This set of Aircraft Design Multiple Choice Questions & Answers (MCQs) focuses on “Wing Loading”.

1. Wing loading is ratio of ___________

a) weight of the aircraft and the reference area of wing

b) reference area of wing and power of engine

c) lift to drag

d) aerodynamic force thrust to drag

View Answer

Explanation: Wing loading is defined as the ratio of the weight of an aircraft to the reference area of wing. Similar to thrust loading, wing loading has major effects on the aircraft performance. Lift to drag ratio is defined as aerodynamic efficiency.

2. Wing loading will affect _____________

a) only stall speed

b) only ground roll

c) stall speed, climbing, ground roll etc

d) only climb

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Explanation: Ratio of the weight of an aircraft to the reference area of wing is termed as wing loading. Wing loading will show the relation between surface area and the weight of an aircraft as a whole. Wing loading will have impact on stall speed, climbing, ground roll, take-off etc.

3. Design lift coefficient is determined by wing loading.

a) True

b) False

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Explanation: Wing loading will affect the drag of aircraft. Wing loading directly affects the wetted area and span of the wing. Hence, based on adequate wing loading we can determine lift co-efficient as well.

4. Low wing loading will provide ___________

a) more space for fuel storage in wing

b) more space of fuel storage in cabin

c) less fuel storage

d) less lift

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Explanation: Wing loading will affect the size of the wing, weight of aircraft etc. Wing loading is given by, Weight off aircraft divided by reference area. If wing loading is low then, the reference area is more. This shows that large wings are used which can store more fuel.

5. As a designer I want to reduce the empty weight of my aircraft. Therefore I will ______

a) increase wing loading

b) decrease wing loading

c) wing loading has no effect

d) will reduce by exactly half

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Explanation: Wing loading is directly related to the weight of the aircraft. High wing loading refers to the small wings and vice-versa. Hence, to decrease the empty weight, we can increase the wing loading by reducing reference area.

6. An aircraft is flying with wing loading of 50 and maximum CL as 2.4. If density is 1.225 then, find the stall speed of the aircraft.

a) 5.832m/s

b) 5.823

c) 5.632m/s

d) 5.632

View Answer

Explanation: Given wing loading W/S = 50, maximum CL = 2.4, density ρ = 1.225

Now, stall speed of aircraft is given by,

Vstall = \(\sqrt{2*(\frac{W}{S})(\rho*CL)} = \sqrt{2*(50)/(1.225*2.4)} = \sqrt{34.01}\) = 5.832m/s.

7. A civil A/C has maximum lift coefficient of 3. If wing loading is 120 then, find approach speed of the aircraft. Consider sea-level density.

a) 10.5m/s

b) 10.50km/s

c) 12

d) 120

View Answer

Explanation: Given, civil aircraft, maximum CL = 3, wing loading W/S = 120

Approach speed of civil aircraft is given by,

Va = 1.3*Vstall

Where, Vstall = \(\sqrt{2*(\frac{W}{S})/(ρ*CL)}

= \sqrt{2*(120)/(1.225*3)}\) = 8.08m/s

Now, Va = 1.3*Vstall = 1.3*8.08 = 10.5m/s.

8. Determine wing loading for civil aircraft if lift-off speed is 80m/s and maximum lift coefficient is 2.8.

a) 9071.07

b) 9111

c) 911

d) 91

View Answer

Explanation: Given, a civil aircraft.

Lift off speed V1 = 80m/s, maximum lift coefficient CL=2.8.

Wing loading is given by,

W/S = 0.5*ρ*V

^{2}*CL

Where, V = V1/1.1 = 80/1.1=72.72m/s

Hence, wing loading is given by,

W/S = 0.5*ρ*V

^{2}*CL

W/S = 0.5*1.225*72.72

^{2}*2.8 = 9071.07.

