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Question 275-1 : The delta 3 hinge is used to allow ? [ Analysis topography ]
Blade pitch to decrease on the upwards flapping blade
Question 275-2 : In order to permit the rotor blades to rotate freely in autorotation ?
A free wheel unit is fitted between engine and rotor.
A clutch is fitted between engine and rotor inflow must equal rate of descent airflow the rate of descent must be greater than 500fpm
Question 275-3 : The purpose of the swept back tip region in some modern rotor blade designs is to ?
Improve high speed performance.
1625Reduce blade tip vortices. reduce blade tip stresses. reduce the amount of flapping up.
Question 275-4 : A conventional tail rotor has ?
Flapping hinges incorporating a delta 3 hinge together with feathering hinges.
Flapping, feathering and dragging hinges. flapping hinges incorporating a delta-3 hinge, together with feathering and dragging hinges. only a feathering hinge.
Question 275-5 : Droop restrainers on a rotor head ?
Limit the amount of blade droop when the blades are rotating at low rotor rpm.
Are only fitted to teetering head rotor systems prevent excessive blade movement in strong or gusty wind conditions limit the amount of blade droop in forward flight
Question 275-6 : An increase in the angle of attack of a rotor blade on a helicopter in forward flight will cause the ?
Separation point to move forward.
1587Stagnation point to move forward. the centre of pressure to move aft. velocity of the air over the upper surface to reduce.
Question 275-7 : In a helicopter in forward level flight the angle of attack of the blades of a main rotor will be ?
Greatest on the retreating side.
1597the angle of attack of the blades at the retrating side must be higher than the other side due to the lower speed of the relative airlfowThe same throughout the disc. greatest at the front of the disc. greatest at the rear of the disc.
Question 275-8 : To obtain minimum power required for still air hovering induced velocities should ideally ?
Be uniform over the rotor disc.
Decrease from rotor centre to tip. increase from rotor centre to tip. increase from front to rear of the rotor disc.
Question 275-9 : The pressure at the stagnation point on a rotor blade is ?
Question 275-12 : During flight an increase in main rotor torque will require ?
An increase in tail rotor pitch.
No change in tail rotor pitch. a reduction in tail rotor pitch. a reduction in tail rotor rpm.
Question 275-13 : Fenestron blades are equipped with ?
Feathering hinges only.
Fenestron examples 1624Flapping and feathering hinges. feathering and drag hinges. flapping, feathering and drag hinges.
Question 275-14 : If the coning angle of the main rotor disc is increased ?
The centre of gravity of the blade moves inboard.
The helicopter centre of gravity moves forward the helicopter centre of gravity moves aft the cg of the blade moves outboard
Question 275-15 : Phase lag of a main rotor blade is the result of ?
Inertia and aerodynamic forces.
Advance angle blade drag. drift
Question 275-16 : Cyclic stick movement ?
Alters the disc attitude.
Alters the amount of total rotor thrust. changes the coning angle. causes an equal pitch change on all blades together.
Question 275-17 : The angle of attack of a blade section is the angle between the chord line and the ?
Relative airflow.
Rotational airflow induced airflow plane of rotation
Question 275-18 : The pitch angle of a rotor blade section is ?
The angle between the chord line and the hub plane.
The angular difference between the root and tip of the blade section the angle between the tip path plane and the relative airflow the angle at which the induced flow passes over the blade section
Question 275-19 : The coning angle is the angle ?
Between the longitudinal axis of the blade and the tip path plane.
Between maximum flapping up and maximum flapping down of the blade in autorotation between the longitudinal axis of the blade and the horizon between the normal plane of rotation in forward flight and the plane of rotation in the flare
Question 275-20 : The main rotor shaft axis is ?
The axis through the main rotor shaft.
The axis of rotation of the blades the axis of the thrust the vertical
Question 275-21 : The axis of rotation of the blades is ?
The axis through the centre of the main rotor head about which the blades rotate.
The horizontal axis of a the rotor disc the resultant of lift and drag the axis coinciding with the shaft axis
Question 275-22 : The plane of rotation is perpendicular to ?
The axis of rotation and parallel to the tip path plane.
