Exam quiz Principles of Flight (Helicopter) - PPL(H) - Private Pilot License

Question 1

During an autorotation with forward speed of a helicopter the driving forces are located in the...

Accepted Answer

Region of the retreating rotor blade.

Answer

Inner region.

Answer

Outer region.

Answer

Region of the advancing rotor blade.

Question 2

What is the reason for retreating blade stall?

Accepted Answer

Large pitch angle and small effective airflow

Answer

Large centrifugal forces of the peripheral speed

Answer

Small cone angle and constant peripheral speed

Answer

Small pitch angle and large effective airflow

Question 3

The helicopter's stability is increased by...

Accepted Answer

Attaching a stabilizer.

Answer

Reducing the rotor RPM.

Answer

Pivoting the drag hinge.

Answer

Decreasing the rotor mass.

Question 4

What happens to thrust and tangential force if the rotor RPM decreases by about 10 % in cruise flight?

Accepted Answer

The thrust and the tangential force decrease

Answer

The thrust and the tangential force increase

Answer

The thrust decreases and the tangential force remains constant

Answer

The thrust remains constant and the tangential force increases

Question 5

If the critical angle of attack is exceeded, the...

Accepted Answer

Boundary layer on the upper side of the rotor blade begins to separate.

Answer

Transition point starts moving towards the airflow direction.

Answer

Boundary layer on the lower side of the rotor blade begins to separate.

Answer

Laminar boundary layer turns into a turbulent boundary layer.

Question 6

Which of the stated relationships between lift and drag applies best for a flying helicopter (lift : drag)?

Accepted Answer

45 : 1

Answer

1 : 45

Answer

1 : 2

Answer

2 : 1

Question 7

What is caused by an increase of stability in a helicopter?

Accepted Answer

A relief of the pilot in command

Answer

A decrease of the required control forces

Answer

An enhance of control under all load factors

Answer

An optimization of the maximum helicopter mass

Question 8

The rotor thrust is...

Accepted Answer

Perpendicular to the tip path plane.

Answer

Opposite to the rotation of the rotor blade element

Answer

Parallel with the main rotor shaft.

Answer

Perpendicular to the hub plane.

Question 9

The drive system of the autogyro's main rotor is based on...

Accepted Answer

The speed of the airflow.

Answer

A fan in the cabin.

Answer

An engine in the cabin.

Answer

An engine at the rotor blade tip

Question 10

What is the risk arising in a vertical autorotation with a subsequent increase in airspeed prior to the landing?

Accepted Answer

Misjudgement when increasing the airspeed

Answer

High rotor RPM

Answer

Vortex ring state

Answer

Loss of the tail rotor efficiency

Question 11

What is caused by an increase of stability in a helicopter?

Accepted Answer

An increase of general flight safety

Answer

An optimization of the maximum helicopter mass

Answer

An enhance of control under negative load factors

Answer

A decrease of the required control forces

Question 12

The virtual rotation axis of a rotor is...

Accepted Answer

Perpendicular to the tip path plane.

Answer

Perpendicular to the hub plane.

Answer

Parallel with the main rotor shaft.

Answer

Perpendicular to the plane which contains the swash plate.

Question 13

Why is a helicopter's climb initially accelerated after an increase of the pitch angle?

Accepted Answer

The inertia of the air increases the effective angle of attack temporarily until an additional component of the climb rate reduces the effective angle of attack again

Answer

The larger pitch angle causes a decrease and a compression of the airflow until the climb rate corresponds to the induced velocity through the main rotor disc

Answer

The initially high airflow increases the rotor thrust until the lower air density reduces the rotor thrust again

Answer

The conversion of energetic air into kinetic rotor energy decreases continuously with increasing density altitude

Question 14

After entering an autorotation a large helicopter mass leads to...

Accepted Answer

A rapid build-up of the rotor RPM.

Answer

A rapid collapse of the rotor RPM.

Answer

A large change in center of gravity.

Answer

A small rate of descent in a vertical autorotation.

Question 15

The rotor RPM is kept constant in the helicopter by the engine RPM. It can be influenced by the...

Accepted Answer

Throttle and the governor.

Answer

Cyclic stick.

Answer

Starter and the impulse coupling.

Answer

Collective.

Question 16

What force affects the braking torque of the rotor in cruise?

