Aeroplanes, total drag, thrust + power

Question 1

Select the phase/s of flight during which wing tip vortices are likely to be present -
[a] while ever the engine is running.
[b] during the take-off run.
[c] from lift-off to touch-down.
[d] during the landing roll.

Answer 1

C

Question 2

The rate of lateral drift of vortices after they have reached ground level is closest to -
[a] 5 knots
[b] 10 knots
[c] 15 knots
[d] zero

Answer 2

A

Question 3

Select the situation which would be most likely to present the most significant wake turbulence
hazard for a light aircraft following a heavy aircraft. When the light aircraft is -
[a] flying behind and above the heavy aircraft.
[b] flying behind and at the same level as the heavy aircraft.
[c] flying behind and 900 to 1000 feet below the level of the heavy aircraft.
[d] being overtaken by the heavy aircraft.

Answer 3

C

Question 4

The minimum distance which should be allowed to avoid helicopter rotor downwash from a
heavy helicopter which is hovering is -
[a] one rotor diameter.
[b] two rotor diameters.
[c] three rotor diameters.
[d] four rotor diameters.

Answer 4

C

Question 5

Select the conditions under which a wake turbulence encounter at low level is most likely for
a light aircraft landing behind a heavy jet -
[a] dead calm conditions.
[b] a 5 knot quartering tailwind.
[c] a 15 knot headwind.
[d] a strong crosswind.

Answer 5

B

Question 6

Wake turbulence is most severe behind a heavy aircraft which -
[a] is flying slowly.
[b] is flying fast.
[c] has just touched down.
[d] is about to lift off.

Answer 6

A

Question 7

Given that one knot is about 30.5 metres per minute, the distance that vortices at ground level
would be expected to drift laterally in one minute in calm conditions would be closest to -
[a] 30.5 m.
[b] 152 m.
[c] 305 m.
[d] 500 m.

Answer 7

B

Question 8

As speed is increased from the stalling speed to maximum cruising speed in straight and level flight, the induced
drag acting on an aircraft
[a] decreases continuously [b] decreases then increases
[c] increases continuously [d] increases then decreases

Answer 8

A
Induced drag is at its greatest in level flight when speed is lowest. The more time the air has to flow around the wing tip, the stronger the vortices become.

Question 9

As speed is decreased from maximum cruising speed to stalling speed in level flight, the parasite drag acting on
an aircraft
[a] decreases continuously [b] increases continuously
[c] increases then decreases [d] decreases then increases

Answer 9

A
Parasite drag is the same as the drag you experience when riding a bicycle into wind. It gets stronger as the speed increases.

Question 10

As speed is increased from stalling speed to maximum cruising speed in level flight, the total drag acting on an
aircraft
[a] increases continuously [b] decreases continuously
[c] increases then decreases [d] decreases then increases

Answer 10

D
Total drag is high near the stall because of induced drag. It begins to decrease as speed increases. Near the middle of the speed range, total drag starts rising as parasite drag increases.

Question 11

The least amount of total drag in level flight is produced when the aircraft is flown
[a] at the slowest possible speed
[b] at a speed which produces the best lift/drag ratio
[c] at a speed which produces minimum lift
[d] at a speed which produces minimum drag coefficient

Answer 11

B
Lift is fixed in level flight- it must equal weight. The ratio between lift and drag therefore, will be greatest when drag is least.

Question 12

Design features such as high aspect ratio, wash out and taper have the effect of increasing the aircraft’s
[a] maximum speed [b] stalling speed
[c] maximum lift [d] maximum lift/drag ratio

Answer 12

D
All of these features act to decrease vortex formation by reducing the size of the wing tip, or by reducing the angle of attack at the wing tip. This results in less induced drag. If drag reduces for the same lift, the lift/drag ratio must increase.

Question 13

The greatest amount of induced drag would be produced by applying
[a] high angles of attack at high speed [b] high angles of attack at low speed
[c] low angles of attack at low speed [d] low angles of attack at high speed

Answer 13

A
Even though induced drag in level flight is highest at low speed, if high angles of attack are applied at high speed- such as in aerobatic manoeuvres, the pressure gradient increases so much that the vortices become stronger than ever.

Question 14

In level flight induced drag is
[a] directly proportional to weight and speed
[b] inversely proportional to weight and speed
[c] directly proportional to weight and inversely proportional to speed
[d] inversely proportional to weight and directly proportional to speed

Answer 14

C
In level flight, the greater the weight the greater the lift required so the greater the vortex formation. At low speed, the vortices form more readily because of the extra time available for the air to complete its journey around the wing tip.

Question 15

The speed which produces best lift/drag ratio angle of attack in level flight is also the speed which requires
[a] maximum thrust [b] minimum thrust
[c] maximum power [d] minimum power

Answer 15

B
Thrust always equals drag in level flight. Thrust will be least when drag is least. This is also the best ratio between lift and drag.

Lift is fixed in level flight- it must equal weight. The ratio between lift and drag therefore, will be greatest when drag is least.

Question 16

As the pilot raises the tail of a tail-wheel aircraft during the take-off run
[a] the tendency to swing to the left will increase
[b] there will be a tendency to swing to the right
[c] there will be no noticeable change in the tendency to swing
[d] there will be a tendency to overpitch

Answer 16

A
Gyroscopic effect will come into play, contributing to the left swing.

