An Integrated, Modular Simulation System for Education ... - Cal Poly

6 DOF Model VerificationThe 6 DOF model used a L-17 Navion piston engine, propellerdriven light Air Force liason aircraftshown in Figure 19. for validation.The aircraft was used to demonstrateFigure 19 L-17 Navionstability analysis calculations in [Ref. 33] Using the state space model, as well as inputfrom undergraduate students testing the FASAND program, several errors were found inthe first edition of the text book that were providing dynamics that were inconsistent withan aircraft of the type modeled in the text. The roll control derivative was off by twoorders of magnitude causing a roll time constant of 17 seconds rather than 0.15 sec. Theyaw-roll (Clδr) coupling was off by an order of magnitude causing a severe dutch roll.The sign for aileron control (Clδa) was reversed. The results produced reversed rollresponses in the state space and 6 DOF models. Since the FASAND code runs as a batchat close to actual time using fairly large time steps the initial verification consisted ofchecking various dynamics by hand calculating time constants and damping ratios usingthe published characteristics.To have a complete baseline set of dynamics, the stability derivatives wereentered into the program Archangel. The program dimensionalizes the non-dimensionalderivatives, given a set of initial conditions, then combines and arranges the derivativesinto two state space systems for the longitudinal and lateral directions. A second statespace was set up using dervatives published in [Ref. 33]. The two state spaces matched inmost places however there were a couple of places that the dynamics differed. The Statespaces were used to create flying models for the PhEagle lab and to set up as Linearly60