46 + Interview Questions in Aerodynamics in Aircraft Design Page 1 InterviewSolution

1.	Aerodynamic forces are generated due to ______________(a) shear and pressure force acting on body(b) shear effects only(c) only pressure forces(d) twisting of beamThe question was asked in exam.My doubt stems from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design
Answer» CORRECT choice is (a) SHEAR and pressure force acting on body To EXPLAIN I WOULD say: Shear force and pressure force are most fundamental cause which generates aerodynamic forces. Shear forces typically seen as resisting forces which results in friction. Pressure force or pressure GRADIENT will generate forces as well.

Discussion

2.	For ideal flow, total pressure along streamline will be _________(a) constant(b) increases(c) decreases(d) always decreases by halfThis question was posed to me in class test.I would like to ask this question from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design
Answer» Correct answer is (a) constant Explanation: Bernoulli’s theorem is one of the fundamental principles in fluid dynamics and mechanics. It STATS TOTAL PRESSURE along streamline will be constant. Total pressure is sum of static pressure and DYNAMIC pressure.

Discussion

3.	Increment in the skin friction drag due to prop-wash is called _________(a) scrubbing drag(b) vortex(c) swirl(d) curling flowThe question was asked during an online interview.Asked question is from Aerodynamic Forces in portion Aerodynamics of Aircraft Design
Answer» CORRECT answer is (a) scrubbing drag The BEST I can explain: Scrubbing drag is drag produced due to Increment in skin friction drag as a result of prop WASH. Vortex is produced due to PRESSURE difference. Swirling is nothing but the turning of flow. Curling of flow can be SEEN as change in direction of flow.

Discussion

4.	If static air pressure is 0.5 bar and dynamic pressure is 0.85 bar then, find total pressure acting on a body.(a) 1.35(b) 5(c) 7(d) 8.56I had been asked this question by my school principal while I was bunking the class.My doubt stems from Aerodynamic Forces topic in section Aerodynamics of Aircraft Design
Answer» Correct choice is (a) 1.35 Explanation: TOTAL PRESSURE = STATIC pressure + DYNAMIC pressure = 0.5 + 0.85 = 1.35 BAR.

Discussion

5.	Consider an incompressible flow. If static pressure increases then, the local freestream velocity __________(a) decreases(b) increase(c) remains same(d) insufficient dataI had been asked this question during a job interview.Query is from Aerodynamic Forces topic in portion Aerodynamics of Aircraft Design
Answer» Correct option is (a) decreases To explain I WOULD SAY: If static pressure is increased then the corresponding value of the dynamic pressure should decrease. BERNOULLI’s has provided BETTER understanding of pressure ACTING on the aircraft.

Discussion

6.	For an incompressible flow, if local area velocity decreases then, the dynamic pressure will ________(a) decrease(b) increase(c) constant(d) independent of velocityThis question was posed to me in final exam.I'd like to ask this question from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design
Answer» The CORRECT option is (a) decrease To explain: DYNAMIC pressure is defined as the product of DENSITY and square of velocity and 0.5. It is pressure exerted by fluid due to motion and the fluid flow. As MENTIONED, dynamic pressure is proportional to square of velocity and hence, if velocity decreases then, the value of corresponding dynamic pressure is reduced as WELL.

Discussion

7.	Skin friction drag is defined as _________(a) drag due to friction between skin and fluid flow(b) wing lift drag(c) such drag does not exist(d) lift inducedThe question was asked in quiz.I need to ask this question from Aerodynamic Forces in chapter Aerodynamics of Aircraft Design
Answer» The correct ANSWER is (a) drag due to friction between skin and fluid flow The explanation is: Skin friction drag is defined as drag caused by the friction between fluid flow and the skin of an object. Skin friction can lead to aerodynamic heating phenomena. Wing lift drag is AFFECTED by the lift PRODUCED. Lift induced drag is drag which is Induced due to wing lift in FINITE wing.

Discussion

8.	Following diagram represents __________(a) plain flap(b) aileron(c) rudder(d) spoilerThe question was asked in exam.My question is taken from Aerodynamics in section Aerodynamics of Aircraft Design
Answer» Correct answer is (a) plain flap Best explanation: Flap is a high lift device. Flap is used to increase lift PRODUCED by wing during landing and TAKEOFF. Aileron is used to bank the AIRCRAFT. Rudder provides yawing motion to the aircraft. Spoiler is used to provide additional drag during landing.

