PPL(H) 52 Grundlagen des Fluges (Hubschrauber)

Transcription

1 Part-FCL Fragenkatalog PPL(H) gemäß Verordnung (EU) 1178/2011 und AMC FCL.115,.120, 210,.215 (Auszug) 52 Grundlagen des Fluges (Hubschrauber)

2 Herausgeber: AIRCADEMY LTD. LPLUS GmbH COPYRIGHT Vermerk: Dieses Werk ist urheberrechtlich geschützt. Die kommerzielle Nutzung des Werkes oder Ausschnitte aus dem Werk in Lehr- und Lernmedien ist nur nach vorheriger Zustimmung durch die Herausgeber erlaubt. Für Anfragen wenden Sie sich bitte an die Herausgeber Bitte beachten Sie, dass dieser Auszug ca. 75% der Aufgaben des gesamten Prüfungsfragenkataloges enthält. In der Prüfung werden auch unbekannte Aufgaben erscheinen. Revision & Qualitätssicherung Im Rahmen der stetigen Revision und Aktualisierung der internationalen Fragendatenbank für Privatpiloten (ECQB-PPL) sind wir stetig auf der Suche nach fachkompetenten Experten. Sollten Sie Interesse an einer Mitarbeit haben, wenden Sie sich per an Sollten Sie inhaltliche Anmerkungen oder Vorschläge zum Fragenkatalog haben, senden Sie diese bitte an v

3 1 Which ratio corresponds to the rotor disc loading? (1,00 P.) Rotor thrust / rotor disc Helicopter mass / rotor disc Rotor disc / helicopter mass Rotor thrust / rotor disc 2 What causes the phase lag between the displacement and the flapping of a rotor blade? (1,00 P.) Inertia, mass, and aerodynamic forces Advance or retreat angle of 90 Friction in the rotor blade spindles Rounding of the rotor blade tips 3 If the critical angle of attack is exceeded, the... (1,00 P.) transition point starts moving towards the airflow direction. laminar boundary layer turns into a turbulent boundary layer. boundary layer on the upper side of the rotor blade begins to separate. boundary layer on the lower side of the rotor blade begins to separate. 4 What types of airflow can be observed around a rotor blade aerofoil? (1,00 P.) Laminar airflow on the entire upper surface Turbulent airflow on the entire upper surface Turbulent airflow at the leading edge, laminar airflow further back Laminar airflow at the leading edge, turbulent airflow further back 5 What is the advantage of a turbulent airflow compared to a laminar airflow at an aerofoil with a high angle of attack? (1,00 P.) It adheres to the aerofoil for a longer time It has no form drag It has a thinner boundary layer The separation point moves further forward 6 The virtual rotation axis of a rotor is... (1,00 P.) perpendicular to the hub plane. parallel with the main rotor shaft. perpendicular to the tip path plane. perpendicular to the plane which contains the swash plate. v

4 7 The effective angle of attack is the angle between... (1,00 P.) chord line and tip path plane. effective airflow and tip path plane. effective airflow and chord line. tip path plane and rotor blade. 8 What kind of drag is caused by a lift-producing aerofoil? (1,00 P.) Induced drag Frictional drag Parasite drag Interference drag 9 What force affects the braking torque of the rotor in cruise? (1,00 P.) Inclined forward lift Upward directional rotor thrust Inclined rearward tangential force Inclined forward drag force 10 The rotor thrust is... (1,00 P.) perpendicular to the tip path plane. perpendicular to the hub plane. parallel with the main rotor shaft. opposite to the rotation of the rotor blade element. 11 What happens to thrust and tangential force if the rotor RPM decreases by about 10 % in cruise flight? (1,00 P.) The thrust and the tangential force increase The thrust and the tangential force decrease The thrust remains constant and the tangential force increases The thrust decreases and the tangential force remains constant 12 The effective airflow velocity of a rotor blade element varies with the distance from the rotor shaft axis, because the... (1,00 P.) tangential force and airflow reversal vary. peripheral speed increases if the displacement to the rotor blade tip decreases. helicopter airframe disturbs the airflow. drag force in direction of the rotaion axis is increased. v

