Method and device for determining aerodynamic characteristics of an aircraft

• US 8,442,705 B2
• Filed: 02/12/2010
• Issued: 05/14/2013
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Airbus Operations GmbH (Airbus SE)
• Original Assignee: Airbus Operations GmbH (Airbus SE)
• Inventors: Giesseler, Hans-Gerd, Stegelmeier, Wilfried, Tauzin, Chlo
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Lewandroski, Sara
• Application Number:
  US12/704,661
• Publication Number:
  US 20100222945A1
• Time in Patent Office: 1,187 Days
• Field of Search: 701/3, 701/14, 703/2
• US Class Current: 701/14
• CPC Class Codes: G01M 9/06 Measuring arrangements specially adapted for aerodynamic testing

Abstract

The present invention provides a device and method for determining aerodynamic characteristics of an aircraft, in particular a pitch moment coefficient at an ascending force of the aircraft without a horizontal tail plane of zero and an aerodynamic neutral point of the aircraft without a horizontal tail plane. In the method according to the invention, forces and mechanical flight parameters on aerofoils and a horizontal tail plane of the aircraft are detected at various detection instants during at least one non-stationary flight maneuvre of the aircraft. In this case, a linear system of equations is formed, which comprises a pitch movement moment balance equation for each detection instant, the pitch movement moment balance equation having the detected forces and mechanical flight parameters. This linear system of equations is evaluated to calculate the aerodynamic characteristics.

Claims

1. A method for determining aerodynamic characteristics of an aircraft:

(a) detecting forces and mechanical flight parameters by sensors on aerofoils and a horizontal tail plane of the aircraft at various detection instants during at least one non-stationary flight manoeuvre of the aircraft; and

(b) evaluation of a system of equations by a calculation unit, the system comprising, for each detection instant, a pitch movement moment balance equation, which has the detected forces and mechanical flight parameters, to calculate the aerodynamic characteristics of the aircraft;

wherein a spindle force in a trimming spindle of the horizontal tail plane and bearing forces in a left and right rotary bearing of the horizontal tail plane are detected by sensors during the flight manoeuvre; and

wherein a vertical ascending force F_z^wfP of the aircraft without a horizontal tail plane is calculated as a function of the spindle forces and bearing forces of the horizontal tail plane detected by the sensors and of detected or derived vertical load factors by the following vertical load factor equation;

2. The method according to claim 1, wherein by evaluating the system of equations, a pitch moment coefficient at an ascending force of the aircraft without a horizontal tail plane of zero and an aerodynamic neutral point of the aircraft without a horizontal tail plane are determined as the aerodynamic characteristics.

3. The method according to claim 1, wherein the evaluation of the system of equations on the basis of forces and mechanical flight parameters recorded during the flight manoeuvre takes place at a later instant or in real time.

4. The method according to claim 1, wherein the system of equations is formed by a linear system of equations, which is solved by an overdetermined numerical optimisation method.

5. The method according to claim 1, wherein the flight manoeuvre is primarily a longitudinal movement manoeuvre of the aircraft.

6. The method according to claim 1, wherein the pitch movement moment balance equation has the vertical ascending force F_z^wfp of the aircraft calculated by the vertical load factor equation, without a horizontal tail plane:

7. The method according to claim 1, wherein a vertical load factor at the centre of gravity of the aircraft, a vertical load factor at a centre of gravity of a trimming tank and a vertical load factor at a centre of gravity of the horizontal tail plane are detected by sensors during the flight manoeuvre or derived from sensor data.

8. The method according to claim 6, wherein the system of equations is an overdetermined linear system of equations and wherein the overdetermined linear system formed from pitch movement moment balance equations form detection instants:

9. A non-transitory programme with programme commands for carrying out the method according to claim 1.

10. A non-transitory data carrier which stores the programme according to claim 9.

11. A device for determining aerodynamic characteristics of an aircraft comprising:

(a) Sensors for detecting forces and mechanical flight parameters on aerofoils and a horizontal tail plane of the aircraft at various detection instants during at least one non-stationary flight manoeuvre of the aircraft; and

comprising

(b) A calculation unit to evaluate a system of equations, which for each detection instant comprises a pitch movement moment balance equation, which has the detected forces and mechanical flight parameters to calculate the aerodynamic characteristics of the aircraft

wherein a spindle force in a trimming spindle of the horizontal tail plane and bearing forces in a left and right rotary bearing of the horizontal tail plane are detected by sensors during the flight manoeuvre; and

wherein a vertical ascending force F_z^wfp of the aircraft without a horizontal tail plane is calculated as a function of the spindle forces and bearing forces of the horizontal tail plane detected by the sensors and of detected or derived vertical load factors by the following vertical load factor equation;

12. The device according to claim 11, wherein the device is mounted on the aircraft.

13. The device according to claim 11, wherein the sensors are mounted on the aircraft and transmit the detected forces and mechanical flight parameters via a radio interface to a base station having the calculation unit.