Discussion

9.	_______ is one of the sources of drag.(a) Viscous separation(b) Drafting(c) Signal strength(d) Lift onlyThis question was posed to me in an online quiz.This interesting question is from Aerodynamic Forces in chapter Aerodynamics of Aircraft Design
Answer» Correct answer is (a) Viscous separation The explanation is: Viscous separation is ONE of the major factor of the drag GENERATION. DRAFTING is concerned with DRAWING. Signal strength is affected by distance between SOURCE and target. Lift only is not source of drag. Lift is responsible for lift induced drag.

Discussion

10.	For a symmetrical airfoil drag coefficient at zero lift is 0.05 and induced drag coefficient is 0.0025. Find the total drag coefficient.(a) 0.0525(b) 0.45(c) 5.25(d) 52.5This question was addressed to me in unit test.I need to ask this question from Aerodynamic Coefficients in division Aerodynamics of Aircraft Design
Answer» The correct option is (a) 0.0525 The BEST EXPLANATION: Total drag COEFFICIENT = drag coefficient at ZERO lift + induced drag coefficient = 0.05+0.0025 = 0.0525.

Discussion

11.	The change in local air flow velocity will produce small change in skin friction drag.(a) True(b) FalseThe question was asked in an online interview.My question is from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design
Answer» Right option is (a) True To elaborate: As the LIFT on the wing changes, the corresponding value of velocity at upper and lower SURFACE will also change. This change in local flow velocity will produce small change at skin friction DRAG. This EFFECT is called ‘super velocity’ effect.

Discussion

12.	Following diagram represents ___________(a) uncambered wing lift curve(b) cambered airfoil lift curve(c) cambered wing lift curve slope(d) uncambered airfoilI got this question at a job interview.My question comes from Aerodynamics in portion Aerodynamics of Aircraft Design
Answer» Right choice is (a) uncambered wing LIFT curve The BEST explanation: A typical diagram of lift curve is illustrated in above figure. The diagram is APPLICABLE to uncambered wing. Airfoil lift curve will be different from wing. Typically, lift coefficient of airfoil is GREATER than the wing.

Discussion

13.	Following diagram represents _______________(a) cambered wing lift curve(b) drag polar(c) thrust loading(d) power loadingI had been asked this question during an interview for a job.This interesting question is from Aerodynamics in division Aerodynamics of Aircraft Design
Answer» Correct answer is (a) cambered wing lift curve Explanation: A typical, lift curve is shown for Cambered airfoil. As shown in the diagram, camber wing with cambered airfoils will produce lift at SMALL angle. Drag POLAR is used to provide INFORMATION about drag characteristics. THRUST LOADING is defined as ratio of weight to thrust.

Discussion

14.	A supersonic 2D airfoil has Mach number of 1.5. Find Lift curve slope of the airfoil.(a) 0.062 per degree(b) 0.062 per rad(c) 24 per degree(d) 12.56 per degreeI have been asked this question in quiz.I'm obligated to ask this question of Aerodynamics in portion Aerodynamics of Aircraft Design
Answer» CORRECT OPTION is (a) 0.062 per degree The best explanation: Given, MACH number M = 1.5 2D lift curve slope = 4 / (M^2 – 1)^0.5 = 4 / (1.5^2 – 1)^0.5 = 3.57 per RAD = 3.57/57.3 = 0.062 per degree.

Discussion

15.	If an aircraft is operating with dynamic pressure of the free stream q=20Pa and has area of wing is 10m^2 then evaluate drag experience by the aircraft. Given drag coefficient is 0.9.(a) 180 N(b) 345 N(c) 234 N(d) 567 NI have been asked this question at a job interview.Query is from Aerodynamic Coefficients in portion Aerodynamics of Aircraft Design
Answer» The CORRECT answer is (a) 180 N Easiest explanation: Given, FREE STREAM q=20Pa, AREA of wing S = 10m^2, drag coefficient CD = 0.9 Drag D = qSCD = 20100.9 = 180N.