Accepted Answer

Inclined rearward tangential force

Answer

Inclined forward lift

Answer

Upward directional rotor thrust

Answer

Inclined forward drag force

Question 17

The effective airflow velocity of a rotor blade element varies with the distance from the rotor shaft axis, because the...

Accepted Answer

Peripheral speed increases if the displacement to the rotor blade tip decreases-

Answer

Helicopter airframe disturbs the airflow.

Answer

Tangential force and airflow reversal vary.

Answer

Drag force in direction of the rotaion axis is increased.

Question 18

What needs to be observed in conjunction with a temporary loss of tail rotor efficiency in a stationary hover?

Accepted Answer

Vortex ring stage of the tail rotor

Answer

Rotating movement in the main rotor direction

Answer

Loss of the main rotor thrust

Answer

Mechanical blockage of the control

Question 19

What action is necessary in a modern helicopter during the transition to a horizontal turn?

Accepted Answer

A control column movement backward or raising the collective

Answer

A control column movement forward or raising the collective

Answer

Open the throttle in a helicopter with a rotor turning in an anti-clockwise direction seen from above

Answer

Open the throttle in a helicopter with a rotor turning in a clockwise direction seen from above

Question 20

Why does a flare during an autorotation generate higher rotor RPM?

Accepted Answer

The vertical airflow through the rotor disc increases

Answer

The pitch angle increases

Answer

The tangential force tilts backwards

Answer

The ground effect leads to better performance

Question 21

Which of the following options has an effect on the autorotation characteristics?

Accepted Answer

Helicopter mass and density altitude

Answer

Smoothly working tail rotor control and low RPM warning systems

Answer

Air temperature and wind speed

Answer

Pressure altitude and wind speed

Question 22

What behavior does a helicopter without stabilization systems show after external disturbances in a hover, without a corrective action?

Accepted Answer

Statically stable and dynamically instable

Answer

Statically stable and dynamically stable

Answer

Statically indifferent and dynamically instable

Answer

Statically stable and dynamically indifferent

Question 23

What causes the phase lag between the displacement and the flapping of a rotor blade?

Accepted Answer

Inertia, mass, and aerodynamic forces

Answer

Rounding of the rotor blade tips

Answer

Friction in the rotor blade spindles

Answer

Advance or retreat angle of 90°

Question 24

Which statement about the rotor disc loading in a horizontal curve is correct?

Accepted Answer

It increases with increasing bank angle

Answer

It decreases with increasing bank angle

Answer

No change in relation to the cruise flight

Answer

Effects depend on the type of helicopter

Question 25

Which statement about the required force to change the pitch angle is correct?

Accepted Answer

It must be greater than the tangential force

Answer

It is the smallest by using an advance angle of 90°

Answer

It is the smallest by using a delta-three-hinge

Answer

It must be greater than the rotor disc loading

Question 26

During hover flight, the induced airflow velocity...

Accepted Answer

Increases further having passed the rotor.

Answer

Is equal above and below the rotor.

Answer

Remains constant after having passed the rotor.

Answer

Decreases after having passed the rotor.

Question 27

Why are the stability criteria of a helicopter very important?

Accepted Answer

A lack of stability may lead to loss of control

Answer

Low stability reduces the available control forces

Answer

High stability prevents low load factors

Answer

Large stability increases the maximum take-off mass

Question 28

The neutral point is a point where...

Accepted Answer

The torque at the chord line remains constant for changing angles of attack.

Answer

The aerodynamic forces act torque-free.

Answer

The imaginary axes of a helicopter meet each other

Answer

The entire helicopter mass can be assumed to attack.

Question 29

Which landing site (no wind) prevents the impairment of the ground effect?

Accepted Answer

Plain terrain

Answer

Narrow forest glade

Answer

Elevated helipad

Answer

Sloping ground

Question 30

What action has no effect on the rotor RPM in an autorotation?

Accepted Answer

Utilisation of friction brake.

Answer

Centre of gravity displacement.

Answer

Pitch angle change.

Answer

Transition into a turning flight.

Question 31

During an autorotation the airspeed is limited by...

Accepted Answer

The drift of the driving forces on the returning blade.

Answer

The displacement of the stall regions in the inner area of the rotor blade.

Answer

The interference drag during low rates of descent.

Answer

The landing gear during the touchdown.

Question 32

What relieves the helicopter in a low G manoeuvre?