5 13 Which of the stated relationships between lift and drag applies best for a flying helicopter (lift : drag)? (1,00 P.) 45 : 1 2 : 1 1 : 45 1 : 2 14 The reason for a stall at a given pitch angle can be... (1,00 P.) smaller effective angle of attack and small peripheral speed. smaller vertical airflow through the rotor and constant peripheral speed. constant peripheral speed and great vertical airflow through the rotor. smaller frontal resistance and turbulent airflow. 15 The neutral point is a point where... (1,00 P.) the entire helicopter mass can be assumed to attack. the aerodynamic forces act torque-free. the torque at the chord line remains constant for changing angles of attack. the imaginary axes of a helicopter meet each other. 16 What shape of a rotor blade has a positive impact on the lift distribution? (1,00 P.) Rectangular blade with a geometric setting of 1 Trapezoidal blade without radius at the blade tip Double trapezoidal rotor blade with a radius at the blade tip Rectangular trapezoidal blade with no aerodynamic twist 17 The rotor blade shape takes effect on the... (1,00 P.) lift distribution. rotor head used. noch sensitivity. structural take-off mass. 18 The drive system of the autogyro's main rotor is based on... (1,00 P.) an engine in the cabin. a fan in the cabin. an engine at the rotor blade tip. the speed of the airflow. v

6 19 The rotor RPM is kept constant in the helicopter by the engine RPM. It can be influenced by the... (1,00 P.) collective. throttle and the governor. cyclic stick. starter and the impulse coupling. 20 The beam theory enables statements about the... (1,00 P.) drag in cruise flight. power requirements during hover flight. transition lift close to the ground. energy conversion in an autorotation. 21 During hover flight, the induced airflow velocity... (1,00 P.) increases further having passed the rotor. remains constant after having passed the rotor. is equal above and below the rotor. decreases after having passed the rotor. 22 Why is a helicopter's climb initially accelerated after an increase of the pitch angle? (1,00 P.) The initially high airflow increases the rotor thrust until the lower air density reduces the rotor thrust again 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 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 The conversion of energetic air into kinetic rotor energy decreases continuously with increasing density altitude 23 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? (1,00 P.) v

7 24 The airframe of an accelerating helicopter continues to bend until the... (1,00 P.) thrust passes in front of the centre of gravity. horizontal thrust component equals the drag. thrust passes behind the centre of gravity. vertical thrust component equals the drag. 25 What is the reason for retreating blade stall? (1,00 P.) Small pitch angle and large effective airflow Small cone angle and constant peripheral speed Large centrifugal forces of the peripheral speed Large pitch angle and small effective airflow 26 The induced airflow on the rotor of a helicopter in level flight has the greatest value at the... (1,00 P.) front rotor area. retreating rotor blade. rear rotor area. advancing rotor blade. 27 Which option describes the term "asymmetric airflow"? (1,00 P.) The displacement of the driving forces to the advancing rotor blade in a vertical autorotation During cruise flight the advancing rotor blade has more airflow than the retreating rotor blade The greater lift in the outer region of the rotor as opposed to the inner region The difference in required performance during hover in and out of ground effect 28 The transitional lift can be noticed by... (1,00 P.) an aural warning. vibrations. a loss of engine rpm. strong load factors. 29 Which statement about the rotor disc loading in a horizontal curve is correct? (1,00 P.) Effects depend on the type of helicopter It increases with increasing bank angle It decreases with increasing bank angle No change in relation to the cruise flight v

