CADH Practice Cards 2 Flashcards
Random question/statements for exam preparation
Raising the collective, collectively changes the pitch….
an equal amount relative to the rotor hub
Ground effect is lost at …
10-12 kt
In crusing flight you experience a high frequesncy vibration, this could be caused by …
tail rotor drive shaft out of balance
The load factor for a 60 degree angle of bank is…
2.0 (twice the weight)
One major issue to consider when flying at a high AUW is…
if an engine failure were to occur there may not be enough collective available for a safe termination on the ground
Transverse flow causes a conventional helicopter to …
roll to the right (inflow roll)
Winds from the 9 o’clock position can produce…
tail rotor vortex ring state
An increase of the coning angle will increase …
rotor RPM
Refer to Power Curve Diagram
The line labelled by the letter F is …
power available at low DA
Refer to diagram
The speed represented by the letter A is the speed for …
best angle of climb
Bernoulli’s theorem states …
that total pressure is comprised of static and dynamic pressure and total pressure will remain constant unless energy is added.
A semi-rigid rotor system has freedom to….
feather and flap
One of the reasons for using symmetrical aerofoils over asymmetrical aerofoils is…
Limited movement of the centre of pressure (C of P)
Refer to vector diagram
The letter J represents
rotor drag
Increasing headwind will effect your endurance?
True or False
False. wind does not effect the endurance of a helicopter
Ground resonance is most likley in helicopters with …
fully articulated rotor heads and shock absorbing landing gear
If no anti-torque control was provided the fuselage of the conventional helicopter would …
rotate to the right
Tail rotors use approximately _% of engine power?
10%
Delta 3 hinges are employed in tail rotor design to minimise…
flapping angles
Forces that will increase the coning angle of a rotor disc are…
a decrease in the centrifugal force (RRPM) or an increase in the total rotor thrust (TRT)
Tail rotor roll in a conventional helicopter is compensated for by….
offsetting the mast to the left
The hover height at which ground effect becomes negligible is…
one rotor disc diameter.
A high frequency buzz is most likely coming from…
an out of balance tail rotor
Refer to vector diagram
Total reaction force is represented by letter …
K
Blade taper is…..
a reduction in surface area from the root to the tip
A scenario that is most likely to give you mast bumping is….
a low to negative G light manoeuvre
Ref: Principles of Helicopter Flight, Chapter 19, pg. 167
The vector that replaces induced flow during autorotation is…
descent flow.
The rotor of the conventional helicopter provides for …
all actions as unit, collective relative to the hib, cyclic relative to the mast
You are departing from a HLS beside a large solid object, you should consider….
Avoid hovering beside the object as much as possible.
Autorotation’s with high AUW and high density altitudes can cause…
high rotor RPM
A conventional helicopter is hovering with a strong crosswind coming from the right. If loss of tail rotor effectiveness (LTE) were experienced, it would be most likely caused by …
a low tail rotor angle of attack and high tail rotor induced flow
Part 61 MOS Schedule 3 Unit 1.3.3 CADH 2.2.3 LTE
Refer to the Vector Diagram Below.
The diagram represents the forces and airflow on a section of rotor blade during a steady hover in nil wind.
Vector G represents the …
induced flow
Part 61 MOS Schedule 3 Unit 1.3.3 CADH 2.2.1 Label Vector Diagram for Hovering Flight
The flapping action of a fully articulated main rotor system in sideways flight causes the advancing blade to …
rise and accelerate
Part 61 MOS scedule 3 Unit 1.3.3 CADH 2.3.1 Flapping
The reason why main rotor blades of most helicopters are symmetrical is to provide for the …
limited movement of the centre of pressure throughout all phases of flight
Part 61 MOS Scedule 3 Unit 1.3.3 CADH 2.1.1 Aerodynamic Properties of a Rotor Blade - Shape
The total reaction force is defined as …
the resultant of the pressure forces acting on an aerofoil
Part 61 MOS Scedule 3 Unit 1.3.1 CADC 2.2.1 Bernoulli’s Theorem
Drag is defined as …
the component of total reaction acting parallel to the relative airflow
Part 61 MOS Scedule 3 Unit 1.3.1 CADC 2.2.1 Bernoulli’s Theorem
The component of total reaction acting in the plane of rotation opposite to torque is called …
rotor drag
Part 61 MOS scedule 3 Unit 1.3.3 CADH 2.1.2 Rotor Drag
The component of total reaction acting parallel to the relative airflow is called …
drag
Part 61 MOS scedule 3 Unit 1.3.1 CADC 2.4.1 General Helicopter Aerodynamics - Drag
The helicopter is autorotating in nil wind at the airspeed recomended for maximum range, with rotor RPM at the bottom of the green arc. If you maintain the same airspeed, lowering the collective will …
reduce endurance
Part 61 MOS Schedule 3 Unit 1.3.3 CADH 2.6.1 Effect on Autorotative Flight on Variations in RRPM
The most likley time that LTE would be experienced is …
low airspeed manoeuvers with high main rotor pitch
Part 61 MOS Schedule 3 Unit 1.3.3 CADH 2.2.3 LTE
