CADH Practice Cards 5 Flashcards
Random questions/statements for exam preparation
Flapping to equality means…
Allowing the blades to flap of thier own accord, increasing and decreasing pitch angles by the adjustment of induced flow to increase and decrease lift respectively.
The inflow angle is defined as …
the angle between the relative airflow and the rotational flow
Refer to diagram
THe diagram shows a rotor blade in …
the autorotative drive region
Dissymmetry of lift is over come by …
allowing blades to flap
Rotational airflow is..
Airflow due to the actual rotation of the blade, parallel to the plane of rotation.
Refer to diagram
Lift is represented by the vector …
D
The diagram is of the autorotative drag region
Ground resonance may be caused by …
a geometric imbalance of a fully articulated rotor system
The relative wind angle that will produce weathercocking is….
180 degrees.
Refer to vector diagram -
Induced flow is represended by the letter …
G
The mean camber line of an aerofoil is a line …
drawn halfway between the upper and lower surfaces of an aerofoil, starting at the centre of curvature of the leading edge and ending at the centre of the training edge
The total reaction force is defined as …
the resultant of the pressure forces acting on an aerofoil
In a hover left turn, the tail rotor …
pitch increases
Raising the collective will….
Collectivly change the pitch (and equal amount) relative to the rotor hub.
Aircraft designers can incorporate a feature into the blade design to prolong the effect of comressibility, this is known as…
Swept back tips
Lift is defined as …
the component of total reaction acting perpendicular to the relative airflow
Three benifits of a flare are…
Decrease ROD, decrease FWD airspeed and Increase RRPM
Refer to diagram
Drag is represented by the vector …
G
The diagram is of the autorotative drag region
In overcoming dissymmetry of lift, the angle of attack on the advancing blade …
decreases
The relative airflow presenting to an aerofoil is defined as …
the single airflow presented to an aerofoil after adding up all the smaller airflow components
In cruise you experience low rotor RPM and low manifold pressure. To remedy this you would …
increase throttle
During autorotation the pilot controls the rotor RPM by using …
the collective
What does the swashplate do …
applies cyclic and collective control to the main rotor
Hovering in ground effect (HIGE) would be most useful when…
hovering at high density altitudes with high AUW
Ref: Principles of Helicopter Flight, Chapter 11, pg. 81
A one-per-rev vertical vibration can be caused by a…
Out of track main rotor.
Principles of Helicopter Flight, Chapter 20
Refer to vector diagram -
Lift is represented by the letter …
M
Two indicators of a sudden increase in headwind during approach to land would be….
an increase in indicated airspeed and a decrease in rate of descent.
Drag is defined as …
the component of total reaction acting parallel to the relative airflow
When the angle of attack increases, drag increases and lift decreases.
True or False?
False
During forwards autorotation, the pattern of driving and propeller region distribution over the disc is …
moved toward the retreating side
Induced drag at the blade tip is know as…..
Vortices
In relation to aerodynamics, high air density can….
increase engine power, increase thrust and increase lift.
The plane of rotation is defined as …
the plane passing through the rotor hub parallel to the plane in which the blades rotate
Assuming all other factors are equal, a decrease in airspeed will require an increase in angle of attack to stay in straight and level flight.
True or False?
True.
The effect that a headwind will have on the ROC is…
none, the ROC remains unchanged, however the angle at which the aircraft will climb will be effected.
Angle of attack and airspeed are inherently linked, so in a straight and level flight we can assume…..
that as airspeed increases, angle of attack decreases.
A standard rate turn can be completed in…
2 minutes.
if you double the spped in a turn for a given bank angle, the radius will….
quadruple.
Ground effect is most noticeable…
Just above the ground
Load factor equals….
Lift / Weight
The tip path plane is defined as …
the plane passing through the blade tips parallel to the plane in which the blades rotate
