42 + Interview Questions in Initial Sizing in Aircraft Design Page 1 InterviewSolution

1.	Existing engine used for sizing is called as __________(a) fixed engine(b) unfixed engine(c) differential engine(d) rubber engineI had been asked this question during an interview.Asked question is from Fixed-Engine Sizing topic in chapter Initial Sizing of Aircraft Design
Answer» The correct choice is (a) fixed engine Easiest explanation: When existing engine is USED for SIZING of the aircraft then the engine is called fixed engine. Fixed ENGINES are any existing engine which can ALMOST FIT to our requirements.

Discussion

2.	Why we use fixed engine for aircraft sizing?(a) Cost effective(b) Can be stretched(c) Can be rubberized(d) Can provide variable thrust at sizingI have been asked this question in class test.I would like to ask this question from Fixed-Engine Sizing in portion Initial Sizing of Aircraft Design
Answer» Correct option is (a) Cost effective The best I can EXPLAIN: Fixed engine is more EASILY available than a rubber engine. Any EXISTING engine can save millions of DOLLARS which was going to be spend in developing the new engine. HOWEVER, we cannot stretch it during sizing but they are more cost-effective than the rubber engine.

Discussion

3.	The distance marked by ‘Lht’ represents _____(a) tail moment arm(b) tail area(c) fuselage area(d) wing lengthThe question was posed to me in semester exam.The query is from Geometry Sizing in portion Initial Sizing of Aircraft Design
Answer» The correct answer is (a) TAIL moment arm Best explanation: Above diagram is SHOWING a TYPICAL PLAN view of a wing tail configuration. Lht represents distance between wing aerodynamic center and the tail aerodynamic center of MAC. It is known as the tail moment arm.

Discussion

4.	Which of the following is correct?(a) Rubber engine can be stretched during A/C sizing(b) Rubber engine is fixed during sizing(c) Lift is always same as engine thrust(d) Engine sizing will be same for every A/C in the worldI had been asked this question in a job interview.This question is from Rubber-Engine Sizing topic in division Initial Sizing of Aircraft Design
Answer» RIGHT answer is (a) Rubber engine can be stretched during A/C sizing The best explanation: A new engine USED during sizing is flexible in terms of size, thrust etc. Such an engine is CALLED rubber engine. They can be stretched during sizing as per REQUIREMENTS. Lift will not be same as thrust. Engine sizing will be different for different requirements of AIRCRAFT.

Discussion

5.	High speed aircraft is affected by ____________(a) aileron reversal(b) flap inversion(c) drafting(d) independent from any disturbancesThis question was posed to me in final exam.My query is from Control-Surface Sizing in portion Initial Sizing of Aircraft Design
Answer» Correct option is (a) aileron reversal For explanation: Typical high speed aircrafts are affected by ‘aileron reversal’. Aileron reversal is GENERATED as a result of much COMPLEX air loads. Air loads are strong ENOUGH that they twits wing itself. This results in WRONG way ROLLING at certain speeds.

Discussion

6.	A jet fighter is designed to operate at maximum mach of 2.0. Which of the following is approximated value for empty weight fraction if rubber engine sizing is used? Given, W0 = 20000lb, AR = 5, thrust loading T.L. = 0.6 and wing loading W.L. is 25.(a) 0.8109(b) 0.8532(c) 0.526(d) 0.3562I got this question during an online exam.The origin of the question is Rubber-Engine Sizing in division Initial Sizing of Aircraft Design
Answer» Correct option is (a) 0.8109 Best explanation: Given, jet fighter with maximum Mach number Mmax = 2.0 Gross weight W0 = 20000lb, wing loading = W.L. = 25, ASPECT ratio AR = 5, THRUST loading T.L. = 0.6. For, given parameters empty weight fraction is given by, We/W0 = [a + b(W0^c)(AR ^d)(T.L.^e)(W.L.^f)(Mmax ^g)]K Now, for jet fighter a = -0.02, b = 2.16, c = -0.1, d = 0.2, e = 0.04, f = -0.1, g = 0.08, K = 1.0 We/W0 = [-0.02 + 2.16(W0^-0.1)(AR^0.2)(T.L.^0.04)(W.L. ^-0.1)(Mmax ^0.08)]1.0 We/W0 = [-0.02 + 2.16(20000^-0.1)(5^0.2)(0.6^0.04)(25^-0.1)(2^0.08)]1.0 We/W0 = -0.02+0.8309 = 0.8109.