Discussion

16.	Following diagram represents ______________(a) cambered wing drag polar(b) cambered airfoil drag polar(c) symmetric wing drag polar(d) drag polar of an airfoilThis question was posed to me during an online exam.My doubt stems from Aerodynamic Coefficients in division Aerodynamics of Aircraft Design
Answer» Right ANSWER is (a) CAMBERED wing drag polar Best explanation: Above diagram is showing typical drag polar for cambered wing. Drag polar will be DIFFERENT for different types of wing. Drag polar is graphical representation of drag CHARACTERISTICS. It shows relationship between drag coefficient and lift coefficient TYPICALLY.

Discussion

17.	Find the approximate value of wetted area Swet for given reference area of Sref=20 unit and parasite drag coefficient of 0.0028. Consider equivalent skin friction coefficient Cf as 0.003.(a) 18.67 unit(b) 12 unit(c) 20 unit(d) 65 unitI got this question in semester exam.My question is from Aerodynamics topic in section Aerodynamics of Aircraft Design
Answer» RIGHT CHOICE is (a) 18.67 UNIT The explanation: Wetted area SWET = Parasite DRAG coefficientSref/Cf = 0.002820/0.003 = 18.67 unit.

Discussion

18.	Drag which is produced due to lift is called?(a) Induced drag(b) Parasite drag(c) Weight(d) Thrust dragThis question was addressed to me at a job interview.The doubt is from Aerodynamic Forces topic in chapter Aerodynamics of Aircraft Design
Answer» CORRECT option is (a) Induced drag Easy explanation: Drag which is PRODUCED due to lift is called lift induced or simply induced drag. Induced drag is generated due to downwash phenomena. This downwash induces an additional FORCE component which is acting in the opposite direction of the aircraft forward MOTION. This induced force is called induced drag or lift induces drag.

Discussion

19.	Cambered wing has minimum drag coefficient of 0.05 and constant K of 0.023. If CL is 0.8 then find the value of CD. Given minimum drag occurs at CL of 0.1.(a) 0.06127(b) 6.1(c) 61.2(d) 0.6721The question was posed to me in class test.The query is from Aerodynamic Coefficients topic in chapter Aerodynamics of Aircraft Design
Answer» Right CHOICE is (a) 0.06127 To elaborate: Given, minimum drag COEFFICIENT CDmin = 0.05, constant K of 0.023, CL is 0.8 and minimum drag OCCURS at CL of 0.1. Hence, CLmindrag = 0.1. Now, CD is given by, CD = CDmin + K(CL – CLmindrag)^2 = 0.05+0.023(0.8-0.1)^2 = 0.06127.

Discussion

20.	Equivalent skin friction coefficient can be used to provide initial estimation of the parasite drag.(a) True(b) FalseI got this question in an internship interview.This interesting question is from Aerodynamics topic in portion Aerodynamics of Aircraft Design
Answer» Right CHOICE is (a) True The explanation is: Yes, it is true. Equivalent SKIN friction coefficient can be used to provide INFORMATION about the initial estimation of parasite drag. In this method, we estimate the parasite drag based on equivalent skin friction coefficient and WETTED area of the aircraft.

Discussion

21.	The location of separation point will depend on ________(a) curvature of the body(b) body weight(c) mass of body(d) only on body lengthThis question was addressed to me in examination.My question is taken from Aerodynamic Forces in portion Aerodynamics of Aircraft Design
Answer» The correct OPTION is (a) CURVATURE of the body The BEST I can EXPLAIN: Curvature of the body will affect the LOCATION of separation point.

Discussion

22.	If an airfoil is designed to provide lift curve slope as 7.8, then find airfoil efficiency. The actual lift curve slope of the airfoil is 7.4.(a) 94.87%(b) 45%(c) 15.6%(d) 98.7%The question was posed to me by my college director while I was bunking the class.My question is taken from Aerodynamics topic in portion Aerodynamics of Aircraft Design
Answer» The correct answer is (a) 94.87% Explanation: AIRFOIL efficiency = Actual LIFT CURVE slope / theoretical or designed lift curve slope = 7.4/7.8 = 0.9487 = 94.87%.

Discussion

23.	Which of the following is a method for estimating the potato drag?(a) Equivalent skin friction method(b) Mach number(c) Weight only(d) Conceptual designThe question was posed to me in examination.The question is from Aerodynamics topic in chapter Aerodynamics of Aircraft Design
Answer» The correct answer is (a) Equivalent skin friction method For EXPLANATION: Equivalent skin friction method is one of the typical method used to estimate PARASITE DRAG. Mach number is defined as the ratio of the speed of object to the speed of SOUND. Weight is force due to gravity.