Accepted Answer

Increased vertical airflow through the rotor

Answer

Weightlessness of the passengers during the push over

Answer

Rolling movement of the helicopter to the right

Answer

Centrifugal force in parabolic flight during the entire manoeuvre

Question 33

The beam theory enables statements about the...

Accepted Answer

Power requirements during hover flight

Answer

Energy conversion in an autorotation.

Answer

Transition lift close to the ground.

Answer

Drag in cruise flight.

Question 34

Without corrective moves, a helicopter hovering in ground effect in no-wind conditions, will execute...

Accepted Answer

Slight upward and downward movements.

Answer

Pitching motion about the centre.

Answer

Fast yaw motions.

Answer

Rolling movements to about 60°.

Question 35

What is the effect of vortex ring state?

Accepted Answer

High rate of descent and irregular pitch, roll, and yaw motions

Answer

Stable descent and high-frequency vibrations in the helicopter

Answer

Decreased rate of descent and strong vibrations from the engine

Answer

Fluctuations in rotor and engine RPM

Question 36

A helicopter with a rotor turning in an anti-clockwise direction seen from above, hovers sideways to the right. What is the azimuth angle where the main rotor blades have the biggest pitch angle?

Accepted Answer

180°

Answer

270°

Answer

90°

Answer

0°

Question 37

Vy is the speed...

Accepted Answer

For the best rate of climb.

Answer

To rotate.

Answer

For the best angle of climb.

Answer

Never to be exceeded.

Question 38

During an autorotation a helicopter accelerates from 60 to 90 knots without further corrections. The rotor RPM will...

Accepted Answer

Decrease.

Answer

Remain constant.

Answer

Vary.

Answer

Increase.

Question 39

The rotor blade shape takes effect on the...

Accepted Answer

Lift distribution.

Answer

Rotor head used.

Answer

Noch sensitivity.

Answer

Structural take-off mass.

Question 40

What is the advantage of a turbulent airflow compared to a laminar airflow at an aerofoil with a high angle of attack?

Accepted Answer

It adheres to the aerofoil for a longer time

Answer

It has a thinner boundary layer

Answer

It has no form drag

Answer

The separation point moves further forward

Question 41

The transitional lift can be noticed by...

Accepted Answer

Vibrations.

Answer

An aural warning.

Answer

Strong load factors.

Answer

A loss of engine rpm.

Question 42

Why do helicopters with a semi-rigid rotor system react slower than others?

Accepted Answer

The central flapping hinge does not transmit any moments

Answer

The missing lag hinges cause a rotor imbalance

Answer

The lowered attachment of the rotor blades allows a transmission of forces

Answer

The angled lag hinges prevent the transmission of aerodynamic forces on the helicopter frame

Question 43

The pitch angle of a tail rotor blade is changed...

Accepted Answer

Collectively.

Answer

Cyclically.

Answer

Symmetrically.

Answer

Asymmetrically.

Question 44

What is the result of the vortex ring state?

Accepted Answer

The sink rate increases uncontrollably

Answer

The helicopter is more stable

Answer

The helicopter loses power

Answer

The rotor RPM increases

Question 45

Why does a stall begin on the retreating rotor blade at high cruise speeds?

Accepted Answer

The large pitch angle and relatively low peripheral speed cause a large effective angle of attack

Answer

The airflow reaches subsonic speed and causes an increase of the induced drag

Answer

The small pitch angle and a relatively low peripheral speed cause a small effective angle of attack

Answer

The airflow reaches supersonic speed and causes an increase of the parasite drag

Question 46

What shape of a rotor blade has a positive impact on the lift distribution?

Accepted Answer

Double trapezoidal rotor blade with a radius at the blade tip

Answer

Rectangular blade with a geometric setting of 1°

Answer

Trapezoidal blade without radius at the blade tip

Answer

Rectangular trapezoidal blade with no aerodynamic twist

Question 47

The maximum range in an autorotation will be achieved by...

Accepted Answer

A relatively high effective angle of attack.

Answer

A relatively low effective angle of attack.

Answer

A neutral effective angle of attack.

Answer

A negative effective angle of attack.

Question 48

The ground effect is noticeable by...

Accepted Answer

Lower power requirements.

Answer

Strong vertical oscillations.

Answer

Strong horizontal vibrations.

Answer

Larger power requirements.

Question 49

Which movement is caused by the Coriolis effect on the advancing rotor blade?