Discussion

7.	Based on existing engine or based on new design, aircraft sizing can be done.(a) True(b) FalseThis question was addressed to me in semester exam.This interesting question is from Fixed-Engine Sizing topic in chapter Initial Sizing of Aircraft Design
Answer» The correct choice is (a) True Explanation: Aircraft sizing is process of estimating the take-off GROSS WEIGHT of the aircraft. Aircraft can be sized either by using any existing engine or by DEVELOPING new design to MEET the required parameters.

Discussion

8.	Which of the following is correct?(a) W0 = N*T per engine / Thrust loading(b) W0 = Number of engine(c) W0 = T per engine / Thrust loading(d) W0 = 1 / Thrust loadingI had been asked this question during an interview.This question is from Fixed-Engine Sizing in portion Initial Sizing of Aircraft Design
Answer» Right answer is (a) W0 = NT per engine / Thrust loading The best explanation: For FIXED engine sizing if we ALLOW range to vary then, we can simply estimate take-off gross WEIGHT as W0 = NT per engine / Thrust loading. Here, N is the total number of engine of an AIRCRAFT.

Discussion

9.	If Cvt = 0.05 then, find the vertical tail area. Given wing span b is 2m, wing area S=10m^2 and tail moment arm Lvt=1m.(a) 1m^2(b) 1cm^2(c) 1in2(d) 1.2cm^2I got this question in quiz.This question is from Geometry Sizing in division Initial Sizing of Aircraft Design
Answer» CORRECT answer is (a) 1m^2 The explanation: GIVEN, CVT=0.05, b = 2M and wing area S=10m^2. Tail moment arm Lvt is directly given so Lvt=1m. Now, tail area Svt is given by, Svt = CvtbS/Lvt = 0.05210/1 = 1m^2.

Discussion

10.	Rapid oscillations of control surface due to application of the air loads is termed as __________(a) control surface flutter(b) control surface span(c) control surface trim(d) control surface effectivenessI have been asked this question in an interview.Enquiry is from Control-Surface Sizing topic in portion Initial Sizing of Aircraft Design
Answer» Right ANSWER is (a) control SURFACE flutter The best explanation: RAPID oscillation of control surface is CALLED control surface flutter. This rapid oscillation can tear off the surface or wing/tail itself. This will induces excessive vibration as well. Effectiveness of control surface is measure of how EFFECTIVELY we can control the aircraft.

Discussion

11.	An aircraft is climbing and accelerating to reach the cruise mach number of 0.75. If aircraft is accelerating from 0.1M then, what will be the mission segment fuel fraction for this mission?(a) 0.9821(b) 0.9258(c) 0.5289(d) 0.28958I have been asked this question during an internship interview.My enquiry is from Rubber-Engine Sizing topic in portion Initial Sizing of Aircraft Design
Answer» CORRECT choice is (a) 0.9821 Best EXPLANATION: Given, after acceleration MACH NUMBER = 0.75 For given subsonic mission segment fuel fraction, = 1.0065 – 0.0325M = 1.0065 – 0.0325*0.75 = 0.9821.

Discussion

12.	Fineness ratio of fuselage is ratio of _____________(a) fuselage length and maximum diameter(b) fuselage diameter(c) fuselage diameter and maximum length(d) length of fuselage and weightThe question was asked during a job interview.This is a very interesting question from Geometry Sizing in section Initial Sizing of Aircraft Design
Answer» The CORRECT choice is (a) fuselage length and maximum diameter Easy EXPLANATION: Fineness ratio is DEFINED as the length of the fuselage to the maximum diameter of the fuselage. If fuselage has a different cross section then, EQUIVALENT diameter is USED for fineness ratio.

