Aircraft Design MCQ – Wing Loading
1 - Question
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
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 - Question
Wing loading will affect _____________
a) only stall speed
b) only ground roll
c) stall speed, climbing, ground roll etc
d) only climb
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 - Question
Design lift coefficient is determined by wing loading.
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 - Question
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
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 - Question
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
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 - Question
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.
Explanation: Given wing loading W/S = 50, maximum CL = 2.4, density ρ = 1.225 Now, stall speed of aircraft is given by, Vstall = 2∗(WS)(ρ∗CL)−−−−−−−−−−−−−√=2∗(50)/(1.225∗2.4)−−−−−−−−−−−−−−−−√=34.01−−−−√ = 5.832m/s.
7 - Question
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.
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 = 2∗(WS)/(ρ∗CL)−−−−−−−−−−−−−−√=2∗(120)/(1.225∗3)−−−−−−−−−−−−−−−−√ = 8.08m/s Now, Va = 1.3*Vstall = 1.3*8.08 = 10.5m/s.
8 - Question
Determine wing loading for civil aircraft if lift-off speed is 80m/s and maximum lift coefficient is 2.8.
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*V2*CL Where, V = V1/1.1 = 80/1.1=72.72m/s Hence, wing loading is given by, W/S = 0.5*ρ*V2*CL W/S = 0.5*1.225*72.722*2.8 = 9071.07.
9 - Question
Which of the following is correct for a jet aircraft take-off parameter (TOP)?
a) TOP = W/SσCLTW
b) TOP = 1σCLTW
c) TOP = 2σCLTW
d) TOP = WσCLTW
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 = W/SσCLTW.
10 - Question
Following graph represents __________
a) take-off distance estimation
b) take-off velocity
c) wing loading
d) power loading
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 - Question
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.
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 - Question
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.
Explanation: Given CD0=0.02, AR =8, e=0.6, q=39.20Pa. For maximum range wing loading is given by, W/S = q∗πeARCD0−−−−−−−−−√=39.2∗π∗0.6∗8∗0.02−−−−−−−−−−−−−√ = 21.5.
13 - Question
Which of the following is correct for maximum jet range?
a) W/S = q∗πeARCD0/3−−−−−−−−−−√
b) W/S = q∗πeAR−−−−−√
c) W/S = q∗πeARCD0−−−−−−−−−√
d) W/S = q
Explanation: From range formula of jet aircraft maximum range is possible if aircraft is operating at wing loading W/S = q∗πeARCD0/3−−−−−−−−−−√. W/S = q∗πeARCD0−−−−−−−−−√ is wing loading for maximum loiter performance.
14 - Question
Jet aircraft with CD=0.01+0.02CL2 is performing loiter. Find wing loading for maximum loiter if, AR=8.5, e=0.7 and dynamic pressure is 25Pa.
Explanation: Given, CD = 0.01+0.2CL2, AR=8.5, e=0.7, Dynamic pressure q=25Pa. From CD = 0.01+0.2CL2, CD0 = 0.01. Wing loading for maximum loiter is given by, W/S = q∗πeARCD0−−−−−−−−−√ = W/S = 25*π∗0.7∗8.5∗0.01−−−−−−−−−−−−−−√ = 10.80.
15 - Question
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.
Explanation: Given, a prop Aircraft. BHP/E = 0.08, density ratio σ = 0.2, CL at take-off = 3. Take-off parameter TOP = W/SσCLBHP/W = 35 / (0.2*3*0.08) = 700.