RAPIT – A Tool For Monitoring Aircraft Stability And Control

Christian Raab, DLR, Institute of Flight Systems, Braunschweig, Germany

Abstract

Determination of aerodynamic derivatives giving direct physical insight into the aircraft stability and control characteristics has been of interest for flight test for a long time. Normally these aerodynamic derivatives are calculated using parameter estimation algorithms after the flight. Today’s data acquisition technology allows calculation of aerodynamic parameters onboard the aircraft in near real-time.

This paper introduces a software tool called RAPIT (Rapid Aerodynamic Parameter Identification Tool), which processes the acquired flight data, calculates the aerodynamic derivatives and displays information about the aircraft’s stability and control characteristics on the flight test engineer’s screen. Different displays showing the current flight data and the estimation results can be selected by the user.

RAPIT was installed onboard the DLR research aircraft A320-ATRA and an EMBRAER Phenom 300 test aircraft. Flight campaigns were conducted with typical excitation maneuvers. RAPIT was used to monitor the maneuvers and to estimate aerodynamic parameters online. Results from two maneuvers will be presented and discussed in this paper.