Back to results
US 5,997,250 AGranted
Method and apparatus for controlling pitch of an aircraft propeller
AssigneeCatercopters, LLC
InventorsJay Carter, Jr., Adrian P. K. Nye
Life of this patent
Estimating the term…
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.
Claims30
An improved propulsion apparatus for use on an aircraft during flight, comprising:
- (a) a propeller;
- (b) a drive system for rotating the propeller;
- (c) a pitch control system mechanically coupled to the propeller for adjusting pitch of the propeller;
- (d) at least one flight attribute sensor carried by the aircraft for monitoring one of the following flight attributes during flight and generating an output signal corresponding thereto:
- (1) drive system output power;
- (2) propeller rotation rate;
- (3) aircraft true forward flight speed;
- and
- (4) temperature;
- (e) a controller which is communicatively coupled to the flight attribute sensor for:
- (1) receiving the output signal of the flight attribute sensor;
- (2) calculating an optimum propeller rotation rate for current values of the output signal of the flight attribute sensor based upon the ratio of a true resultant propeller tip speed to a speed of sound at a given air temperature;
- (3) supplying at least one control signal to the pitch control system to adjust propeller pitch to obtain the optimum propeller rotation rate.
10 more elements
A method of controlling an aircraft propeller having a tip, comprising the method steps of:
- (a) providing at least one flight attribute sensor in said aircraft;
- (b) providing a controller for receiving data from said at least one flight attribute sensor and for performing calculations;
- (c) utilizing said at least one flight attribute sensor and said controller to calculate forward air speed of said aircraft and aircraft propeller speed;
- (d) utilizing said controller to calculate an optimum aircraft propeller rotation rate based upon true speed of the tip of said aircraft propeller as determined from said aircraft forward air speed and said aircraft propeller speed;
- and
- (e) adjusting said aircraft propeller to obtain said optimum aircraft propeller rotation rate.
3 more elements
An aircraft propeller pitch controller comprising:
- a sensor producing a first electric signal indicative of a quantity selected from the group consisting of fuel flow rate and engine output torque;
- a sensor producing a second electric signal indicative of a quantity selected from the group consisting of engine rotation rate and propeller rotation rate;
- a sensor producing a third electric signal suggestive of indicated forward flight speed;
- a sensor producing a fourth electric signal indicative of a quantity selected from the group consisting of static atmospheric pressure and altitude;
- a sensor producing a fifth electric signal indicative of atmospheric temperature;
- means responsive to said first, second, third, fourth, and fifth electric signals for calculating an optimum rotation rate such that the vector sum of aircraft true forward airspeed and propeller rotational tip speed is a selected fraction of the speed of sound;
- and
- means for controlling a propeller blade pitch such that the rotation rate becomes substantially equal to said optimum rotation rate.
5 more elements
An aircraft propeller pitch controller comprising:
- a sensor producing a first electric signal indicative of a quantity selected from the group consisting of fuel flow rate and engine output torque;
- a sensor producing a second electric signal indicative of a quantity selected from the group consisting of engine rotation rate and propeller rotation rate;
- a sensor producing a third electric signal suggestive of true forward flight speed;
- a sensor producing a fourth electric signal indicative of atmospheric temperature;
- means responsive to said first, second, third, and fourth electric signals for calculating an optimum rotation rate such that the vector sum of aircraft true forward airspeed and propeller rotational tip speed is a selected fraction of the speed of sound;
- and
- means for controlling a propeller blade pitch such that the rotation rate becomes substantially equal to said optimum rotation rate.
4 more elements
An aircraft propeller pitch controller comprising:
- a sensor producing a first electric signal indicative of true forward flight speed;
- a sensor producing a second electric signal indicative of a quantity selected from the group consisting of fuel flow rate and engine output torque;
- a sensor producing a third electric signal indicative of a quantity selected from the group consisting of engine rotation rate and propeller rotation rate;
- means responsive to said first, second, and third electric signals for calculating an optimum rotation rate such that the vector sum of aircraft true forward airspeed and propeller rotational tip speed is a selected fraction of the speed of sound;
- and
- means for controlling a propeller blade pitch such that the rotation rate becomes substantially equal to said calculated optimum rotation rate.
3 more elements
Dependencies are inferred from the claim text.