Discussion

24.	Following diagram represents _____________(a) typical drag polar(b) drag polar for non-symmetric wing(c) wing lift curve(d) thrust required for wingThis question was addressed to me in an interview.I'd like to ask this question from Aerodynamic Coefficients in chapter Aerodynamics of Aircraft Design
Answer» Right option is (a) TYPICAL DRAG polar Easy explanation: The above diagram is illustrating a typical schematic diagram of airfoil drag polar. Drag polar is nothing but a graph which SHOWS variation of drag coefficient with respect to lift coefficient. Wing lift CURVE is used to SHOW lift variation.

Discussion

25.	A subsonic aircraft wing has aspect ratio of 8. Now we have been asked to provide winglet to this wing. Evaluate approximate value of effective aspect ratio of winglet is considered.(a) 9.6(b) 23(c) 32(d) 4.89I have been asked this question in class test.This intriguing question originated from Aerodynamics topic in division Aerodynamics of Aircraft Design
Answer» The CORRECT CHOICE is (a) 9.6 Easiest EXPLANATION: APPROXIMATE effective aspect RATIO = 1.2Wing aspect ratio = 1.28 = 9.6.

Discussion

26.	A wing is designed to operate with free stream velocity of 20m/s and air density of 1.225 kg/m^3. Find aerodynamic efficiency of given wing. Consider S as 8 m^2, CL as 0.9 and CD as 1.25.(a) 0.72(b) 2(c) 3(d) 5.23This question was addressed to me in examination.Question is from Aerodynamic Coefficients in section Aerodynamics of Aircraft Design
Answer» The correct ANSWER is (a) 0.72 The BEST explanation: Given, CL = 0.9, CD = 1.25 Aerodynamic efficiency is DEFINED as the RATIO of CL and CD of the aircraft. Hence, Aerodynamic efficiency = CL/CD = 0.9/1.25 = 0.72.

Discussion

27.	To get initial estimation of the parasite drag, aircraft wetted area can be multiplied by _____(a) equivalent skin friction coefficient(b) weight(c) lift(d) wing spanThe question was posed to me in class test.Question is taken from Aerodynamics in division Aerodynamics of Aircraft Design
Answer» The correct choice is (a) equivalent SKIN friction coefficient Best EXPLANATION: Initial ESTIMATION of parasite drag can be obtained by multiplying equivalent skin friction coefficient with wetted area of aircraft. Lift and WEIGHT will be in opposite direction to each other. WING span is a typically length of the aircraft.

Discussion

28.	What is interference drag?(a) Drag produced by interaction of different components(b) Skin friction drag(c) Lift induced drag(d) Drag due to weight of the aircraft onlyThe question was asked in an interview for internship.Query is from Aerodynamic Forces topic in section Aerodynamics of Aircraft Design
Answer» Correct choice is (a) Drag produced by interaction of different COMPONENTS For EXPLANATION I would say: Drag produced due to interaction between various components is termed as interference drag. Skin friction drag is due to VISCOSITY effects. Skin friction is one of the parameters which affects aerodynamic heating. Lift induced drag is RESULT of vortices and downwash.

Discussion

29.	A 2D airfoil is operating at 0.6M. Find the approximate value of lift curve slope in per rad.(a) 7.85(b) 1.9(c) 2.3(d) 3.87I got this question during an internship interview.This interesting question is from Aerodynamics in portion Aerodynamics of Aircraft Design
Answer» CORRECT option is (a) 7.85 Easiest explanation: Given, MACH number M = 0.6 2D LIFT curve slope = 2π / (1-M^2)^0.5 = 2π / (1-0.6^2)^0.5 = 7.85 per RAD.

Discussion

30.	Which of the following is correct for nacelle form factor (FF)?(a) FF = 1+(0.35/f)(b) FF = 1*(0.35/f)(c) FF = 1-(0.35/f)(d) FF = 1/(0.35/f)The question was posed to me during an interview.Query is from Aerodynamics in portion Aerodynamics of Aircraft Design
Answer» The correct option is (a) FF = 1+(0.35/f) BEST EXPLANATION: Form factor will be different for different components of an AIRCRAFT. For nacelle, form factor can be estimated as follows: Form factor FF = 1 + (0.35/f). Where, f = length/maximum DIAMETER = fineness RATIO.

