CADH Practice Cards 4 Flashcards
Random questions /statements for exam preparation
A design feature employed to eliminate phase lag is called…
the advance angle
What causes the total power required curve to increase after minimum power speed?
A combination of parasite drag and profile drag
What are trim tabs used for in helicopter rotor systems?
Tracking of the main rotor
Ref: Principles of Helicopter Fligt, Chapter 20
Refer to vector diagram
Rotor thrust is represented by the letter …
N
Daniel Bernouli is remembered for his investigation of …
fluid dynamics
When the tail rotor reaches effective translational lift the nose of the conventional helicopter will …
yaw left
Departing an aerodrome at high density altitude and igh AUW without careful power management can cause….
Over-pitching
What vector replaces induced flow during autorotation?
Descent flow
The term ‘Blade Sailing’ can be described as….
Blade sailing is a phenomenon which occurs on shut down or start up wen the rotor RRP is too low for centrifugal force to prevent the blades from flapping excessively in windy conditions
Ref: Principles of Helicopter Flight, Chapter 19
On take off you realize that your right skid is dragging on the ground. What should you do to prevent dynamic rollover?
Apply left cyclic and increase collective
a 30kt tailwind will cause the TAS for best range to ….
Decrease
Bernouli’s theorem states that …
total pressure =
static pressure +
dynamic pressure
Refer to the vector diagram
The letter I represents …
drag
When flying a helicopter with a fully articulated rotor system and fitted with oleo strut shock absorbers, you notice a ‘wobble’. On touch down this wobble turned into extreme vibrations. You are experiencing…
Ground Resonance. If RRPM permits, increase collective and return to the hover.
Ref: Principles of Helicopter Flight, Chapter 19
Trim Tabs are used for?…
Tracking of the main rotor
In the conventional helicopter, the percentage of total available power used for torque control is approximately …
10-15%
In respect to a conventional helicopter, if you have a large positive pitch what will occour?
Yawing to the left
If you have an increase in headwind, this will cause the speed for best range to…..
Increase
Ref: Prinicples of Helicopter Flight, Chapter 13
The level pressure in the ISA is assumed to be approximately …
14.2 psi
Offsetting the mast to the left in a conventional rotor system will compensate for….
tail rotor roll.
The bottom of the power curve depicts the maximum excess power for a given airspeed, you can also find the….
Minimum power, best endurance and best rate of climb (ROC)
In a stick free condition, the helicopter is….
statically and dynamically unstable
The TAS for best angle of climb (AOC) is calculated on the power curve by….
drawing a tangesnt from the power available until it intersects the curve.
Ref: Principles of Helicopter Flight, Chapter 13
The formula used to calculate Disc Loading is …
gross weight/disc aera
