Flight Test Planning and Data Extraction
Author: Stefan Velikov
Thesis
Abstract
A dynamically scaled model of a business jet design, the Raven, has been built at the
Linköping University to investigate the possibilities of flight testing with subscale radio
controlled aircraft models within a low-budget university project. This work comprises a
theoretical approach of flight test planning and post-flight data handling to identify the
aircraft’s aerodynamic performance and dynamic behaviour. Calibration methods for pressure
sensors are also presented with an emphasis on in-flight test procedures to determine position
error and their corresponding data reduction. For drag predictions a basic thrust model of
Raven’s engines is included, which consists of linear scaling of available thrust data. Its
accuracy is however questionable and is to be further verified. Since determination of
aerodynamic performance has high priority during the first tests, main part of this work deals
with flight test procedures to determine lift and drag coefficients as a function of angle of
attack from a steady level flight and series of steady glides. The corresponding data reduction
sequences are adjusted in accordance with the available instrumentation of the Raven. In
addition, techniques to investigate aircraft longitudinal and lateral-directional static stability
from flight testing are presented with data reduction methods to identify important parameters
like neutral point position, pitching moment coefficient and side-force stability derivatives.
Furthermore, flight test methods to determine characteristic dynamic stability parameters like
damping ratio and frequency for the individual modes of motion are given. This includes
various piloting techniques and post-flight results evaluation.