Discussion

13.	An aircraft is flying with fuselage having length of 1.5m and fineness ratio of 15. At which maximum diameter fuselage should be designed?(a) 0.1m(b) 0.25m(c) 5m(d) 20.5mThe question was posed to me in a national level competition.My question comes from Geometry Sizing topic in portion Initial Sizing of Aircraft Design
Answer» RIGHT choice is (a) 0.1m To ELABORATE: Given, fuselage FINENESS RATIO F=15, length l=1.5m Now, diameter D = l/F = 1.5/15 = 0.1m.

Discussion

14.	If vertical tail has length of the 2m then, find the value of rudder length.(a) 1.8m(b) 2.8m(c) 2m(d) 2.5mThe question was posed to me in an online quiz.This interesting question is from Control-Surface Sizing topic in chapter Initial Sizing of Aircraft Design
Answer» The correct CHOICE is (a) 1.8m To EXPLAIN I would SAY: Given VERTICAL length L = 2M. For, typical aircraft rudder is extended up to 90% of the length of the vertical tail. Hence, Rudder length = 90% of tail length = 90% of 2m = 0.9*2m = 1.8m.

Discussion

15.	Determine elevator chord if tail chord is 1m.(a) 0.25m-0.5m(b) 2.5m(c) 1.8m(d) 1.5-2mI have been asked this question in my homework.I'd like to ask this question from Control-Surface Sizing in division Initial Sizing of Aircraft Design
Answer» Correct ANSWER is (a) 0.25m-0.5m To EXPLAIN: Given, tail CHORD T.C. = 1m. In typical aircraft, ELEVATOR chord is 25% to 50% of tail chord. Elevator chord = 25% of T.C. to 50% of T.C. = 25% of 1 to 50% of 1 = 0.251 to 0.51 = 0.25m-0.50m.

Discussion

16.	Process of determining the take-off gross weight and required fuel weight is called as ________(a) aircraft sizing(b) aircraft Lofting(c) aircraft drafting(d) aircraft drawingThis question was addressed to me during an interview.This intriguing question comes from Rubber-Engine Sizing in chapter Initial Sizing of Aircraft Design
Answer» Correct OPTION is (a) aircraft sizing The best I can explain: Aircraft sizing is nothing but the process of estimating and evaluating the total WEIGHT of an aircraft. The weight will be estimated based on REQUIREMENTS, SPECIFICATIONS, fuel requirements etc. lofting is mathematical MODELLING of the skin.

Discussion

17.	For a given rubber engine, determine fuel burn at combat if combat time is 2.5min.(a) 2.5CT unit(b) 2.5(c) 2.89 unit(d) 2.63 kgThe question was posed to me during an interview.I need to ask this question from Rubber-Engine Sizing in chapter Initial Sizing of Aircraft Design
Answer» Correct ANSWER is (a) 2.5CT UNIT Best explanation: GIVEN, combat time d = 2.5 min. Since SFC and thrust are not mentioned we will CONSIDER their notation as C and T respectively. Now fuel burn = SFC * Thrust Combat time = CT*2.5 unit.

Discussion

18.	A jet fighter has take-off gross weight of 10000 units. Find the appropriate length of the fuselage.(a) 34 unit(b) 34.5(c) 35 unit(d) 35.65The question was posed to me in semester exam.My enquiry is from Geometry Sizing topic in division Initial Sizing of Aircraft Design
Answer» The CORRECT choice is (a) 34 unit The best I can explain: Given, take-off gross weight is W0 = 10000 unit. Now, LENGTH is given by, L = aW0^c Now, for jet fighter aircraft a=0.93, c=0.39 Hence, length of fuselage is, L = 0.9310000^0.39 = 33.76 = 34unit.

