Welcome to AE Resources
DYNAMICS PROBLEMS
For each wheel, friction force is f and there are 16 wheels. Force balance on the entire aircraft leads to the following equation
(1) F − 16f = Ma
  1. (2) fr = Iα = I(a)/(r)
     ⇒ f = (Ia)/(r2)
     ⇒ F − (16Ia)/(r2) = Ma
    Thus, initial linear acceleration of the aircraft is given by
    (3) a = (F)/(M + (16I)/(r2))
  2. figure images/LandingGear.PNG
    Figure 3 Figure depicting the free body diagram of the landing gear.
    figure images/Wheel1.PNG
    Figure 4 Figure depicting the phase before pure rolling.
    figure images/Wheel2.PNG
    Figure 5 Figure depicting pure rolling motion.
    figure images/Wheel4.PNG
    Figure 6 Figure depicting rolling motion with brakes applied.
    1. Just after the touchdown, the translational velocity of the wheels is more than that of the rolling velocity. Thus the wheels slip (Vl > ωr). This phase is depicted in Figure 4.
    2. In the rolling phase, when the wheels are undergoing pure rolling motion, the velocity of the wheels is given by Vl = ωr. The angular velocity ω of the wheels is constant in this phase, since there is no frictional force acting to reduce it. This phase of pure rolling is depicted in Figure 5.
    3. When the brakes have been applied, the velocity of the wheels is still given by Vl = ωr. However the wheels undergo deceleration due to the applied torque and thus the angular velocity of the wheels (ω) is not a constant. The maximum frictional force acting is limited by the coefficient of static friction. The braking phase is depicted in Figure 6.
Next Page →
Next Page →
← Previous Page
← Previous Page