Development of a low-cost and versatile flight test platform

This paper describes the creation of an independent flight test facility in Portugal, based on international and national cooperation; the flying element is the basic aircraft for night research (BAFR), a CASA 212 Aviocar twin-turboprop light transport, fitted with a flight test instrumentation (FTI) system, from which smaller dedicated FTIs were developed for several other aircraft. A part of one of the research projects carried out with BAFR, viz., a linear longitudinal stability model, including propeller slipstream effects is described. The model is reduced from 3 x 5 form to a 4 x 4 autonomous system of differential equations, from which the frequency and damping of the phugoid and short period modes are determined. The model parameters were identified from night tests of selected maneuvers and the reconstruction of flight data using the model served to validate the latter.