Discussion

31.	If an aircraft as pitching moment of 10 Nm and dynamic pitching moment is about 8.25Nm. Find the moment coefficient Cm.(a) 1.21(b) 3(c) 5.62(d) 0.0921The question was posed to me in quiz.The origin of the question is Aerodynamic Coefficients in division Aerodynamics of Aircraft Design
Answer» RIGHT option is (a) 1.21 To ELABORATE: Moment coefficient Cm = PITCHING moment / DYNAMIC pitching moment Cm = 10/8.25 = 1.21.

Discussion

32.	Equivalent skin friction coefficient may include ______________(a) skin friction and separation drag(b) only wave drag(c) only skin friction drag(d) only thrust loadingI got this question in homework.My query is from Aerodynamics topic in division Aerodynamics of Aircraft Design
Answer» Correct ANSWER is (a) skin friction and separation drag The explanation is: Equivalent skin friction COEFFICIENT includes both skin friction and separation drag. WAVE drag is supersonic PHENOMENON. Wave drag occurs when aircraft is traveling with speeds greater than the speed of sound. Thrust loading is DEFINED as the ratio of the thrust and weight.

Discussion

33.	Determine the initial estimation of parasite drag coefficient if, equivalent skin friction coefficient is 0.004 and ratio of wetted area to the reference area is 0.8.(a) 0.0032(b) 1.2(c) 4.2(d) 0.04The question was asked in an international level competition.My question is taken from Aerodynamics topic in chapter Aerodynamics of Aircraft Design
Answer» RIGHT option is (a) 0.0032 The BEST explanation: Parasite DRAG coefficient = equivalent skin friction coefficientarea RATIO = 0.0040.8 = 0.0032.

Discussion

34.	How do you define the lift coefficient?(a) Ratio of aerodynamic lift to the dynamic lift(b) Lift to drag(c) Wing lift to weight of aircraft(d) Thrust to weightThe question was asked during an internship interview.This intriguing question comes from Aerodynamic Coefficients in portion Aerodynamics of Aircraft Design
Answer» The correct ANSWER is (a) Ratio of aerodynamic lift to the dynamic lift Easy explanation: Lift coefficient is defined as aerodynamic lift divided by Dynamic lift. Dynamic lift is defined as product of dynamic PRESSURE and REFERENCE AREA. Lift coefficient of airfoil and wing will be different.

Discussion

35.	Induced drag of the airfoil is _____(a) 0.0N(b) 1.2N(c) 20 N(d) 25.8KNThis question was addressed to me in semester exam.This intriguing question originated from Aerodynamic Forces in section Aerodynamics of Aircraft Design
Answer» The CORRECT option is (a) 0.0N The explanation is: GIVEN, an airfoil Airfoil has infinitely long span. Now, INDUCED drag coefficient is given by, Cdi = SCl^2/πeB2 = SCl^2 / πe∞ = 0 N.

Discussion

36.	If I want to design an aircraft which primary flies in a low speed region then, which type of drag shouldn’t be considered?(a) Wave drag(b) Parasite drag(c) Induced drag(d) Form drag onlyI got this question in an interview.I want to ask this question from Aerodynamic Forces in chapter Aerodynamics of Aircraft Design
Answer» Right CHOICE is (a) Wave drag To elaborate: Wave drag is drag produced at HIGH speeds. At SUPERSONIC or near supersonic SPEED due to shock formation, the wave drag is produced. Hence, for low speed AIRCRAFTS, the wave drag is not a key parameter.

Discussion

37.	At same value of maximum lift AOA, lift coefficient of Cambered wing is _________(a) higher than uncambered wing(b) lower than uncambered wing(c) same as cambered airfoil always(d) not dependent on camberI got this question in unit test.This interesting question is from Aerodynamics in chapter Aerodynamics of Aircraft Design
Answer» CORRECT answer is (a) higher than uncambered WING The explanation: Lift coefficient at maximum lift AOA for a cambered wing is higher than that of the uncambered wing. At maximum lift AOA, value of lift coefficient will be maximum as well. Further INCREASE in angle will REDUCE the amount of lift generated by wing.

