CADH Practice Cards 9 Flashcards
Random questions/statements for exam preparation
Refer to vector diagram
Vector I acts parallel to …
the relative airflow
The most common method of starting the engines on a large civilian helicopter is …
electric starter motors
A helicopter with an anti-clockwise rotating main rotor system is hovering to the left in nil wind. The maximum angle of attack is at position …
6 o’clock or aft of the aircraft
A common recovery action to correct retreating blade stall, and settling with power is …
decrease angle of attack
Helicopter rotor diameter is 35 ft, it is operating at 2600 lb AUW. The approximate disc loading is …
2.6 lb/sq ft
The coning angle refers to …
the smaller angle between the tip path plane and the logitudinal axis of the blade
Refer to diagram
The vector labelled E is …
total reaction
The diagram is of the autorotaive drive region
The term ‘Soft in Plane’ is associated with …
the leading and lagging freedom of the main rotor blades
Ground effect is useful to a height of …
half a rotor diameter
Refer to the diagram
The vector labelled H is …
autorotative force
The diagram is of the autorotaive drive region
One of the main causes of hunting is …
geometric imbalance
The swash plate is used to …
transfer cyclic and collective control movements to the rotor disc
The best angle of climb airspeed in a helicopter which has the ability to hover OGE is …
mainly dependant on the power available
Refer to vector diagram
Vector J acts perpendicular to …
rotor thrust
Coning angle will increase is thrust …
increases, or centrifugal force (rotor RPM) decreases
To hover over a spot, minimum power will be required when the wind speed is approximately …
50 kt
During a steep approach to land with an IAS of 8 kt and a high relative ground speed you may experience problems with yaw control due to …
weather cock stability and LTE issues
To settle with power the following conditions are required …
a descent rate, nearly zero airspeed, power applied
The cyclic control on a helicopter alters the …
pitch on each blade consecutively and independently of the other blades (relative to the mast)
Main rotor reverse thrust is most useful on a large helicopter to …
pin it to the deck of a moving vessel or helideck
A rotor aerofoil section is symmetrical because …
it minimises movement for the centre of pressure in all flight conditions
Refer to Power Curve Diagram
The speed represented by the letter E is the speed for …
maximum excess power
When taxiing rapidly sideways to the left, the helicopter experiences uncommanding yawing. Unless careful attention to pedal input is made the helicopter may experience …
uncontrolled yawing to the right due to vortex ring induced LTE
Flapback is compensated by …
cyclic feathing
What is the rate of descent required to induce settling with power …
300 ft/min
You notice that engine RPM is high and manifold pressure is low, the action you would take is …
decrease throttle, increase collective
The collective control on a helicopter changes the …
pitch of each blade an equal amount (relative to the hub)
The term ‘Disc Solidity’ refers to …
the ratio of blade area to disc area
The first rotor system to incorporate a flapping hinge was designed by …
Juan de la Cierva
Overpitching is caused by …
the engine at a given power setting being unable to overcome rotor drag
The vibration associated with transverse flow effect (inflow roll) is caused by …
loss of lift over the rear of the disk
The rigid rotor has …
feathering freedom only
Refer to Power Curve Diagram
The speed represented by the letter D is the speed for …
maximum forward speed
Retreating blade stall is most likely to occur at …
high speed, low RPM, steep turn
A semi ridged rotor can …
feather, flap and cone
Flapping is movement of the rotor blades which help …
overcome dissymmetry of lift in forward flight
Advantages of a shrouded (Fenestron) tail rotor over a conventional tail rotor are …
elimination of asymmetry of lift means the blades only need feathering freedom and not flapping freedom
During normal approach to land in light wind at a HLS located within a ground hollow, a hazardthat needs special attention is …
re-circulation prior to shutdown
