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Question 278-1 : The maximum speed during backwards is lower than in forward flight this is due to ? [ Analysis topography ]
The reduced control range in the rearward direction and the directional stability of the airframe
Question 278-2 : When in the hover movement of the collective lever upwards will change the pitch angle of the main rotor blades ?
By an equal amount throughout 360 of rotation.
To prevent excessive coning of the blades independently as each blade passes the helicopter longitudinal axis about the flapping hinges
Question 278-3 : In a tail rotor asymmetry of lift ?
May be reduced by allowing blade flapping.
Cannot occur since the relative airlow velocity is the same at any position cannot be reduced in any configuration and therefore has to be accepted is essential for the correct functioning of the helicopter
Question 278-4 : A helicopter having an anti clockwise rotating main rotor when seen from above with power on will have a tendency to drift ?
To the right.
To the right if the tail rotor is on the left of the aircraft and to the left if it is on the right. in neither direction because transverse forces are in balance. to the left.
Question 278-5 : In a hingeless main rotor there are ?
Feathering bearing but no dragging or flapping hinges.
Dragging and feathering hinges but no flapping hinges. flapping and feathering hinges but no dragging hinges flapping hinges but no dragging or feathering hinges
Question 278-6 : In a shrouded tail rotor fenestron the blades ?
Respond to tail rotor collective pitch control.
The control of the tail rotor thrust is achieved by collective variation of the pitch angle of the bladesthe pitch control tail rotor blades system is connected to the rudder pedalsRespond to tail rotor cyclic and collective pitch control. respond to tail rotor cyclic control. are fully articulated.
Question 278-7 : Ground resonance can be prevented from developing to a critical point if action is taken early enough by ?
Applying collective pitch control and lifting off.
Applying the rotor brake as rapidly as possible. compensating for helicopter movement with cyclic control. avoiding any control input until all vibration has ceased.
Question 278-8 : The three main features which define the maximum speed of a helicopter are ?
Compressibility limit of advancing blade retreating blade stall and design limits of cyclic control.
Runaway rotor rpm limit, critical flapback speed and airflow reversal retreating blade stall, blade sailing limit and tail rotor overspeed limit design limit of collective control, compressibility limit of advancing blades and airflow reversal
Question 278-9 : During autorotative flight ?
The fuselage will tend to rotate in the same direction as the rotor.
Yaw is controlled by the cyclic control since the low tail rotor rpm would exert insufficient force. no attempt must be made to control yaw through the pedals as the power required to drive the tail rotor would derive from the main rotor, reducing the rpm disastrously. collective and cyclic inputs work in the reverse sense to powered flight.
Question 278-10 : Blade sailing with the attendant possibility of a blade strike on the tail boom or rear fuselage is most likely to occur ?
During very low rotor rpm conditions particularly whilst starting or stopping the engine in gusty conditions.
During an autorotative descent whilst hovering in strong winds when carrying out extreme manoeuvres involving or approaching zero 'g'
Question 278-11 : The primary factor which prevents the main rotor blade coning upwards on an articulated rotor head is ?
The centrifugal force acting on the blades.
Gravity acting on the blades. the lift developed by the blades. coriolis effect.
Question 278-12 : Blades with a positive coning angle flapping upwards tend to ?
Increase rotational speed.
Decrease rotational speed. stall. increase the angle of attack.
Question 278-13 : An increase in angle of attack of a rotor blade element below the stall angle causes an increase in ?
Drag and lift forces.
Induced drag and a decrease in parasite drag but no change in lift unless rotor speed is increased. induced drag and parasite drag but a reduction in lift. lift only.
Question 278-14 : A shrouded tail rotor fenestron ?
Largely removes lift dissymmetry and the attendant need for cyclic feathering of the tail rotor.
Removes the need for tail rotor pitch control, allowing yaw control to be achieved by a fin and rudder allows the tail rotor to be used for pitch as well as yaw control permits greater cg movement fore and aft
Question 278-15 : During an autorotative descent the maximum gliding distance will be obtained at ?
A speed greater than that associated with the minimum rate of descent.
The speed associated with the minimum rate of descent a speed slightly less than that associated with the minimum rate of descent the minimum speed that will sustain rotor rpm
Question 278-16 : In forward flight the lift produced by a given blade element is dependent upon ?
Angle of attack and the square of its air speed.
Angle of attack and the square of its rotational speed pitch angle and the square of its rotational speed pitch angle and the square of the forward speed of the helicopter
Question 278-17 : When the cyclic pitch control is forward a main rotor blade will reach its maximum pitch ?
On the retreating side.
In the rear most position. on the advancing side. in the fore most position.
Question 278-18 : Blade hinges arranged with a 'delta three' hinge effect ?
Decrease their pitch angle with flap up.
Have no need to change their pitch cyclically without a pilot input. decrease their pitch angle with blade dragging. increase their pitch angle with flap up.
Question 278-19 : Some tail rotor hinges are not perpendicular to the feathering axis in order to ?
Reduce the effects of dissymmetry of lift with forward speed.
Since the tail rotor is subjected to dissymmetry of rotor thrust it is often fitted with flapping hinges normally they have delta 3 hinges that decrease the angle of attack when the blade flaps up and vice versaProvide a pitch change hinge free from phase lag cater for centrifugal twisting moment produce a stabilising lift component when lift is increased at the main rotor by an increase in rpm
Question 278-20 : The normal or yaw axis of a helicopter is a straight line ?
Passing through the centre of gravity perpendicular to the longitudinal and lateral axes.
Passing through the centre of lift perpendicular to the relative airflow coincident with the main rotor axis passing through the centre of gravity and perpendicular to the helicopter velocity
Question 278-21 : The angle of attack of an aerofoil section is the angle between the ?
