Patent ID: 8442705

Claim:
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: - mgn z cg = F z wfp + 1 co ⁡ [ F z screw + F z attach ⁢ ⁢ L + R - m HTP ⁢ gn z HTP - m TT ⁢ gn z TT ] wherein co is a predetermined carry over factor, g is the gravitational constant, m is the mass of the aircraft, m HTP is the mass of the horizontal tail plane, m TT is the mass of the trimming tank, n z cg is the vertical load factor at the centre of gravity of the aircraft, n z HTP is the vertical load factor at the centre of gravity of the horizontal tail plane, n z TT is the vertical load factor at the centre of gravity of the trimming tank, F z screw is the spindle force in the trimming spindle of the horizontal tail plane, F z attach L+R is the bearing forces in a left and right rotary bearing of the horizontal tail plane.