直升机飞行力学复习题.doc

Chapter OneA helicopter of central articulated rotor makes a level flight with cruse speed. In this flight condition, the pitching attitude angle is , longitudinal cyclic pitching angle is, rotor longitudinal flapping angle is . Assuming the tilted angle of rotor shaft is, please determining the following angles:Helicopter climb angle Fuselage attack angle Rotor attack angle Rotor flapping due to forward speed Chapter Two1. For the main/tail rotor configuration helicopter, the pilot applies which stick or rudder to control what kind of surfaces and corresponding aerodynamic forces? 2. Why the gradient of control stick forces cant be too large or small?3. Co-axis, tandem and tilted-rotor helicopters have no tail rotor. How to change the direction in hover for these helicopters?Chapter Three1. The rotation direction of Black hawk helicopter rotor is anticlockwise from the top view. Please answer the following questions: l How the rotor flaps when the helicopter comes up gust in hover? How to adjust the controller to keep the hover condition?l How the blade changes its feathering angle following the pilots adjustment? 2. During left and right turn flights with constant speed and altitude, is there any different for pilot controls? 3. Is there flapping motion for hinge-less rotor? Chapter FourWhich items in the linear equations of helicopter motion reflect the longitudinal and lateral cross-coupling effect?Chapter Five1. What is the mission of helicopter trim calculation?2. In order to keep the center of helicopter mass in the specified range it is necessary to check the helicopter loadings before flight. Why the center of helicopter mass must be in the specified range? 3. The tail rotor of some helicopters is lower than main rotor. What is the advantages and disadvantages when the tail rotor is lower than main rotor?4. Bell-412 helicopter releases left and right buoys for making an urgent lading on the water surface. Compare the differences of pilot controls and helicopter attitude before and after releasing buoys.Chapter Six1. The feathering angle of horizontal tail is negative. Analysis the speed stability and pitch damping if the feathering angle of horizontal tail is positive.2. Analysis the effect of flapping hinge offset on the speed stability, attack angle stability, diheadral effect and yaw stability.3. What is the different of longitudinal hover oscillation from lateral hover oscillation? 4. Why co-axis helicopter always uses two vertical tails?Chapter Seven1. What is the physical meaning of helicopter control bandwidth?2. Analysis the effects of following factors on the damping, control sensitivity and time constant of helicopter vertical motion. l Increasing rotor solidityl Increasing rotor rotational speed3. There is no oscillation for the response of helicopter to collective pitch control, while the responses of helicopter to stick or rudder are oscillation. Why? Chapter Eight1. How many methods of assessing the helicopter handling qualiti