Ground effects compensated angle of attack command system and method
View Patent ↗A take off ground effects compensated angle of attack system includes a radio altimeter and/or timer, a pitch angle system and a flight control computer. The radio altimeter generates a signal which is indicative of the aircraft's altitude from 0 i.e., weight off wheels to an altitude of ½ the wing span of the aircraft. The angle of attack system simultaneously generates a signal which is indicative of the aircraft's angle of attack without compensation for ground effects. Therefore, a ground effects signal of from 1½° to 0° is generated and added to the angle of attack signal as the aircraft climbs from 0 ft. to an altitude which is equal to ½ the wing span of the aircraft. The ground effects signal is added to the angle of attack signal to provide a ground effects compensated angle of attacks signal which is then fed to the flight control computer or display.
1. A ground effects compensation system for generating a compensated angle of attack signal during a takeoff of an aircraft, said system comprising a flight control system, an altimeter and means for indicating the angle of attack of an aircraft and for generating a signal indicative of the aircrafts angle of attack;
means including said altimeter for generating a signal indicative of the aircrafts altitude upon achieving the weight off wheels and until said aircraft reaches an altitude equal to about ½ of the wing span of the aircraft;
means for generating a linear proportional ground effects compensation signal of between 1½° to 0° as the aircraft climbs from the weight off wheels to an altitude which is equal to about ½ the wing span of the aircraft; and
means for combining the signal indicative of the aircraft's angle of attack and the linear proportional ground effects compensation signal to thereby provide a ground effects compensated angle of attack signal.
2. A ground effects compensation system for generating a compensated angle of attacks signal during a takeoff of an aircraft according to claim 1 which includes sensing means for sensing the weight off wheels of an aircraft as the aircraft leaves the ground and for generating a signal indicative of the weight off wheels.
3. A ground effects compensation system for generating a compensated angle of attacks signal during a takeoff of an aircraft according to claim 1 which includes means for inputting said ground effects compensated angle of attack signal into said flight control computer.
4. A ground effects compensation system for generating a compensated angle of attacks signal during a takeoff of an aircraft according to claim 3 in which said altimeter is a radio altimeter.
5. A ground effects compensation system for generating a compensated angle of attacks signal during a takeoff of an aircraft according to claim 1 in which said means for indicating the aircraft's angle of attack includes an angle of attack vane.
6. A method for generating a ground effects compensated angle of attacks signal during a takeoff of an aircraft comprising the steps of:
providing a radio altimeter and an angle of attack vane for generating signals indicative of an aircraft's altitude and angle of attack at indicated altitudes from weight off wheels to an altitude of about ½ the wing span of the aircraft;
generating a linear proportional ground effects compensation signal of between 1½° to 0° as the aircraft climbs from the weight off wheels to an altitude which is equal to about ½ the wing span of the aircraft; and
adding the linear proportional ground effects compensation signal to the angle of attack signal for altitudes between weight off wheels and an altitude which is equal to about ½ the wing span of the aircraft.
7. A method for generating a ground effects compensated angle of attacks signal during a takeoff of an aircraft comprising the steps of:
providing a radio altimeter and an angle of attack vane for generating signals indicative of an aircraft's altitude and angle of attack;
sensing the weight off wheels during the takeoff of the aircraft;
generating a signal indicative of the aircraft's altitude and angle of attack at indicated altitudes between weight off wheels and an altitude of about ½ the wing span of the aircraft;
generating a ground effects compensation signal representative of ground effects between weight off wheels and an altitude which is equal to about ½ the wing span of the aircraft; and
combining the signals indicative of the aircraft's angle of attack and the ground effects compensation signal to thereby provide a ground effect compensated angle of attack system.
8. A method for generating a ground effects compensated angle of attack signal during a takeoff of an aircraft in accordance with claim 7 which includes the step of providing a flight control system and inputting the ground effects compensated angle of attack signal into the flight control system.