PoF

Question 1

Parasite drag =

Answer 1

Skin friction drag + form drag + interference drag

Question 2

Profile drag =

Answer 2

Skin friction drag + form drag

Question 3

Skin friction drag =

Answer 3

Airflow causing friction over the wing

Question 4

What worsens skin friction drag

Answer 4

Wing contamination

Question 5

Form drag =

Answer 5

Pressure differential between leading & trailing edge (pressure at leading edge higher than trailing)
Aerodynamic force of high to low PG acts against direction of flight

Question 6

Is Q (IAS) proportional to form drag

Answer 6

Yes

Question 7

What happens to form drag when:
1) AOA increases?
2) Vortex generators are installed?

Answer 7

1) form drag increases
2) form drag decreases

Question 8

How to minimise parasite drag? (4)

Answer 8

• Streamlining
• Incorporating fillets & fairings
• Using laminar flow wing sections
• Minimising frontal area

Question 9

Induced drag =

Answer 9

Span-wise flow causing wing tip vortices

Question 10

Higher CL or lower IAS affects Induced drag how?

Answer 10

Stronger wing tip vortices

Question 11

What do wing tip vortices cause?

Answer 11

Stronger downwash = rearward inclined wing lift = greater induced drag

Question 12

What happens to induced drag when:
1) lift increases?
2) weight increases?
3) load factor (g) increases?
4) speed increases?
5) aspect ratio increases?

Answer 12

1) induced drag increases
2) induced drag increases
3) induced drag increases
4) induced drag decreases
5) induced drag decreases

Question 13

What is the CDi equation?

Answer 13

CDi = CL² ÷ AR

Question 14

How to minimise induced drag? (3)

Answer 14

• High AR
• Tapered wing Planform with wing twist & span-wise camber variation
• Using end plates, tip-tanks, winglets or tip shaping

Question 15

Gravity =

Answer 15

9.81 m/s²

Question 16

Is air density proportional to TAS?

Answer 16

No (inversely proportional)

Question 17

What happens to air density when:
1) Temp. increases?
2) Static pressure increases?
3) Humidity increases?
4) Alt. increases?

Answer 17

1) air density decreases
2) air density increases
3) air density decreases
4) air density decreases

Question 18

A plane is rolling right, which aileron is down?

Answer 18

Left aileron down

Question 19

What camber does the horizontal stabiliser have?

Answer 19

Negative

Question 20

1 metre = how many ft?

Answer 20

3.28ft

Question 21

How many ft in a statue mile?

Answer 21

5280ft

Question 22

How many ft in a NM?

Answer 22

6080ft

Question 23

How many kts per m/s?

Answer 23

2

Question 24

How to calculate °Kelvin?

Answer 24

°C + 273

Question 25

How to calculate °F?

Answer 25

(⁹/⁵ × °C) + 32

Question 26

How many lbs in a kg?

Answer 26

2.205

Question 27

What is the sweep angle?

Answer 27

Angle between the 25% chord line & the line perpendicular to the root chord

Question 28

What happens when entering ground effect?

Answer 28

- Lift increases - Induced drag decreases - Tailplane æ modified so that less downforce is created = pitch down moment - ASI & altimeter under-read

Question 29

Where is the AC on a wing?

Answer 29

¼ chord position at < Mach 0.4

Question 30

Taper ratio =

Answer 30

Tip chord ÷ root chord

Question 31

Mean geometric chord =

Answer 31

Wing area ÷ wing span

Question 32

Aspect ratio =

Answer 32

Wing span ² ÷ wing area

Question 33

Lift equation?

Answer 33

L = ½ p V² S CL

Question 34

Lift equation where CL is sought?

Answer 34

CL = L ÷ (½ p V² S)

Question 35

Dynamic pressure=

Answer 35

½ p V²

Question 36

What is the relationship between IAS & dynamic pressure?

Answer 36

IAS is proportional to √dynamic pressure

Question 37

CLMAX =

Answer 37

1 ÷ Vs²

Question 38

VS1g (new) =

Answer 38

VS1g (old) × √(new weight ÷ old weight)

Question 39

New VA ÷ old VA =

Answer 39

√CL old ÷ CL new

Question 40

What's the relationship between new and old load factors (n) and old and new speeds (V)

Answer 40

N(new) ÷ n(old) proportional to V²new ÷ V²old

Question 41

Load factor (n) =

Answer 41

Lift ÷ Weight

Question 42

n∆ =

Answer 42

Vnew² ÷ Vold²

Question 43

Bernoulli's theorem =

Answer 43

P + ½ p V² = K Pressure + kinetic energy (dynamic pressure) = constant

Question 44

Pressure (Pa) =

Answer 44

Force (N) ÷ Area (m²)

Question 45

Lift & drag depend on? (4)

Answer 45

- AoA - Aerofoil thickness & camber - Air density - Velocity

Question 46

What is the best L/D ratio known as?

Answer 46

Optimum AoA

Question 47

Will a change of weight in a given config. change L/D max?

Answer 47

No

Question 48

An AoA other than optimum AoA will cause what with regards to the L/D ratio?

Answer 48

More drag for lift required

Question 49

Mach No. =

Answer 49

TAS ÷ LSS

Question 50

LSS =

Answer 50

38.96 × √absokute temp. (K)

Question 51

Thrust =

Answer 51

T = D + W sin(gamma) D = drag, W = weight, Gamma = angle between weight & opposite to lift in a climb

Question 52

Limit load factors: 1) CS-25? 2) Normal CS-23? 3) Utility CS-23? 4) Aerobatic CS-23?

Answer 52

1) -1g to +2.5g 2) -1.52g to +3.8g 3) -1.76g to +4.4g 4) -3g to +6g