Discussion

19.	An aircraft needs to accelerate from 0.8M to 2.0M. What should be the mission segment weight fraction if fixed engine sizing is used?(a) 0.956(b) 0.9365(c) 0.937(d) 0.98052This question was addressed to me by my college professor while I was bunking the class.This intriguing question comes from Fixed-Engine Sizing in section Initial Sizing of Aircraft Design
Answer» Correct choice is (a) 0.956 To explain: For an AIRCRAFT that accelerates from 0.1M to 0.8M, the REQUIRED FUEL fraction is 0.9805. Similarly, for 0.1M to 2.0M we required a fuel fraction of 0.937 typically. Now to find fuel fraction for aircraft from 0.8M to 2.0M is GIVEN by, Fuel fraction = (required fuel fraction for 0.1M to 2.0M)/(required fuel fraction for 0.1M to 0.8M) = 0.937 / 0.9805 = 0.956.

Discussion

20.	The rubber engine can be sized for any thrust so we can have desired thrust loading.(a) True(b) FalseThis question was posed to me by my school teacher while I was bunking the class.Question is taken from Rubber-Engine Sizing in section Initial Sizing of Aircraft Design
Answer» Right option is (a) True To elaborate: Fundamental of RUBBER engine sizing method is that we are using new design of engine. New design can be made as per our requirements. Rubber engine can be SCALED according to our requirements and then the performance PARAMETERS are evaluated. Hence, rubber engine can be sized to meet our THRUST requirements.

Discussion

21.	If supersonic aircraft has fuel fraction of 0.937 as climb and accelerating segment fuel fraction then, find the cruise mach number. Consider aircraft is accelerating from 0.1M.(a) 2.0(b) 30.5(c) 5(d) 1.4The question was posed to me in an online interview.I want to ask this question from Rubber-Engine Sizing topic in section Initial Sizing of Aircraft Design
Answer» Right option is (a) 2.0 Explanation: Given, fuel fraction =0.937 For supersonic aircraft ACCELERATING from 0.1M, fuel fraction is given by, Fuel fraction = 0.991 – 0.007M -0.01M^2. 0.937 = 0.991 – 0.007M -0.01M^2. 0.01M^2 + 0.007M -0.054 = 0. Now, DIVIDING by 0.01 then, M^2 + 0.7M -5.4 = 0. Hence, by solving above EQUATION, M = 2.0 or M = -2.7. SINCE Mach number cannot be negative, ANSWER is 2.0.

Discussion

22.	Size of fixed engine can vary during sizing.(a) True(b) FalseThe question was posed to me in an interview for internship.My query is from Fixed-Engine Sizing topic in section Initial Sizing of Aircraft Design
Answer» CORRECT option is (b) False Easiest explanation: Any existing engine has pre-defined size and diameter for their design. Fixed engine will produced finite thrust and has finite thrust LOADING. We cannot ALTER the size of the particular fixed engine.

Discussion

23.	Fixed engine sizing method is adopted for aircraft. If thrust per engine is 20000 unit and thrust loading T.L. is 0.8 then, find the take-off gross weight. Given aircraft has 2 engines.(a) 50000 unit(b) 58000 unit(c) 50822(d) 32589 unitThis question was addressed to me during an internship interview.Enquiry is from Fixed-Engine Sizing topic in division Initial Sizing of Aircraft Design
Answer» The correct choice is (a) 50000 unit To EXPLAIN I WOULD say: GIVEN, number of engines N = 2, thrust per engine T = 20000 unit and thrust loading T.L. = 0.8 Now, take-off gross WEIGHT is given by, W = NT / (T.L.) = 220000/0.8 = 50000 unit.

