Exam examples

Page 1

Sample exam paper 1  Define and describe coordinate frames used for flight dynamics work.  Summarise the main conclusions of static stability analysis in pitch for a conventional aircraft.  Lateral-directional dynamics: define the state variables for the lateral-directional model and describe the corresponding modes, in terms of eigenvalue location, shape and duration of time response, state contribution.  For an aircraft with transfer function from elevator to pitch rate given by 𝐺ఋொ ೐(𝑠)= 0.98(𝑠+ 0.56)(𝑠+ 0.04) (𝑠ଶ + 1.16𝑠+ 1.19)(𝑠ଶ + 0.014𝑠+ 0.014) compute natural frequencies and damping ratios for the short period and phugoid modes and draw qualitative Bode plots of magnitude and phase of the frequency response function. Magnitude (dB) Phase (deg) Sample exam paper 2  Discuss the most common parameterisations for rigid body attitude and motivate the choice usually made for flight dynamics work.  Describe the assumptions under which the aircraft model can be decoupled into longitudinal and lateral-directional dynamics.  Longitudinal dynamics: define the state variables for the longitudinal model and describe the corresponding modes, in terms of eigenvalue location, shape and duration of time response, state contribution.  For a pitch control loop given by 𝐺ఋொ ೐(𝑠)= ଴.ଽ଼(௦ା଴.ହ଺) (௦మାଵ.ଵହ௦ାଵ.ଵ଼), KQ=0.528, Kp=1.5, Ki=3, with the Bode plots for the loop transfer function depicted in the figure compute 𝜔௖ and 𝜑௠ , assess the steady state error for a step change in 𝛿𝑄௢ and evaluate the gain margin. Magnitude (dB) Phase (deg)