Discussion

38.	Wave drag is produced due to ________(a) shock wave formation(b) incompressible flow(c) fluid is not compressible(d) flow separation of incompressible flowI had been asked this question in exam.Asked question is from Aerodynamic Forces in section Aerodynamics of Aircraft Design
Answer» Correct answer is (a) shock WAVE formation The best I can EXPLAIN: Wave drag is primarily result of shock wave formation. Shock waves are very thin layer across which we can observe DRASTIC change in the FLOW properties. Across shock, PRESSURE and temperature will increase drastically. This sudden change in pressure results in the wave drag.

Discussion

39.	Which of the following is correct?(a) D = qSCD(b) D = qSCDρ(c) D = qCD(d) D = qI have been asked this question in my homework.The origin of the question is Aerodynamic Coefficients in division Aerodynamics of Aircraft Design
Answer» Right choice is (a) D = qSCD To EXPLAIN: Above equation is a general equation of drag force. Drag on an aircraft or any other object depends on NUMBER of factors such as local dynamic PRESSURE q, area S etc. A TYPICAL value of drag can be GIVEN as, Drag D = qSCD where, CD = drag coefficient.

Discussion

40.	If Lift produced by wing is 350N then, determine lift coefficient. Given q = 35Pa and S=8.5 m^2.(a) 1.174(b) 2.8(c) 5.6(d) 4.37I got this question in an internship interview.This intriguing question comes from Aerodynamic Coefficients in chapter Aerodynamics of Aircraft Design
Answer» The CORRECT CHOICE is (a) 1.174 The best I can EXPLAIN: Lift coefficient = lift / QS = 350/358.5 = 1.174.

Discussion

41.	Determine Flat plate skin friction coefficient if Reynolds number is 123500. Consider flow to be laminar.(a) 0.0038(b) 1.234(c) 0.045(d) 123500I got this question in an interview for job.Query is from Aerodynamics in division Aerodynamics of Aircraft Design
Answer» Right OPTION is (a) 0.0038 Easy explanation: Laminar flow flat plate SKIN friction COEFFICIENT = 1.328 / (Reynolds number^0.5) = 1.328 / (123500^0.5) = 0.0038.

Discussion

42.	Consider equivalent skin friction coefficient as 0.0025 and Swet/Sref = 0.6. Evaluate parasite drag.(a) 0.0015(b) 02.34(c) 1.23(d) 0.000025I had been asked this question at a job interview.This key question is from Aerodynamics topic in division Aerodynamics of Aircraft Design
Answer» RIGHT option is (a) 0.0015 Best explanation: PARASITE drag = EQUIVALENT SKIN friction coefficient(Swet/Sref) = 0.00250.6 = 0.0015.

Discussion

43.	A subsonic aircraft has unswept wing which has maximum lift coefficient of 1.4. Now, consider wing is provided sweep of 25° at quarter chord point. Now, determine the change in maximum lift coefficient due to the provision of sweep.(a) Maximum Lift coefficient will be reduced by 0.2580 amount(b) Increment by 1.245(c) Decreases by 0.0476 amount(d) Maximum lift coefficient will increase by 56%I had been asked this question in class test.The doubt is from Aerodynamics topic in section Aerodynamics of Aircraft Design
Answer» Right answer is (a) MAXIMUM Lift coefficient will be reduced by 0.2580 amount Easy explanation: Given, unswept maximum lift coefficient CL1 = 1.4 Now, sweep of 25° is provided at quarter chord point. Hence sweep angle at quarter chord s = 25° Maximum lift coefficient CL2 = CL10.9cos (a) = 1.40.9cos (25°) = 1.1419. Now, CHANGE in maximum lift coefficient = CL2 – CL1 = 1.1419 – 1.4 = -0.2580. Hence, by implementing the sweep of 25° maximum lift coefficient is reduced by 0.2508 UNIT.

Discussion

44.	Following diagram represents _______(a) lift curve slope vs mach number(b) drag polar(c) thrust required minimum(d) wing loading chartThe question was posed to me in an interview for internship.The doubt is from Aerodynamics in section Aerodynamics of Aircraft Design
Answer» Correct ANSWER is (a) lift curve slope vs mach number Easiest explanation: The above diagram is showing a TYPICAL variation between lift curve and Mach number. Drag polar is nothing but the drag variation with lift or angle of ATTACK. It is used to ESTIMATE drag properties of airfoil and WING. Wing loading is defined as the ratio of weight to the reference area.

