Theory of flight Qs

Question 1

Name the secondary flight controls?

Answer 1

Flaps, Slats, THS, Spoilers

Question 2

Which axis does the Rudder act on?

Answer 2

Vertical Axis

Question 3

On which axis does the Elevator act on?

Answer 3

Lateral Axis

Question 4

On which axis does the Aileron act on?

Answer 4

Longitudinal

Question 5

What is a flight control trim system used for?

Answer 5

To maintain an equilibrium of an aircraft during flight without using a steering force

Question 6

Name some types of high lift devices used on a modern jet aircraft?

Answer 6

Slots, Slats, Flaps

Question 7

Separation of the boundary layer causes the wing to stall, name some boundary layer control devices?

Answer 7

Sweeping back wings, Vortex Generators, Fences or Saw tooth/dog tooth

Question 8

What is the function of a servo tab?

Answer 8

A tab on the flight control surface assists to help move the control surface

Question 9

What is the function of a trim tab?

Answer 9

A trim tab will be moved to crease an aerodynamic force that will move the control surface and hold it deflected.

Question 10

How does a balance tab work?

Answer 10

The control rod for a surface is attached to the underside of the tab and the underside of the fixed wing.

Question 11

How does a Spring Tab work?

Answer 11

When control forces are high the spring will compress and this moves a rod connected to the tab to reduce the overall force on the surface.

Question 12

What is the purpose of mass balancing?

Answer 12

To prevent control surface flutter

Question 13

How is flutter prevented?

Answer 13

Using mass balancing where weights are added in front of the hinge line to bring the center of gravity closer to the hinge.

Question 14

Speed of sound is affected by the ……………… of the air

Answer 14

Temperature

Question 15

What is the critical Mach number?

Answer 15

This is the number where the first indication of sonic flow (normal shockwave) forms somewhere on the wing

Question 16

The speed range below Mach 0.75 is?

Answer 16

Subsonic

Question 17

The speed range between Mach 0.75 - 1.20 is?

Answer 17

Transonic

Question 18

The speed range between Mach 1.20 - 5 is?

Answer 18

Supersonic

Question 19

The speed range greater than Mach 5 is?

Answer 19

Hypersonic

Question 20

In low speed flight air is considered to be?

Answer 20

Incompressible

Question 21

In high speed flight air is considered to be?

Answer 21

Compressible

Question 22

What are the 3 types of pressure waves?

Answer 22

Normal an Oblique shockwaves and expansion waves

Question 23

An oblique shockwave is?

Answer 23

Supersonic air striking a sharp edged airfoil that is forced to turn.

Question 24

Increasing the critical Mach number by effectively decreasing the thickness ratio of the wing is?

Answer 24

Sweepback on the wings

Question 25

Explain the definition ‘rotor blade angle’?

Answer 25

The angle between the rotor blade chord and the reference plane.

Question 26

Explain the definition ‘rotor angle of attack’?

Answer 26

The angle between the chord line of the airfoil and the relative wind

Question 27

What is the feathering axis?

Answer 27

The axis on which the pitch is changed

Question 28

What is the collective used for?

Answer 28

To raise or lower ALL the aircraft by changing the pitch

Question 29

What is the cyclic used for?

Answer 29

To raise or lower some blades and used in a turn.

Question 30

What are the foot pedals of a helicopter used for?

Answer 30

To steer the helicopter by counteracting or assisting the torque