Quiz 1 For Structures

Front 1

Where is the buttock line or buttline of an aircraft?

Back 1

A width measurement left or right of, and parallel to, the vertical centerline

Front 2

An airplane wing that operates most efficiently at a high angle of attack has a _____.aspect ratio

Back 2

high

Front 3

In order to tilt the rotor disc of a helicopter forward, the pitch of the ________ blade is increased.

Back 3

retreating

Front 4

When supersonic air flows into a diverging duct, its velocity

Back 4

increase

Front 5

As the angle of attack of an airfoil increases, the center of pressure will

Back 5

move toward the leading edge

Front 6

The stall begins on a rectangular wing at the

Back 6

root

Front 7

When subsonic air flows into a diverging duct, its density

Back 7

remains the same

Front 8

When supersonic air flows into a converging duct, its velocity

Back 8

decreases

Front 9

An airplane stalls only when it reaches a critically

Back 9

high angle of attack

Front 10

The coriolis effect is most noticeable on ________-blade rotor systems

Back 10

three

Front 11

Movement of an airplane along its lateral axis (roll) is also movement

Back 11

around or about the longitudinal axis controlled by the ailerons.

Front 12

Vortex generators mounted on the empennage of an airplane improve flight characteristics at ________ speed

Back 12

low

Front 13

An airplane has positive longitudinal static stability when its center of gravity is ___________ the center of the lift.

Back 13

ahead

Front 14

The center pressure remains in essentially the same location as the angle of attack changes on a/an ___________ airf

Back 14

symmetrical

Front 15

The pitch of the rotor blade is changed at a particular point in their rotation by the _________ pitch control.

Back 15

cyclic

Front 16

An airplane's center of lift is usually located aft of its center of gravity

Back 16

so that the airplane will have a nose-heavy tendency.

Front 17

An airplane that has a tendency to gradually increase a pitching moment that has been set into motion has

Back 17

poor longitudinal stability

Front 18

Improper rigging of the elevator trim tab system will affect the balance of the airplane about its

Back 18

lateral axis.

Front 19

The elevators of a conventional airplane are used to provide rotation about the

Back 19

lateral axis.

Front 20

The coriolis effect causes the rotor blades to move

Back 20

back and forth

Front 21

The primary purpose of stall strips is to

Back 21

stall the inboard portion of the wings first

Front 22

When subsonic air flows into a diverging duct, its pressure

Back 22

increase

Front 23

On large aircraft that has two sets of ailerons each wing, only the __________ ailerons are used when the trailing edge flaps are up.

Back 23

inboard

Front 24

The basic forces that act on an aircraft in flight are

Back 24

thrust, drag, weight and lift

Front 25

Washing-in the left wing of a monoplane, for purposes of rigging corrections after flight test, will have what effect on the lift and drag of that wing?

Back 25

Both drag and lift will increase due to increased angle of attack

Front 26

When supersonic air flows into a converging duct, its density

Back 26

increase

Front 27

The dihedral angle of a wing may be measured by placing a straightedge and level protractor on the

Back 27

front spar

Front 28

When supersonic air flows into a converging duct, its pressure

Back 28

increase

Front 29

When the lift of an airfoil increases, the drag will

Back 29

also increases

Front 30

An airplane which has good longitudinal stability should have a minimum tendency to

Back 30

pitch

Front 31

The retreating blade of a helicopter will stall when the helicopter airspeed is to

Back 31

high

Front 32

When subsonic air flows into a converging duct, its density

Back 32

remains the same

Front 33

If the right wing of a monoplane is improperly rigged to a greater angle of incidence than designated in the manufacturer's specifications, it will cause the

Back 33

airplane to be off balance both laterally and directionally

Front 34

When supersonic air flows into a diverging duct, its pressure

Back 34

decreases

Front 35

When supersonic air flows into a diverging duct, its density

Back 35

decreases

Front 36

When subsonic air flows into a diverging duct, its velocity

Back 36

decreases

Front 37

The angle of incidence of an airplane

Back 37

does not change in flight

Front 38

What type of flap system increases the wing area and changes the wing camber?

Back 38

Fowler flaps

Front 39

An airplane is controlled directionally about its vertical axis by the

Back 39

rudder.

Front 40

The angle of incidence is that acute angle formed by

Back 40

a line parallel to the wing chord and a line parallel to the longitudinal axis of the aircraft.

Front 41

Parasite drag increases as the airspeed_____________.

Back 41

increases

Front 42

When subsonic air flows into a converging duct, its velocity

Back 42

increase

Front 43

When air passes through a shock wave, its velocity is ____________.

Back 43

decreased

Front 44

The purpose of wing slats is to

Back 44

reduce stalling speed

Front 45

What physical factors are involved in the aspect ratio of airplane wings?

Back 45

Span and chord

Front 46

The correct dihedral angle can be determined by

Back 46

using a dihedral board and bubble level along the front spar of each wing

Front 47

The aerodynamic load on the tail of a longitudinally stable airplane acts _____________.

Back 47

downward

Front 48

The velocity of air that has passed through a normal shock wave is

Back 48

subsonic.

Front 49

When subsonic air flows into a converging duct, its pressure

Back 49

decreases

Front 50

Dihedral is used to give an airplane _________ stability?

Back 50

lateral

Front 51

The angle of attack at which the induced and parasite drags are the same produces the ________ L/D ratio.

Back 51

maximum