9. Which of the following is correct for a jet aircraft take-off parameter (TOP)?

a) TOP = \(\frac{W/S}{σCL \frac{T}{W}}\)

b) TOP = \(\frac{1}{σCL \frac{T}{W}}\)

c) TOP = \(\frac{2}{σCL \frac{T}{W}}\)

d) TOP = \(\frac{W}{σCL \frac{T}{W}}\)

View Answer

Explanation: Take-off parameter is used to determine take-off distance for the aircraft. TOP is affected by wing loading and thrust loading both. Hence, proper estimation of such parameters are crucial. TOP for jet and prop driven will be different.

For jet, TOP = \(\frac{W/S}{σCL \frac{T}{W}}\).

10. Following graph represents __________

a) take-off distance estimation

b) take-off velocity

c) wing loading

d) power loading

View Answer

Explanation: Above diagram is representing variation of take-off parameter with take-off distance. It is used for takeoff distance estimation. Take-off parameter will vary with the wing loading and thrust loading. Power loading is ratio of power to weight for jet.

11. An aircraft has catapult end speed of 30m/s and wind over deck as 20m/s. If maximum CL is 2.6 and density is 1.22 then, find catapult wing loading.

a) 3276.859

b) 327

c) 32

d) 2

View Answer

Explanation: Given, maximum CL = 2.6, density ρ=1.22

Catapult end speed Ve = 30m/s, wind over deck Vwod = 20m/s

Now, catapult wing loading is given by,

W/S = 0.5*ρ*(Ve+Vwod)

^{2}*CL

W/S = 0.5*1.22*(30+20)

^{2}*2.6

W/s = 3276.859.

12. For prop aircraft at maximum range what will be the wing loading. Given CD0=0.02, aspect ratio as 8, e=0.6 and q=39.20Pa.

a) 21.5

b) 12.5

c) 1.05

d) 25

View Answer

Explanation: Given CD0=0.02, AR =8, e=0.6, q=39.20Pa.

For maximum range wing loading is given by,

W/S = \(q*\sqrt{\pi eARCD0} = 39.2*\sqrt{\pi*0.6*8*0.02}\) = 21.5.

13. Which of the following is correct for maximum jet range?

a) W/S = \(q*\sqrt{\pi eARCD0/3}\)

b) W/S = \(q*\sqrt{\pi eAR}\)

c) W/S = \(q*\sqrt{\pi eARCD0}\)

d) W/S = q

View Answer

Explanation: From range formula of jet aircraft maximum range is possible if aircraft is operating at wing loading W/S = \(q*\sqrt{\pi eARCD0/3}\). W/S = \(q*\sqrt{\pi eARCD0}\) is wing loading for maximum loiter performance.

14. Jet aircraft with CD=0.01+0.02CL^{2} is performing loiter. Find wing loading for maximum loiter if, AR=8.5, e=0.7 and dynamic pressure is 25Pa.

a) 10.80

b) 11.80

c) 12.80

d) 13.08

View Answer

Explanation: Given, CD = 0.01+0.2CL

^{2}, AR=8.5, e=0.7, Dynamic pressure q=25Pa.

From CD = 0.01+0.2CL

^{2}, CD0 = 0.01.

Wing loading for maximum loiter is given by,

W/S = \(q*\sqrt{\pi eARCD0}\) = W/S = 25*\(\sqrt{\pi*0.7*8.5*0.01}\) = 10.80.

15. A prop driven A/C has BHP/W as 0.08. If density ratio is 0.2 and take off lift coefficient is 3 then find take-off parameter for the aircraft. Given wing loading W/s = 35.

a) 700

b) 800

c) 900

d) 500

View Answer

Explanation: Given, a prop Aircraft.

BHP/E = 0.08, density ratio σ = 0.2, CL at take-off = 3.

Take-off parameter TOP = \(\frac{W/S}{σCL BHP/W}\) = 35 / (0.2*3*0.08) = 700.

**Sanfoundry Global Education & Learning Series – Aircraft Design.**

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