8 30 What action is necessary in a modern helicopter during the transition to a horizontal turn? (1,00 P.) Open the throttle in a helicopter with a rotor turning in an anti-clockwise direction seen from above Open the throttle in a helicopter with a rotor turning in a clockwise direction seen from above A control column movement forward or raising the collective A control column movement backward or raising the collective 31 Why does a stall begin on the retreating rotor blade at high cruise speeds? (1,00 P.) The airflow reaches subsonic speed and causes an increase of the induced drag The small pitch angle and a relatively low peripheral speed cause a small effective angle of attack The airflow reaches supersonic speed and causes an increase of the parasite drag The large pitch angle and relatively low peripheral speed cause a large effective angle of attack 32 Without corrective moves, a helicopter hovering in ground effect in no-wind conditions, will execute... (1,00 P.) slight upward and downward movements. pitching motion about the centre. fast yaw motions. rolling movements to about The ground effect is noticeable by... (1,00 P.) strong horizontal vibrations. larger power requirements. lower power requirements. strong vertical oscillations. 34 What can be expected during a hover flight in ground effect within a forest glade? (1,00 P.) Recirculation of air masses and an impairment of the ground effect Useful ground effect caused by a smaller induced airflow Aspiration of the tail rotor in the direction of the forest and a performance gain No air turbulence through the slipstream and stable attitude 35 Which landing site (no wind) prevents the impairment of the ground effect? (1,00 P.) Elevated helipad Plain terrain Narrow forest glade Sloping ground v

9 36 What is the result of the vortex ring state? (1,00 P.) The helicopter loses power The rotor RPM increases The helicopter is more stable The sink rate increases uncontrollably 37 What is the correct way to counteract the vortex ring state? (1,00 P.) Raise collective and decrease rotor RPM Try to gain airspeed and enter autorotation Open throttle and pull back the stick Raise collective and pull back the stick 38 What is the effect of vortex ring state? (1,00 P.) Stable descent and high-frequency vibrations in the helicopter Fluctuations in rotor and engine RPM High rate of descent and irregular pitch, roll, and yaw motions Decreased rate of descent and strong vibrations from the engine 39 What is the risk arising in a vertical autorotation with a subsequent increase in airspeed prior to the landing? (1,00 P.) Vortex ring state High rotor RPM Misjudgement when increasing the airspeed Loss of the tail rotor efficiency 40 What is the reason for the driving forces in an autorotation? (1,00 P.) Increased pitch angle Downward tilted effective airflow High airspeeds Low rate of descent 41 During an autorotation the airspeed is limited by... (1,00 P.) the interference drag during low rates of descent. the landing gear during the touchdown. the displacement of the stall regions in the inner area of the rotor blade. the drift of the driving forces on the returning blade. v

10 42 Which of the following options has an effect on the autorotation characteristics? (1,00 P.) Helicopter mass and density altitude Air temperature and wind speed Smoothly working tail rotor control and low RPM warning systems Pressure altitude and wind speed 43 During an autorotation with forward speed of a helicopter the driving forces are located in the... (1,00 P.) inner region. outer region. region of the advancing rotor blade. region of the retreating rotor blade. 44 During an autorotation a helicopter accelerates from 60 to 90 knots without further corrections. The rotor RPM will... (1,00 P.) increase. remain constant. decrease. vary. 45 What action has no effect on the rotor RPM in an autorotation? (1,00 P.) Centre of gravity displacement. Pitch angle change. Utilisation of friction brake. Transition into a turning flight. 46 After entering an autorotation a large helicopter mass leads to... (1,00 P.) a small rate of descent in a vertical autorotation. a large change in center of gravity. a rapid collapse of the rotor RPM. a rapid build-up of the rotor RPM. 47 What shall be considered before terminating a turn in an autorotation? (1,00 P.) The decreasing gravity relieves the main rotor and the helicopter cabin The Coriolis force causes an increase in the main rotor rpm The pitch angle must be decreased by using the collective pitch lever again The flight velocity shall be increased to obtain all the kinetic energy v

