General knowledge

Question 1

What errors are vertical speed indicators subject to?

Answer 1

1) lag error

2) reversal-in about changes in attitude the VSI may momentarily show a change in the wrong direction

Question 2

Define: Yaw

Answer 2

movement of aircraft around the vertical axis

Question 3

Define: Roll

Answer 3

movement of an aircraft around the longitudinal axis

Question 4

What is relative humidity?

Answer 4

amount of moisture present in the air compared to amount it is capable of holding

Question 5

In extremely cold temperature the altimeter will___________?

Answer 5

over-read

Question 6

Define: Ground Resonance

Answer 6

is a sympathetic vibration between the main rotror system and landing gear when the helicopter is touching the ground
Note: generally only fully articulated rotor systems are susceptable

Question 7

On turns to or from North the magnetic compass will _____________ the actual reading

Answer 7

lag behind

Question 8

What are Newtons laws of motion?

Answer 8

1) A body in motion tends to stay in motion
2) An object at rest tends to stay at rest until acted on by another force
3) for every action there is an equal and opposite reaction

Question 9

What are five principle agents that initiate rising currents of air?

Answer 9

1) convection- air heated by contact with ground
2) Orographic lift-air moving up hill continues upwards especially if unstable
3) Frontal Lift-air masses meet the warmer air is pushed up
4) Mechanical Turbulence-friction between air and ground disrupts lower level air into eddies
5) Convergence- low pressure area, winds are blowing into centre of low and accumulating, the excess air is forced upwards

Question 10

What is atsmopheric pressure?

Answer 10

is the weight of overlying air measured with a mercury barometer

Question 11

list three causes of ground resonance

Answer 11

1) Faulty rotor system-weak drag hinge dampers, badly tracked or balanced rotor blades

Question 12

list and describe the different types of drag

Answer 12

Parasite-created by moving objects
Rotor-Caused by rotor blades in flat or zero pitch
Induced drag- occurs when blades are at a positve angle of attack(producing lift)Induced drag is high in the hover but reduces with translational lift and increased forward speed

Question 13

Define: Dissymetry of lift

Answer 13

The relative airspeed travelling over the retreating blade is less than the advancing blade resultaning in unequal lift on the blades

Question 14

Define: Ground effect

Answer 14

s

Question 15

Define: Translating tendency

Answer 15

s

Question 16

Define: horizontal from the hub

Answer 16

Refrence datum on the hub of the main rotor

Question 17

What factor affect the rate of descent in autorotation

Answer 17

weight-heavier=higher rate of descent
Forward speed-above or below the minimum rate of descent speed will result in a higher rate of descent
Density altitude-rate increases with an increase of density altitude

Question 18

Define Torgue effect

Answer 18

Blades spin counter-clockwise causing an opposite reaction on fuselage turning it clockwise

Question 19

define: Recirculation

Answer 19

Aceleration of induced air through the disc

Question 20

Define: Vortex ring state

Answer 20

Intense vortices from induced flow, reenter the rotor blades reducing the lift produced. usually encountered at configurations with an airspeed below 30knots, and a rate of descent higher than 300FPM

Question 21

Define: Chord line

Answer 21

A straight line running from leading edge to trailing edge of an aerofoil

Question 22

describe feathering movement of a rotor blade

Answer 22

angular movement of a rotor blade about its longitudinal axis
*any change of pitch is a feathering movement

Question 23

Define: Induced flow

Answer 23

The rotor blades displace air downwards through the rotor disc

Question 24

Define Pitch angle

Answer 24

The angle between the chord of a rotor blade and a refrence datum on the hub of the rotor.

Question 25

Define: Convection

Answer 25

Warm air rises owing to the heating of the ground by the sun, risng currents of air occur

Question 26

Describe the flapping movement of a rotor blade

Answer 26

the automatic angular movement of a rotor blade about a horzontal axis

Question 27

What are the main types of rotor systems and describe each

Answer 27

Fully articulated- blades allowed by hinges to flap, drag and feather Semi-rigid-the blades are allowed by hinges to flap and feather, underslung rotor Rigid- only feathering hinge

Question 28

Name 2 types of control orbits

Answer 28

Swash plate | Spider

Question 29

Define: dragging of a rotor blade

Answer 29

The angular movement of an individual rotor blade about an axis vertical to the blade

Question 30

What is an transition? translation?

Answer 30

Transition-all accelerations or decelerations of the helicopter as a result of cyclic change Translation- horizontal movement of the helicopter through the air

Question 31

Define: Indicated altitude

Answer 31

The reading on the altimeter when it is set to current barometric pressure

Question 32

Define: Coning

Answer 32

Movement of rotor blades aligning them along the resultant angle of centrifugal force and lift, an increase in lift results an increase in coning angle. An increase of RPM results in a decrease of coning angle

Question 33

Define: Camber line

Answer 33

A line drawn halfway between upper and lower surface of an aerofoil

Question 34

Define angle of attack

Answer 34

The angle between the chord and relative airflow

Question 35

What are 5 factors that affect lift

Answer 35

1) angle of attack of aerofoil 2) airflow velocity 3) air density 4) shape of airfoil 5) surface area of airfoil

Question 36

Define: Overpitching

Answer 36

Blades pitch-up increasing drag, not enough power to overcome drag

Question 37

Define: Pitch (as in pitch, roll, yaw)

Answer 37

movement of aircraft around the lateral axis | *lateral axis-wing tip to wing tip

Question 38

Name the instruments connected to the pitot/static system and from which they get there data from.

Answer 38

Altimeter-static Vertical speed indicator-static Airspeed indicator-staic and pitot

Question 39

Define: Delta hinge

Answer 39

hinge located on the tail rotor, is ofsetto be non-perpindicular to the axis of the tail rotor

Question 40

Define: Low G

Answer 40

unloading of the disc usually caused by a push over

Question 41

Define: High G

Answer 41

aircraft experiances load factor greater than 1G due to a turn, climb, or deceleration

Question 42

Define: True altitude

Answer 42

Exact height above sea level

Question 43

What are low frequency vibrations usually associated with? High? Low?

Answer 43

low-main rotor medium-tail rotor High- engine