Untersuchung flugmechanischer Eigenschaften mit Methoden der Ähnlichkeit

  • Investigation of flightmechanical characteristics with similarity methods

Hahnen, Georg; Alles, Wolfgang (Thesis advisor); Moormann, Dieter (Thesis advisor)

Aachen (2017)
Dissertation / PhD Thesis

Dissertation, RWTH Aachen University, 2017


Information about the flightmechanical characteristics of a new airplane is necessary from design through development until certification.Free-flight tests with dynamically similar scaled models can provide a useful contribution in all stages.In addition to geometric scaling, dynamic similarity requires the same relative airplane mass density and Froude number of the scaled free flight model and the unscaled airplane.This thesis demonstrates that the method of dynamically scaled free flight models can in particular be applied to general aviation airplanes and their certification according to CS-23.To this end, the requirements of dynamic scaling were investigated with respect to the applicability to models with different weights.It could be shown that free flight models with a maximum weight of 25 kg are particularly useful to build dynamically scaled models of general aviation airplanes.Within the scope of the European research project CESAR a dynamically scaled model of the EV-55 Outback was designed and built.Flight test maneuvers were chosen from maneuvers which are also used during the certification process according CS-23.A parameter identification of the model was executed based on the output error method.The parameter identification results of the model were converted to the unscaled airplane and an evaluation of the flightmechanical characteristics was performed with respect to the CS-23 certification requirements.The result of this work is that dynamically scaled free flight models are very useful to investigate CS-23 certification requirements on static and dynamic stability as well as some flight performances. Even though for some parameters the flight test maneuvers could not excite the proper motion of the model for an estimation of all parameters.For other very generally described requirements more informations are required to evaluate the requirements. Without a comparison to an already certified airplane and its dynamically scaled model an evaluation is only possible with limitations.