherally distributed about a horizontal rotational axis forming an interior region in which air pressures built up by wind introduced thereto are released through the spaces between the blades. The rotor is rotatably supported by rollers on a pair of parallel front and back stationary tubular rings which act as tracks for the rotor. An aerodynamically contoured entry ring at the front side of the rotor promotes smooth flow of air to the rotor interior and covers the front side ring and rollers mated therewith.

Abstract: Apparatus for peripherally supporting the rotor of a fluid driven turbine and for power take-off of energy by transformation of peripheral speed of the rotor to use such as to drive one or more electric generators to provide electric power output as determined by available wind energy.

Abstract: A wind energy turbine having air driven blades peripherally distributed about a horizontal rotational axis forming an interior region in which air pressures built up by wind introduced thereto are released through the spaces between the blades. A stationary back wall for the rotor includes biased air outlet gates for auxiliary release of high internal air pressures thereby limiting and governing rotational speed of the turbine such as in high storm winds. The rotor is rotatably supported by rollers on a pair of parallel stationary rings which act as tracks for the rotor. The entire rotor support assembly is mounted on a platform pivotable about a vertical axis by an associated wind vane arrangement for directing the turbine entry into oncoming winds.

Abstract: A support for peripherally supporting the rotor of a fluid driven turbine and for power take-off of energy by transformation of peripheral speed of the rotor to use such as to drive one or more electric generators to provide electric power output as determined by available wind energy.

Abstract: A fluid energy turbine has a radial flow rotor in which fluid driven blades are peripherally distributed about a horizontal axis and in which auxiliary biased outlet gates are provided for release of high fluid pressures to govern turbine speed such as in high storm winds. The blades additionally may be made featherable to govern the turbine speed by feathering the blades either preceding or after the gate openings or simultaneously as preset by the degree of biasing of both determined by matching to weather conditions in the area of use. In other embodiments, the gates are interconnected to the featherable blades for coordinated operation by means such as cables or rods.

Abstract: A measuring device (1, 12, 13, 14) is equipped with a blade angle indicator (1) indicating the blade angle adjustment of the rotor blades of a helicopter, a pressure altimeter (13) and an outside temperature probe (14). The measuring device (1, 12, 13, 14) is linked to a control device (4-6) which has a central processing unit (4) and a program memory (5). The memory (5) stores data processing instructions for determining density height from pressure height and outside temperature as well as data processing instructions corresponding to the helicopter operating instructions for determining the permissible maximum value of the blade angle from the density height. The control device (4-6) periodically determines the density height on the basis of the prevailing pressure height and outside temperature and the corresponding permissible maximum value of the blade angle.

Abstract: In one form of the present invention, turbine cooling air is modulated as a function of engine speed, altitude, and blade temperature.

Abstract: Inadvertent slot opening in a circulation controlled rotor due to plenum valve leakage is averted by venting duct pressure below a control minimum. A vent valve is disclosed.

Abstract: The disclosed system detects the pressure rise across the fan and the flow rate in the system and integrates signals corresponding thereto, and outputs a signal to indicate to the user when the pressure rise exceeds a given level for a corresponding flow rate to warn of a condition within a given degree of a stall condition. The system outputs another signal to block any increase in fan blade pitch and substitutes a decrease pitch signal in response to a predetermined closer approach to a stall condition so that the pitch of the blades is reduced to a position in which the pressure rate rise and flow rate are reduced to a safe level with respect to a stall condition. The system also includes means responsive to the predetermined closer approach to stall to prevent the user from feeding a blade pitch increase signal following a reduction in the pressure rise across the fan until the user resets a bistable device.