Discussion

24.	We can reduce aileron reversal by adopting ____________(a) inboard aileron(b) inboard fuel(c) thrust reversal(d) thrust decrementI have been asked this question during an interview.I'm obligated to ask this question of Control-Surface Sizing in chapter Initial Sizing of Aircraft Design
Answer» The correct answer is (a) inboard aileron To EXPLAIN: To reduce the degree of aileron REVERSAL we OFTEN use an inboard aileron. Inboard aileron will reduce the excessive TWISTING of wing. Thrust reversal are used to decelerate aircraft.

Discussion

25.	Find the wing reference area if wing loading is 85 lb/ft^2 and aircraft has gross weight of 10000 lb.(a) 117.64 ft^2(b) 112.65 ft^2(c) 152 ft^2(d) 125 ft^2The question was posed to me during an interview.Origin of the question is Geometry Sizing topic in division Initial Sizing of Aircraft Design
Answer» CORRECT choice is (a) 117.64 ft^2 To explain I WOULD say: Given, take-off GROSS weight is W0 = 10000 LB, wing loading W.L. = 85 lb/ft^2 W.L. = W0/area, area = W0/ W.L. = 10000/85 = 117.64 ft^2.

Discussion

26.	Following diagram represents ______(a) notched aerodynamic balance(b) fluttered balance(c) overhorn balance(d) overhung balanceThis question was posed to me in final exam.This interesting question is from Control-Surface Sizing in portion Initial Sizing of Aircraft Design
Answer» The correct ANSWER is (a) notched aerodynamic balance Explanation: Above diagram is showing a TYPICAL notched aerodynamic balance. It is also called horn aerodynamic balance. We can reduce the FORCE required for DEFLECTING the control surface. However, it is not suitable for high SPEED aircrafts.

Discussion

27.	Rolling tails can be used by high speed A/C.(a) True(b) FalseI had been asked this question in a job interview.Query is from Control-Surface Sizing in section Initial Sizing of Aircraft Design
Answer» Correct option is (a) True To explain: Rolling tail is NOTHING but the horizontal tail. This horizontal tail can be DEFLECTED nonsymmetrically. Rolling tails are USED for decrease the effect of AILERON reversal.

Discussion

28.	If a wing has span of 12m. Find the approximated length of the aileron of starboard wing.(a) 2.4m(b) 20m(c) 15m(d) 25mThis question was posed to me in homework.Origin of the question is Control-Surface Sizing in section Initial Sizing of Aircraft Design
Answer» RIGHT OPTION is (a) 2.4m Explanation: For a typical wing, ailerons are extended from 50% of span to 90% of span. Given, Span of wing b=12m. Since we need to find aileron length at one wing we will divide total wing span by 2. Hence span of starboard wing = 12/2 = 6m. Length of aileron at starboard wing (right wing) = \|difference between 50% and 90% of span\| = \|50% of 6m – 90% of 6m\| = \|0.56-0.96\| = 2.4m.

Discussion

29.	What is rubber engine?(a) Engine can be rubberized for sizing(b) Engine made from rubber(c) Engine is natured rubber(d) High strength rubber engineThis question was addressed to me in semester exam.This intriguing question comes from Rubber-Engine Sizing topic in portion Initial Sizing of Aircraft Design
Answer» CORRECT choice is (a) ENGINE can be rubberized for sizing Explanation: Rubber engine as name SUGGESTS can be rubberized for sizing. When we use new concept and new engine design, we use rubber engine for sizing. Rubber ENGINES can be stretched during sizing to meet DESIRED requirements.

Discussion

30.	A typical jet transport aircraft needs to be sized based on following parameters. Wing area S=50m^2, MAC=5m. If tail volume coefficient of horizontal tail is 1 and tail area is 10m^2 then, find the required tail moment arm.(a) 25m(b) 50m(c) 25cm(d) 65inI had been asked this question in an interview.This intriguing question originated from Geometry Sizing in section Initial Sizing of Aircraft Design
Answer» The CORRECT choice is (a) 25m To explain I would SAY: Given, WING area S=50m^2, MAC=5m.

