pt pof alpha

Question 1

one important advantage the turbulent boundary layer has over the laminar layer is that:

a. it is less tendency to separate from the surface

b. it is thinner

c. energy is less

d. skin friction is less

Answer 1

a. it is less tendency to separate from the surface

Question 2

what happens to (1) total pressure and (2) static pressure in the converging section of a Venturi?

a. (1) decreases (2) increases

b. (1) increases (2) decreases

c. (1) remains constant (2) increases

d. (1) remains constant (2) decreases

Answer 2

d. (1) remains constant (2) decreases

Question 3

What causes form drag?

a. airflows joining at different speeds and directions at airframe junctions.

b. pressure differences in front and behind an object.

c. vortices at tip and trailing edge of wings.

d. shear forces within the boundary layer.

Answer 3

b. pressure differences in front and behind an object.

Question 4

In two dimensional flow the angle of attack is defined as the angel between the…

a. the relative airflow and the chord line

b. relative airflow and the horizontal.

c. relative airflow and the longitudinal axis.

d. effective airflow and the chord line.

Answer 4

a. the relative airflow and the chord line

Question 5

what is the below statements relating to the coefficient of lift is true?

a. CL is inversely proportional to IAS4

b. CL is inversely proportional to IAS

c. CL is proportional to 1/IAS2

d. CL is proportional to IAS2.

Answer 5

c. CL is proportional to 1/IAS2

Question 6

slats:

a. increase CL at a given speed and should be extended last on approach.

b. increase camber and CLmax

c. do not increase camber and should be retracted last after take off.

d. decrease the CL at a given speed when retracted.

Answer 6

b. increase camber and CLmax

Question 7

straight and level flight q

Question 8

The point span wise that a moderately tapered wing stalls first is the [ ]. This is where the downwash is [ ]the effectiveness airflow is the [ ] and the effective AoA is [ ].

Answer 8

[tip]
[greatest]
[shallowest]
[greatest]

Question 9

In straight and level flight an aircraft has a stall speed of 72kts. If the aircraft enters a turn with a load factor of 2.3, what is the new stall speed?

please give your numerical answer to 3 significant figures.

answer is assumed to be in knots.

Answer 9

109

Question 10

Considering three dimensional flow about a wing, which of the below statements is true?

a. the low pressure air below the wing moves towards the high pressure air on top of the wing via the wing tips.

b. the flow is clockwise about the left wing tip when viewed from behind.

c. the high pressure air on top of the wing moves towards the low pressure air below the wing via the wing tips.

d. the flow is from the tip towards the root below the wing.

Answer 10

b. the flow is clockwise about the left wing tip when viewed from behind.

Question 11

An aircraft in straight and level flight with a lift force of 1,468,800N if flying at a TAS of 259kts. The aircraft has a surface area of 330m2. The air density is 0.825kg/m3.

What is the CL of the aircraft? (please give your answer to 2 decimal places)

Answer 11

0.61

Question 12

The aircraft drag in straight and level is least when the:

a. induced drag squared equals the square root of parasite drag.

b. induced drag is least.

c. parasite drag is equal to the induced drag.

d. parasite drag squared equals the square root of induced drag.

Answer 12

c. parasite drag is equal to the induced drag.

Question 13

Entering ground effect, the downwash ………….. causing the effective angle of attack to …………… and the aeroplane to ……………..

a. decreases, increase, balloon.

b. decreases, decrease, float.

c. increases, decrease, stall.

d. decreases, increase, stall AOA increases.

Answer 13

b. decreases, decrease, float.

Question 14

new stall speed q

Question 15

stall speed increases when the aeroplane

1. mass [ ]
2. centre of gravity [ ]
3. is [ ]
4. flaps are [ ]
5. leading edge of the wing [ ].

Answer 15

[is greater]
[moves forward]
[turning]
[retracted]
[is contaminated]

Question 16

A straight wing, light aircraft is flying straight and level. if the aircraft enters the stall, which of the following conditions are likely to be true?

PICK 3 of 5

a. buffet is felt.
b. a rate of descent is observed.
c. aural indication inside the cockpit.
d. the controls become more effective.
e. uncommanded pitch up

Answer 16

a. buffet is felt.

c. aural indication inside the cockpit.

e. uncommanded pitch up

Question 17

Comparing a trimmable horizontal stabiliser and an elevator trim tab, which of the statements are respectively correct or incorrect?

i. when trimmed for zero elevator stick force an elevator trim tab creates more drag.

ii. an elevator trim tab enables a larger CG range.

a. (i) correct (ii) incorrect
b. (i) incorrect (ii) incorrect
c. (i) correct (ii) correct
d. (i) incorrect (ii) correct

Answer 17

d. (i) incorrect (ii) correct

Question 18

which of the following describes a device that counteracts adverse yaw?

a. frise ailerons, where due to shape the nose aileron protrudes into the airflow on downgoing aileron.

b. differential ailerons, where the ailerons on the downing wing moves through a larger angle.

c. differential ailerons, where the nose of the upping aileron protrudes into the airflow causing more drag.

d. an anti-balance tab, which increases the drag on the upgoing wing.

Answer 18

a. frise ailerons, where due to shape the nose aileron protrudes into the airflow on downgoing aileron.

Question 19

Interference and induced drag can be reduced at the aeroplane the design phase by:

a. a smooth surface and sharklets respectively.

b. a smooth surface and streamlining.

c. streamlining and winglets respectively.

d. fillets and high aspect ratio respectively.

Answer 19

d. fillets and high aspect ratio respectively.

Question 20

The pilot pitches the aircraft about the [ ] axis using the [ ].

Answer 20

the pilot pitches the aircraft about the [lateral] axis using the [elevator].

Question 21

A design which increases the control load on a pilot is called:

a. an anti-balance tab
b. a mass balance
c. a horn balance
d. an internal balance.

Answer 21

a. an anti-balance tab

Question 22

Please select all characteristics of laminar flow.

a. high energy close to the base.
b. 2-3cm deep
c. low energy close to the base.
d. greater skin friction drag.
e. more prone to separation.
f. less prone to separation.
g. 2-3mm deep
h. shallow velocity gradient.
i. lower skin friction drag.
j. steep velocity gradient.

Answer 22

a. high energy close to the base.
d. greater skin friction drag.
e. more prone to separation.
g. 2-3mm deep
j. steep velocity gradient.

Question 23

Consider a CL - alpha graph. if all other factors remain the same a higher aspect ratio wing results in

a. an increase in stalling angle of attack.

b. a decrease in the stalling angle of attack.

c. a decrease in CLmax

d. an increase in CLmax

Answer 23

d. an increase in CLmax

Question 24

To recover from a fully developed spin the pilot should { } determine [ ] and then use ( ). Move the control column
| |. When the spin stops the pilot should [ ].

Answer 24

{close the throttle}
[direction of spin]
(opposite rudder)
|centrally forward|
[roll wings level and then pitch up].