11 48 Which energies serve to maintain the rotor rpm in an autorotation? (1,00 P.) Rotational and linear energy Potential or kinetic energy Frictional and flow energy Mechanical or chemical energy 49 The maximum range in an autorotation will be achieved by... (1,00 P.) a relatively high effective angle of attack. a negative effective angle of attack. a relatively low effective angle of attack. a neutral effective angle of attack. 50 Why does a flare during an autorotation generate higher rotor RPM? (1,00 P.) The pitch angle increases The ground effect leads to better performance The vertical airflow through the rotor disc increases The tangential force tilts backwards 51 Which movement is caused by the Coriolis effect on the advancing rotor blade? (1,00 P.) Flapping downwards Drag movement forwards Mass movement outwards Tilt movement backwards 52 Which factor affects the available response time to initiate an autorotation after engine failure? (1,00 P.) Functionality of the coupling Inertia of the main rotor system Profile shape of the rotor blades Movement of the pressure point 53 Which statement about the required force to change the pitch angle is correct? (1,00 P.) It is the smallest by using an advance angle of 90 It must be greater than the tangential force It is the smallest by using a delta-three-hinge It must be greater than the rotor disc loading v

12 54 Why do helicopters with a semi-rigid rotor system react slower than others? (1,00 P.) The central flapping hinge does not transmit any moments The lowered attachment of the rotor blades allows a transmission of forces The angled lag hinges prevent the transmission of aerodynamic forces on the helicopter frame The missing lag hinges cause a rotor imbalance 55 The pitch angle of a tail rotor blade is changed... (1,00 P.) symmetrically. cyclically. collectively. asymmetrically. 56 A delta-three hinge is used to allow... (1,00 P.) for a decreased pitch angle at an upwards flapping blade. the advancing blade to lead about the hinge. the advancing blade to drag about the hinge. the advancing blade to flap up about the hinge. 57 What needs to be observed in conjunction with a temporary loss of tail rotor efficiency in a stationary hover? (1,00 P.) Mechanical blockage of the control Vortex ring stage of the tail rotor Rotating movement in the main rotor direction Loss of the main rotor thrust 58 What is caused by an increase of stability in a helicopter? (1,00 P.) A decrease of the required control forces An enhance of control under negative load factors An increase of general flight safety An optimization of the maximum helicopter mass 59 What is caused by an increase of stability in a helicopter? (1,00 P.) A decrease of the required control forces An enhance of control under all load factors A relief of the pilot in command An optimization of the maximum helicopter mass v

13 60 Why are the stability criteria of a helicopter very important? (1,00 P.) Low stability reduces the available control forces High stability prevents low load factors A lack of stability may lead to loss of control Large stability increases the maximum take-off mass 61 The helicopter's stability is increased by... (1,00 P.) decreasing the rotor mass. reducing the rotor RPM. attaching a stabilizer. pivoting the drag hinge. 62 What is the purpose of the vertical stabilizer? (1,00 P.) Improvement of directional stability Reduction of manoeuvre stability Adjustment of longitudinal stability Compensation of tail rotor stability 63 An increase of stability in a helicopter causes... (1,00 P.) a reduced controllability. an enhancement of control under negative load factors. a decrease of general aviation safety. an optimization of the maximum helicopter mass. 64 What behavior does a helicopter without stabilization systems show after external disturbances in a hover, without a corrective action? (1,00 P.) Statically stable and dynamically stable Statically stable and dynamically indifferent Statically indifferent and dynamically instable Statically stable and dynamically instable 65 What relieves the helicopter in a low G manoeuvre? (1,00 P.) Increased vertical airflow through the rotor Weightlessness of the passengers during the push over Centrifugal force in parabolic flight during the entire manoeuvre Rolling movement of the helicopter to the right v

14 66 Vx is the speed... (1,00 P.) never to be exceeded. for the best rate of climb. for the best angle of climb. to rotate. 67 Vy is the speed... (1,00 P.) never to be exceeded. for the best rate of climb. for the best angle of climb. to rotate. v