Spring 2003 16.61AC3-7 Aircraft Actuator Influence Transfer functions dominated by lightly damped Dutch-roll mode Note the rudder is physically quite high, so it also influences the A/C Ailerons influence the Yaw because of the differential drag e Impulse response for the two inputs. Rudder input ◇β shows a very lightly damped deca o p, r clearly excited as well ◇ o oscillates around2.5° Dutch-roll oscillations are clear Spiral mode ultimately dominates -0 after 250 sec Aileron input ◇ Large impact on p o Causes large change to o o Very small change to remaining variables o Influence smaller than rudder Lateral approximate models are much harder to make(see discussion in Etkin and Reid). Not worth discussing at lengthSpring 2003 16.61 AC 3–7 Aircraft Actuator Influence • Transfer functions dominated by lightly damped Dutch-roll mode. – Note the rudder is physically quite high, so it also influences the A/C roll. – Ailerons influence the Yaw because of the differential drag • Impulse response for the two inputs: – Rudder input ✸ β shows a very lightly damped decay. ✸ p, r clearly excited as well. ✸ φ oscillates around 2.5◦ ⇒ Dutch-roll oscillations are clear. ⇒ Spiral mode ultimately dominates φ → 0 after 250 sec. – Aileron input ✸ Large impact on p ✸ Causes large change to φ ✸ Very small change to remaining variables. ✸ Influence smaller than Rudder. • Lateral approximate models are much harder to make (see discussion in Etkin and Reid). Not worth discussing at length. 7