Chord line and the relative airflow.
Plane of rotation and the direction of flight of the helicopter lower surface of the aerofoil and the relative airflow chord line and the horizontal
Question 278-22 : A helicopter is statically stable when it exhibits the ?
Tendency to return to its original attitude after a disturbance.
Tendency to pitch at low airspeed ability to rotate about an axis ability to accelerate in forward flight without excess fuselage pitch down
Question 278-23 : The amount of lift produced by a given helicopter rotor blade element is dependent upon ?
The angle of attack of the blade the square of the air velocity relative to the blade element and the air density.
The angle of attack of the blade, the square of the forward speed of the helicopter and the air density the pitch angle, the square of the forward speed of the helicopter and the square root of the air density the angle of attack of the blade, the square root of the relative air velocity to the blade element and the air density
Question 278-24 : Phase lag is the ?
Azimuthal angle through which a blade moves between a pitch value input and the corresponding flapped position.
Question 278-25 : As speed increases the parasite drag of a helicopter fuselage will ?
Tend to cause the nose to pitch down.
Have no effect on pitching moments tend to cause the nose to pitch up only tend to cause the helicopter to yaw in the direction of rotation of the main rotor in addition to pitch up
Question 278-26 : 'coning angle' is defined as the angle between the rotor blade's longitudinal axis and the ?
Tip path plane.
2407Rotor mast. plane containing the lateral and longitudinal axes of the helicopter. horizontal.
Question 278-27 : Disc loading is defined as the ?
Ratio of the total weight of the helicopter per unit of the disc area.
Weight of the main rotor blades maximum centrifugal loading of the main rotor hub assembly increase in rotor thrust required to compensate for accelerations during manoeuvre
Question 278-28 : In order to reduce the effects of retreating blade stall on a helicopter in flight the ?
Collective pitch should be lowered to decrease pitch.
Power should be reduced and collective pitch increased at once to reduce speed cyclic control should be pushed forward to increase speed cyclic control should be pulled back to decrease speed in a flare manoeuvre
Question 278-29 : If a helicopter is loaded for flight and the centre of gravity is within limits for take off ?
The centre of gravity position needs to be calculated for landing.
As fuel tanks are always located on the centre of gravity, the centre of gravity will not change during flight the centre of gravity may well move as fuel and oil are consumed but since the aircraft will be lighter than at take-off, the movement will not be critical for landing it is an airworthiness requirement that provided the centre of gravity is within limits on take-off, it will remain within limits for landing as fuel and oil are consumed during flight
Question 278-30 : In order to produce a stable teetering rotor it may be necessary to ?
Stabilise it by use of rotating masses.
Give it a preset coning angle embody delta-three hinges use an odd number of blades
Question 278-31 : A tilt of the rotor disc plane will cause the helicopter to accelerate ?
In the direction of tilt.
90 degrees to the direction of tilt, in the direction of rotation against the direction of tilt in the direction in which the fuselage is pointing but the pilot should rotate the fuselage against the direction of tilt in order to maintain balanced flight
Question 278-32 : The avoid areas in a 'height velocity diagram' define the heightvelocity combination ?
From which safe autorotative descent and landing after engine failure may not easily be accomplished.
From which it is not possible to operate the helicopter due to the engine being power limited from which a safe climb-out may not be made, having regard to obstacle clearance in which it is possible only to make forward (as opposed to sideways or rearwards) translational flight
Question 278-33 : In a hingeless rotor head flapping movements ?
Are accommodated for by the rotor blades flexible attachements to the hub.
Do not arise since the fuselage always follows the rotor head. are accommodated for by the whole rotor hub tilting. are accommodated by flapping hinges.
Question 278-34 : When a cyclic control input has been made the rotor blade pitch will be ?
Increasing for one half revolution and decreasing for the next half.
Increasing for one whole revolution and decreasing the next increasing or decreasing immediately and remaining at the new position until a new control input is made increasing for one quarter revolution, remaining constant for a quarter, decreasing for a quarter and then remaining constant for the last quarter
Question 278-35 : What effect does an increase in density altitude have on the amount of anti torque pedal required to maintain heading in the hover and why ?
Increased because power required increases and the tail rotor is less effective.
Decreased because the tail rotor is more effective maintained in the same position because density will affect the main and tail rotors equally decreased due to less power being required to drive the main rotor
Question 278-36 : If the centre of gravity is at the rear limit ?
Then forward cyclic travel is reduced.
Then rearward cyclic travel is reduced. then forward cyclic travel is increased. then rearward cyclic travel is not affected.
Question 278-37 : With a centre of gravity position near the front limit what will be the effect upon fuselage attitude and cyclic stick position in a still air hover ?
Nose down cyclic stick back.
2411Nose up, cyclic stick back. with the cg within limits there would be no change. nose down, cyclic stick forward.
Question 278-38 : The principal forces acting on a helicopter in forward flight are ?
Main rotor thrust weight parasite drag and main rotor profile drag.
Main rotor thrust, lift and parasite drag. main rotor thrust, weight and main rotor profile drag. lift and weight.
Question 278-39 : A nose down pitch attitude in forward flight is caused by ?
The horizontal component of total rotor thrust acting above parasite drag.
Drag acting above the thrust. lift acting forward of weight. the vertical component of total rotor thrust acting forward of the weight.
Question 278-40 : To increase forward speed in straight and level flight ?
Total rotor thrust must be increased.
Total rotor thrust must be reduced as translational lift is achieved. total rotor thrust must be reduced initially, then increased. total rotor thrust remains constant.
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