The axis of rotation vertical through the centre of the main rotor head the shaft axis the total reaction aerodynamic forces on the blades
Question 275-23 : The tip path plane is ?
The path plane described by the blade tips during rotation and perpendicular to the axis of rotation.
The path described by the blade tips during rotation and perpendicular to the plane of rotation the plane perpendicular to the shaft axis of the main rotor the path plane described by the disc in forward flight
Question 275-24 : The type of aerofoil most commonly used for helicopter rotor blades has ?
Question 275-25 : The chord line of a blade section is ?
A straight line from leading to trailing edge.
A line equidistant from the upper and lower surface of the blade a line tangential to the wing surface on the leading edge the line of the chord used to determine balance on some smaller helicopters
Question 275-26 : The coning angle of a rotor blade is determined by the blade weight and ?
The lift and the centrifugal force.
Question 275-27 : A helicopter rotor system fitted with blade flapping hinges and blade drag hinges is said to be ?
Fully articulated.
Semi-articulated teetering semi-rigid
Question 275-28 : The three basic flight controls in a helicopter are ?
Collective pitch control cyclic pitch control and yaw control.
Collective pitch control, yaw control and throttle forward and aft trim control, lateral trim control and throttle collective pitch control, cyclic control and rotor rpm control
Question 275-29 : The rotor thrust is ?
An aerodynamic force acting perpendicular to the tip path plane.
An aerodynamic force acting perpendicular to the relative airflow. an aerodynamic force acting parallel to the tip path plane. an aerodynamic force equal and opposite to the weight.
Question 275-30 : Rotor blade drag is an aerodynamic force ?
Parallel to the tip path plane.
Perpendicular to the relative airflow. independent of the air density. perpendicular to the tip path plane.
Question 275-31 : The purpose of the collective pitch control is ?
To change the pitch angle on all rotor blades collectively.
1606To change the pitch angle of each blade by the appropriate amount. to tilt the rotor plane of rotation. to adjust the power to achieve the required thrust.
Question 275-32 : Lateral control of the helicopter is obtained by ?
The cyclic pitch control.
Tail rotor pitch control aerodynamic shape of fin pedals
Question 275-33 : The function of a helicopter tail rotor is ?
To counteract the torque reaction between the revolving main rotor and the fuselage.
To increase the balance in the turn to enable less power to be delivered to the main rotor to enable more power to be delivered directly to the main rotor
Question 275-34 : Yawing in a helicopter is the term used to define a rotation ?
About the normal axis.
About the lateral axis about the longitudinal axis which is always about the vertical axis.
Question 275-35 : Viewed from above a helicopter in the hover with anti clockwise rotating blades if not corrected would tend to drift to the ?
Right with power on.
Question 275-36 : Flapping hinges are fitted to the helicopter rotor system to allow ?
For movement of the blade in the plane perpendicular to the hub plane.
For movement of the blade in the horizontal plane during the cycle of rotation the blade to move horizontally and maintain correct rotor revolutions for movement of the blade in the vertical plane to overcome flap back and inflow roll
Question 275-37 : Drag hinges are fitted to ?
Allow for blade movement in the rotor disc plane.
Allow the blade to move in the vertical plane to reduce stresses and increase lift and drag. enable the disc to be tilted in the direction of the cyclic pitch control, by flapping up on the advancing side and down on the retreating side. allow the blades to reposition to compensate for lag.
Question 275-38 : Phase lag is ?
A vertical movement of the blades to a maximum or minimum position at the point approximating 90 degrees further on in the plane of rotation from that at which force was applied.
A gyroscopic effect of the main rotor due to a cyclic pitch change and a consequent decrease in lift and drag. vertical movement of the blades due to forward movement of the helicopter and flap back. the delay in control response after an input from the cyclic due to the effect of the sloppy link.
Question 275-39 : Advance angle is an angle between the ?
Pitch link attachement on the swash plate and the longitudinal axis of the blade.
Chord line and the pitch operating arm advancing and retreating blades pitch operating arm and the swash plate
Question 275-40 : Main rotor freedom of movement is defined as ?
Feathering flapping and dragging.
Feathering and rotation of the blades on the drag hinges. feathering and dragging of the blades in the horizontal plane. dragging and independent movement of the blades in the vertical plane.
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