Question 17

The initial effect of propeller torque on a single engine aeroplane when power is increased is
[a] the aeroplane will tend to yaw to the left
[b] the aeroplane will tend to yaw to the right
[c] the aeroplane will tend to roll to the left
[d] the aeroplane will tend to roll to the right

Answer 17

C
Assuming the propeller rotates clockwise as viewed from the cockpit [as the examination will], the torque reaction will be opposite to the direction of propeller rotation. This produces a roll to the left.

Question 18

Which indicated air speed would produce maximum endurance in level flight in a piston engine aeroplane?
[a] the speed which requires minimum power
[b] the speed which requires minimum thrust
[c] the slowest possible speed
[d] the speed which produces the best lift/drag ratio

Answer 18

A
Minimum power produces minimum fuel flow. The fuel on board will last the longest time when it is used at the lowest rate. See ‘Power” on page 1.9.

Question 19

“P factor” refers to the displacement of the thrust line towards the “down going blade” side of the propeller arc.
The effect is greatest
[a] at high angles of attack with low power applied
[b] at low angles of attack with high power applied
[c] at low angles of attack with low power applied
[d] at high angles of attack with high power applied

Answer 19

D
The greater the inclination of the propeller disk to the on-coming airflow, the greater the P factor or asymmetric blade effect. This inclination is decided by the angle of attack of the aeroplane.

Question 20

Torque is that reaction which causes an aircraft to
[a] yaw in the direction of propeller rotation
[b] roll in the direction of propeller rotation
[c] roll opposite to propeller rotation
[d] yaw opposite to propeller rotation

Answer 20

C
Don’t confuse torque with slipstream. Slipstream effect causes a yaw- torque reaction causes a roll.

Question 21

If an aircraft with a clockwise propeller rotation as viewed from the cockpit has a tendency to swing to the right
during take-off, a likely cause would be
[a] slipstream effect
[b] torque effect
[c] gyroscopic effect
[d] a strong cross wind from the right

Answer 21

D
Since all other choices produce a yaw to the left- the wind would have to be the culprit.
Remember the aircraft will tend to yaw into the wind ie right for a wind from the right.

Question 22

As the tail is lifted in a tail wheel aircraft during the take-off, a pronounced swing to the left develops. This
would most likely be attributable to
[a] slipstream effect
[b] torque effect
[c] gyroscopic effect
[d] a strong cross wind from the right

Answer 22

C
Gyroscopic effect occurs as the propeller disk changes its plane of rotation. This happens when the tail is lifted during take-off.

Question 23

The application of high power with low airspeed is accompanied by
[a] engine torque producing a roll
[b] gyroscopic effect producing a roll
[c] engine torque producing a yaw
[d] slipstream effect producing a roll

Answer 23

A
The primary effect of the torque reaction is to produce a tendency to roll opposite to the direction of propeller rotation.

Question 24

For a piston engine aircraft, the maximum rate of climb possible at a given gross weight is primarily governed by
[a] the maximum lift possible
[b] the minimum drag possible
[c] excess thrust
[d] excess power

Answer 24

D
Surplus power determines the maximum rate of climb.

Question 25

If more power is required to maintain altitude when indicated air speed is reduced, the aeroplane must be flying
below
[a] Vno [maximum structural cruising speed
[b] the speed for maximum endurance speed
[c] the speed for best angle of climb
[d] the speed for minimum drag

Answer 25

B
Maximum endurance occurs at the speed which requires minimum power. Any attempt to fly a speed other than that speed [higher or lower], requires more power.

Question 26

If the indicated air speed is progressively reduced during level flight, induced drag will
[a] increase continuously as speed is decreased
[b] decrease continuously as speed is decreased
[c] increase then decrease as speed is decreased
[d] decrease then increase as speed is decreased

Answer 26

A
Induced drag is inversely proportional to speed. It gets greater as speed gets lower.

Question 27

If the approach speed of an aircraft is in the region of reverse command, a reduction in IAS will require-
[a] a higher nose attitude with no change in power required.
[b] a higher nose attitude with an increase in power required.
[c] a lower nose attitude with a decrease in power required
[d] a lower nose attitude with an increase in power required.

Answer 27

B
The region of reverse command is sometimes referred to as the ‘back of the power curve’.
Any reduction in airspeed will result in a requirement for extra power to stabilise the speed.
Without the additional power, a higher nose attitude will produce an ever decreasing airspeed to the point of stall.

Question 28

The wake turbulence gererated by a slow flying aircraft will be -
[a] greater with flaps up than with flaps down.
[b] greater with flaps down than with flaps up.
[c] the same whether the flaps are up or down.
[d] greater at high speed than at low speed.

Answer 28

A
Induced drag is the result of the pressure difference between the top and bottom of the wing
[and therefore the lift] at the tip. Flap extension causes the main lift area to move inboard
away from the wing tip. The vortices are less vigorous when the flaps are down and more
vigorous when the flaps are up.

Question 29

The phase of flight during which wing tip vorticies will always be present to some extent is -
[a] taxi and take-off run.
[b] after touch-down.
[c] from lift-off to touch-down.
[d] while ever the engine is generating thrust.

Answer 29

33