Discussion

45.	Flat plate skin friction coefficient depends upon _____________(a) mach number only(b) reynolds number only(c) mach number, reynolds number etc(d) weight of the aircraftThis question was posed to me during an online interview.I'd like to ask this question from Aerodynamics in chapter Aerodynamics of Aircraft Design
Answer» Correct answer is (a) mach number only To explain I would SAY: Flat plate SKIN friction coefficient depends UPON number of factors including Mach number, Reynolds number, type of flow ETC. Mach number is used to provide information about speed of the object with respect to the speed of SOUND.

Discussion

46.	Determine the value of form factor for fuselage if fuselage fineness ratio f is 1.2.(a) 35.725(b) 12(c) 100(d) 423.2The question was asked during an interview.My question is taken from Aerodynamics topic in chapter Aerodynamics of Aircraft Design
Answer» RIGHT option is (a) 35.725 To explain I would SAY: Form factor = 1 + (60/f^3) + (f/400) = 1 + (60/1.2^3) + (1.2/400) = 1+34.722+0.003 = 35.725.

Discussion

Explore topic-wise InterviewSolutions in .

Aerodynamic forces are generated due to ______________(a) shear and pressure force acting on body(b) shear effects only(c) only pressure forces(d) twisting of beamThe question was asked in exam.My doubt stems from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design

For ideal flow, total pressure along streamline will be _________(a) constant(b) increases(c) decreases(d) always decreases by halfThis question was posed to me in class test.I would like to ask this question from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design

Increment in the skin friction drag due to prop-wash is called _________(a) scrubbing drag(b) vortex(c) swirl(d) curling flowThe question was asked during an online interview.Asked question is from Aerodynamic Forces in portion Aerodynamics of Aircraft Design

Skin friction drag is defined as _________(a) drag due to friction between skin and fluid flow(b) wing lift drag(c) such drag does not exist(d) lift inducedThe question was asked in quiz.I need to ask this question from Aerodynamic Forces in chapter Aerodynamics of Aircraft Design

Following diagram represents __________(a) plain flap(b) aileron(c) rudder(d) spoilerThe question was asked in exam.My question is taken from Aerodynamics in section Aerodynamics of Aircraft Design

_______ is one of the sources of drag.(a) Viscous separation(b) Drafting(c) Signal strength(d) Lift onlyThis question was posed to me in an online quiz.This interesting question is from Aerodynamic Forces in chapter Aerodynamics of Aircraft Design

The change in local air flow velocity will produce small change in skin friction drag.(a) True(b) FalseThe question was asked in an online interview.My question is from Aerodynamic Forces topic in division Aerodynamics of Aircraft Design

Following diagram represents ___________(a) uncambered wing lift curve(b) cambered airfoil lift curve(c) cambered wing lift curve slope(d) uncambered airfoilI got this question at a job interview.My question comes from Aerodynamics in portion Aerodynamics of Aircraft Design

Following diagram represents _______________(a) cambered wing lift curve(b) drag polar(c) thrust loading(d) power loadingI had been asked this question during an interview for a job.This interesting question is from Aerodynamics in division Aerodynamics of Aircraft Design

A supersonic 2D airfoil has Mach number of 1.5. Find Lift curve slope of the airfoil.(a) 0.062 per degree(b) 0.062 per rad(c) 24 per degree(d) 12.56 per degreeI have been asked this question in quiz.I'm obligated to ask this question of Aerodynamics in portion Aerodynamics of Aircraft Design

Following diagram represents ______________(a) cambered wing drag polar(b) cambered airfoil drag polar(c) symmetric wing drag polar(d) drag polar of an airfoilThis question was posed to me during an online exam.My doubt stems from Aerodynamic Coefficients in division Aerodynamics of Aircraft Design

Drag which is produced due to lift is called?(a) Induced drag(b) Parasite drag(c) Weight(d) Thrust dragThis question was addressed to me at a job interview.The doubt is from Aerodynamic Forces topic in chapter Aerodynamics of Aircraft Design

Equivalent skin friction coefficient can be used to provide initial estimation of the parasite drag.(a) True(b) FalseI got this question in an internship interview.This interesting question is from Aerodynamics topic in portion Aerodynamics of Aircraft Design