Discussion

31.	Which of the following is correct for vertical tail (VT)?(a) Cvt = LvtSvt/(bwingSwing)(b) Cvt = Lvt/(bwingSwing)(c) Cvt = Svt/(bwingSwing)(d) Cvt = Lvt*SvtThe question was posed to me in semester exam.My query is from Geometry Sizing topic in division Initial Sizing of Aircraft Design
Answer» Right option is (a) Cvt = LvtSvt/(bwingSwing) To explain I would say: For vertical TAIL Cvt represents tail volume COEFFICIENT. It is used for sizing purpose. By ADEQUATE selection of it will provide require surface area of the tail. Cvt is given by, Cvt = LvtSvt / (bwingSwing).

Discussion

32.	We can provide sizing based on new design only.(a) True(b) FalseThe question was asked in final exam.Question is from Rubber-Engine Sizing topic in portion Initial Sizing of Aircraft Design
Answer» Correct answer is (a) True For explanation: AIRCRAFT sizing is process of weight DETERMINATION BASED on different performance parameters. Aircraft can be sized in two different way; either using new design or using existing design of ENGINE which meet all the REQUIRED parameters.

Discussion

33.	As a designer let’s consider that we want to build an aircraft weighing 28000 units at take-off. How many engine will require if our thrust loading T.L. is 0.71 and thrust per engine is 10000 unit?(a) 2(b) 3(c) 4(d) 1The question was posed to me in unit test.I want to ask this question from Fixed-Engine Sizing in portion Initial Sizing of Aircraft Design
Answer» Right choice is (a) 2 For explanation I would say: Given, thrust PER engine T = 10000 unit and thrust loading T.L. = 0.71 Now, take-off gross weight is 28000 units. Now, number engines REQUIRED is given by, N = WT.L. / T = 280000.71/10000 = 1.98. We cannot use 1.98 engines so we will take the NEAREST INTEGER. Hence, the answer will be 2.

Discussion

34.	As weight varies, rubber engine _______(a) can be scaled accordingly(b) cannot be scaled accordingly(c) remain fix(d) will change as half alwaysThis question was addressed to me in unit test.Asked question is from Rubber-Engine Sizing topic in division Initial Sizing of Aircraft Design
Answer» Correct choice is (a) can be SCALED ACCORDINGLY To explain I would say: Rubber engine can be rubberized as per our requirement. If during the initial SIZING process, we need to alter the weight then, we can SCALE the rubber engine accordingly. This is ONE of the advantages of the rubber engine.

Discussion

35.	If length of typical fuselage is 20m then, find the approximate range for control canard moment arm.(a) 6m-10m(b) 2-5cm(c) 5-9in(d) 11-20mThe question was asked during an online exam.My question is based upon Geometry Sizing topic in section Initial Sizing of Aircraft Design
Answer» RIGHT OPTION is (a) 6m-10m The best I can explain: Given a typical fuselage with length L = 20m. Typical RANGE for canard (CONTROL) moment arm = 30% to 50% of the length = 30% of L to 50% of L = 30% of 20 to 50% of 20 = 0.320 to 0.520 = 6m – 10m.

Discussion

36.	Jet transport aircraft has 12m length of the fuselage. What will be the approximated value for take-off gross weight?(a) 820.68kg(b) 850kg(c) 520kg(d) 1025gI had been asked this question in an online quiz.This key question is from Geometry Sizing topic in portion Initial Sizing of Aircraft Design
Answer» Right answer is (a) 820.68kg Best EXPLANATION: GIVEN, length L=12m Now, length is given by, L = aW0^c Now, for jet TRANSPORT aircraft a=0.67, c=0.43 Hence, take-off gross weight is W0^c = L/a W0^0.43 = 12/0.67 = 17.91. Now by taking log at both side, 0.43LN W0 = ln17.91 = 2.885 lnW0 = 6.710 Hence, by USING antilog, W0 = e^6.710 = 820.68kg.