Accepted Answer

Drag movement forwards

Answer

Mass movement outwards

Answer

Tilt movement backwards

Answer

Flapping downwards

Question 50

The reason for a stall at a given pitch angle can be...

Accepted Answer

Smaller vertical airflow through the rotor and constant peripheral speed.

Answer

Constant peripheral speed and great vertical airflow through the rotor.

Answer

Smaller effective angle of attack and small peripheral speed.

Answer

Smaller frontal resistance and turbulent airflow.

Question 51

What types of airflow can be observed around a rotor blade aerofoil?

Accepted Answer

Laminar airflow at the leading edge, turbulent airflow further back

Answer

Laminar airflow on the entire upper surface

Answer

Turbulent airflow at the leading edge, laminar airflow further back

Answer

Turbulent airflow on the entire upper surface

Question 52

An increase of stability in a helicopter causes...

Accepted Answer

A reduced controllability.

Answer

A decrease of general aviation safety.

Answer

An optimization of the maximum helicopter mass.

Answer

An enhancement of control under negative load factors.

Question 53

What is the correct way to counteract the vortex ring state?

Accepted Answer

Try to gain airspeed and enter autorotation

Answer

Raise collective and decrease rotor RPM

Answer

Raise collective and pull back the stick

Answer

Open throttle and pull back the stick

Question 54

The induced airflow on the rotor of a helicopter in level flight has the greatest value at the...

Accepted Answer

Rear rotor area.

Answer

Advancing rotor blade.

Answer

Retreating rotor blade.

Answer

Front rotor area.

Question 55

Which ratio corresponds to the rotor disc loading?

Accepted Answer

Helicopter mass / rotor disc

Answer

Rotor disc / helicopter mass

Answer

Rotor thrust / rotor disc

Answer

Rotor thrust / rotor disc

Question 56

A delta-three hinge is used to allow...

Accepted Answer

For a decreased pitch angle at an upwards flapping blade.

Answer

The advancing blade to flap up about the hinge.

Answer

The advancing blade to lead about the hinge.

Answer

The advancing blade to drag about the hinge.

Question 57

Which option describes the term "asymmetric airflow"?

Accepted Answer

During cruise flight the advancing rotor blade has more airflow than the retreating rotor blade

Answer

The displacement of the driving forces to the advancing rotor blade in a vertical autorotation

Answer

The difference in required performance during hover in and out of ground effect

Answer

The greater lift in the outer region of the rotor as opposed to the inner region

Question 58

The airframe of an accelerating helicopter continues to bend until the...

Accepted Answer

Horizontal thrust component equals the drag.

Answer

Thrust passes in front of the centre of gravity.

Answer

Vertical thrust component equals the drag.

Answer

Thrust passes behind the centre of gravity.

Question 59

The effective angle of attack is the angle between...

Accepted Answer

Effective airflow and chord line.

Answer

Chord line and tip path plane.

Answer

Tip path plane and rotor blade.

Answer

Effective airflow and tip path plane.

Question 60

What is the purpose of the vertical stabilizer?

Accepted Answer

Improvement of directional stability

Answer

Adjustment of longitudinal stability

Answer

Compensation of tail rotor stability

Answer

Reduction of manoeuvre stability

Question 61

Which energies serve to maintain the rotor rpm in an autorotation?

Accepted Answer

Potential or kinetic energy

Answer

Mechanical or chemical energy

Answer

Rotational and linear energy

Answer

Frictional and flow energy

Question 62

What kind of drag is caused by a lift-producing aerofoil?

Accepted Answer

Induced drag

Answer

Parasite drag

Answer

Frictional drag

Answer

Interference drag

Question 63

What can be expected during a hover flight in ground effect within a forest glade?

Accepted Answer

Recirculation of air masses and an impairment of the ground effect

Answer

Useful ground effect caused by a smaller induced airflow

Answer

No air turbulence through the slipstream and stable attitude

Answer

Aspiration of the tail rotor in the direction of the forest and a performance gain

Question 64

Vx is the speed...

Accepted Answer

For the best angle of climb.

Answer

For the best rate of climb.

Answer

To rotate.

Answer

Never to be exceeded.

Exam simulation Principles of Flight (Helicopter) PPL(H) - Private Pilot License

Exam simulation PPL(H) EN Principles of Flight (Helicopter) 120 questions on 120 minutes