The location of separation point will depend on ________(a) curvature of the body(b) body weight(c) mass of body(d) only on body lengthThis question was addressed to me in examination.My question is taken from Aerodynamic Forces in portion Aerodynamics of Aircraft Design

Which of the following is a method for estimating the potato drag?(a) Equivalent skin friction method(b) Mach number(c) Weight only(d) Conceptual designThe question was posed to me in examination.The question is from Aerodynamics topic in chapter Aerodynamics of Aircraft Design

To get initial estimation of the parasite drag, aircraft wetted area can be multiplied by _____(a) equivalent skin friction coefficient(b) weight(c) lift(d) wing spanThe question was posed to me in class test.Question is taken from Aerodynamics in division Aerodynamics of Aircraft Design

A 2D airfoil is operating at 0.6M. Find the approximate value of lift curve slope in per rad.(a) 7.85(b) 1.9(c) 2.3(d) 3.87I got this question during an internship interview.This interesting question is from Aerodynamics in portion Aerodynamics of Aircraft Design

Which of the following is correct for nacelle form factor (FF)?(a) FF = 1+(0.35/f)(b) FF = 1*(0.35/f)(c) FF = 1-(0.35/f)(d) FF = 1/(0.35/f)The question was posed to me during an interview.Query is from Aerodynamics in portion Aerodynamics of Aircraft Design

If an aircraft as pitching moment of 10 Nm and dynamic pitching moment is about 8.25Nm. Find the moment coefficient Cm.(a) 1.21(b) 3(c) 5.62(d) 0.0921The question was posed to me in quiz.The origin of the question is Aerodynamic Coefficients in division Aerodynamics of Aircraft Design

Equivalent skin friction coefficient may include ______________(a) skin friction and separation drag(b) only wave drag(c) only skin friction drag(d) only thrust loadingI got this question in homework.My query is from Aerodynamics topic in division Aerodynamics of Aircraft Design

Induced drag of the airfoil is _____(a) 0.0N(b) 1.2N(c) 20 N(d) 25.8KNThis question was addressed to me in semester exam.This intriguing question originated from Aerodynamic Forces in section Aerodynamics of Aircraft Design

Wave drag is produced due to ________(a) shock wave formation(b) incompressible flow(c) fluid is not compressible(d) flow separation of incompressible flowI had been asked this question in exam.Asked question is from Aerodynamic Forces in section Aerodynamics of Aircraft Design

Which of the following is correct?(a) D = q*S*CD(b) D = q*S*CD*ρ(c) D = q*CD(d) D = qI have been asked this question in my homework.The origin of the question is Aerodynamic Coefficients in division Aerodynamics of Aircraft Design

If Lift produced by wing is 350N then, determine lift coefficient. Given q = 35Pa and S=8.5 m^2.(a) 1.174(b) 2.8(c) 5.6(d) 4.37I got this question in an internship interview.This intriguing question comes from Aerodynamic Coefficients in chapter Aerodynamics of Aircraft Design

Determine Flat plate skin friction coefficient if Reynolds number is 123500. Consider flow to be laminar.(a) 0.0038(b) 1.234(c) 0.045(d) 123500I got this question in an interview for job.Query is from Aerodynamics in division Aerodynamics of Aircraft Design

Consider equivalent skin friction coefficient as 0.0025 and Swet/Sref = 0.6. Evaluate parasite drag.(a) 0.0015(b) 02.34(c) 1.23(d) 0.000025I had been asked this question at a job interview.This key question is from Aerodynamics topic in division Aerodynamics of Aircraft Design

Following diagram represents _______(a) lift curve slope vs mach number(b) drag polar(c) thrust required minimum(d) wing loading chartThe question was posed to me in an interview for internship.The doubt is from Aerodynamics in section Aerodynamics of Aircraft Design

Determine the value of form factor for fuselage if fuselage fineness ratio f is 1.2.(a) 35.725(b) 12(c) 100(d) 423.2The question was asked during an interview.My question is taken from Aerodynamics topic in chapter Aerodynamics of Aircraft Design

Which of the following is correct?(a) D = qSCD(b) D = qSCDρ(c) D = qCD(d) D = qI have been asked this question in my homework.The origin of the question is Aerodynamic Coefficients in division Aerodynamics of Aircraft Design