CADH Practice Cards 1 Flashcards
Random questions/statements for exam preparation
The helicopter you are flying has a fully articulated rotor system, on approach you notice a vibration coming from your main rotor. Upon landing it becomes so aggressive you need to abort, you have experienced …
Ground Resonance
Symmetrical aerofoils are normally used in helicopter blade design because they provide …
a small range of CP travel and good lift/drag ration over a wide range of speeds
Blade twist can be incorporated into rotor blade design to …
reduce lift towards the tips of the blade
When studying the behaviour of air we can cosdider it to be fluid. This means …
it has viscosity
An increase in gross weight effects the power required curve by …
causing it to move up and to the right
Ref: Principals of Helicopter Flight, Chapter 13 pg.107
Refer to vector diagram
The inflow angle is represented by letter …
D
The advantage of shutting down your helicopter with the wind coming from the 3 o’clock position….
will avoid your main rotor contacting the tail boom
When hovering close to buildings or other hovering helicopters, a loss of lift may occus due to …
recirculation
Fully articulated rotor systems have the ability to …
feather, flap and drag (lead/lag).
During take off outside the hanger in a max TOW helicopter, your power demand is increasing and your need to use aft cyclic. You are experiencing …
Recirculation.
Total air pressure is a result of the …
static air pressure and the dynamic air pressure combined
Refer to rotor blade diagram
The station on the blade which produces the greatset amount of lift is …
B, because it is not influenced by the rotor tip vortex which reduces efficiency at A
Induced flow is …
undesirable
Ref: Principals of Helicopter flight, chaper 6.
Flap back is a phenomenon experienced in accelerated flight. It will cause …
the nose of the helicopter to pitch up
Ref: Principals of Helicopter Flight, chapter 12, pg. 94
Hovering IGE (HIGE) is only useful when the helicopter is within …
one rotor radius of the groud meaused from the rotor hub
Static pressure is produced by …
weight of the atmosphere, and is exerted equally in all directions
Vortex ring state (VRS) is likely to occur duiring a…
high rate of desent with slow forward moving airspeed such as a vertical approach at high power into a hollow surrounded by trees
Ref: Principals of Helicopter Flight, Chapter 19, pg. 157
Hovering ceiling (maximum altitude at which the helicopter can hover) in ground effect (IGE) is …
greater than the hovering ceiling out of ground effect
During IGE, the rotor tip vortex are …
reduced.
During a slope landing with left skid on the ground, you lower the collective and hear a noise from the main rotor hub. You have just experienced …
Mast bumping
Ref: Principles of Helicopter Flight, Chapter 19, pg.167
Dynamic pressure is produced by …
force of the wind speed and sthe air density
IGE, the air pressure or density is increased, which acts to….
decrease the downward velocity of air
Effective Translational Lift is experienced with…
wind or forward airspeed between 10-12kts
Gyroscopic Precession is when…
any force applied to a rotating disc is felt 90d in the direction of rotation.
In a stick fixed condition, in forward flight, a helicopter experiences….
static and dynamic stability in the yawing plane.
Ref:
Tail rotor drift is compensated for by….
tilting the mast to the left (for rotors spinning anit-clockwise) and to the right (for rotors spinning clockwise)
The corrective actions for loss of tail rotor effectiveness (LTE) is to….
simultaneously lower your collective (if height permits), push forward on the cyclic and apply left peddle to counteract yaw.
When a conventional helicopter experiences Effective Translational Lift the nose of the helicopter will…
yaw left.
Ref: Principales of Helicopter Flight, Chapter 12, pg.99
During autorotation, if the cyclic is moved aft, rotor RPM will…
increase, then return back to its original RRPM
Rotorcraft VNE is a term usually related to …
retreating blade stall, it is expressed as a IAS and it decreases with increased pressure altitude or increased ambient temperature
Overpitching could be rectified by …
Lowering collective and opening throttle
An autorotative flare before landing is desirable to …
decrease rate of descent and forward airspeed
When the cyclic stick is moved forward in a helicopter with no advance angle you would expect the swash plate to …
tilt right
A helicopter in forward flight is …
dynamically stable and statically stable in the yawing plane only
The Centre of Pressure of an aerofoil is …
a point along the chord line of an aerofoil through which the resultant or total reaction of all aerodynamic forces is said to act
In autorotation the rotor exerts friction on the transmission tending to …
yaw the aircraft left
With a delta three hinge, the flapping hinge is set at an angle so that …
when the blade flaps the pitch angle is altered
Over pitching is caused by …
increasing collective to the extent that engine power cannot overcome rotor drag
An aerofoil produces lift by …
deflecting the airflow and causing an increase in velocity of the air flowing over the top surface
Refer to diagram
The diagram shows a rotor blade in …
the autorotative drag region