Discussion

37.	Which of the following is disadvantage of fixed engine sizing?(a) Often requires compromise in mission range or performance(b) Less costly compared to rubber engine(c) Availability is more than rubber engine(d) Has no disadvantageI have been asked this question in an interview for internship.My doubt stems from Fixed-Engine Sizing topic in portion Initial Sizing of Aircraft Design
Answer» RIGHT choice is (a) Often requires COMPROMISE in mission range or performance For explanation: In general, for any reason if our weight needs to be alter during SIZING then we NEED to PROVIDE optimization for such changes. In most of cases we need to alter the range or any other mission parameters.

Discussion

38.	Following diagram represents _____(a) overhung aerodynamic balance(b) overhorn balance(c) horn balance(d) notched balanceThe question was posed to me during a job interview.Enquiry is from Control-Surface Sizing topic in section Initial Sizing of Aircraft Design
Answer» Right choice is (a) overhung aerodynamic balance The BEST explanation: Overhung aerodynamic balance is REPRESENTED in the above diagram. It is used to reduce the amount of force require to DEFLECT a CONTROL surface. It is ALSO used to reduce the flutter effect.

Discussion

39.	For mission with payload drop, the take-off gross weight W0 is given by ____(a) W0 = Wcrew + Wdropped payload + Wfixed payload + Wfuel + Wempty(b) W0 = Wcrew + Wdropped payload + Wfixed payload + Wfuel(c) W0 = Wcrew + Wdropped payload + Wfixed payload + Wempty(d) W0 = Wcrew + Wdropped payload + Wfuel + WemptyThis question was posed to me during an interview for a job.Question is from Rubber-Engine Sizing topic in division Initial Sizing of Aircraft Design
Answer» The CORRECT choice is (a) W0 = Wcrew + Wdropped payload + Wfixed payload + Wfuel + Wempty To elaborate: TAKEOFF gross weight of the AIRCRAFT is the net or total weight of each and every possible components and systems. Typically, aircraft gross weight is DIVIDED into number of sub weight categories such as crew weight, fuel weight, empty weight etc. A typical takeoff gross weight can be expressed as W0 = Wcrew + Wdropped payload + Wfixed payload + Wfuel + Wempty.

Discussion

40.	The thrust developed by fixed engine will be ___________(a) fixed during sizing(b) unfixed during sizing(c) independent of engine(d) zero at sizingThis question was addressed to me in unit test.My question is based upon Fixed-Engine Sizing topic in division Initial Sizing of Aircraft Design
Answer» Correct OPTION is (a) fixed during SIZING The EXPLANATION: Thrust will be fixed during sizing if fixed engine is USED. Fixed engine is any existing engine that is available for use. However, when we use fixed engine we are bounded with some CONSTRAINTS such as fixed thrust. Hence, we cannot vary thrust as a rubber engine.

Discussion

41.	The purpose of fuselage is ___________(a) to provide space for cargo and passenger(b) to provide thrust(c) to provide high lift(d) to increase maximum liftI have been asked this question in an interview.Asked question is from Geometry Sizing topic in portion Initial Sizing of Aircraft Design
Answer» CORRECT option is (a) to provide space for cargo and PASSENGER Easiest explanation: Main body of the aircraft is called fuselage. Fuselage is USED to provide space for cargo, crew and passenger. Thrust is primarily provided by ENGINES. High lift is generated through high lift devices.

Discussion

42.	A general aviation single engine aircraft has gross weight of 2800lb. The aircraft has maximum speed of 130mph. Determine the approximated value of empty weight fraction if, aspect ratio AR is 9, wing loading is 15 and power loading is 12.(a) 0.5476(b) 0.6457(c) 0.8962(d) 0.9028I had been asked this question in final exam.The origin of the question is Rubber-Engine Sizing in section Initial Sizing of Aircraft Design
Answer» Correct option is (a) 0.5476 Explanation: Given, a general aviation AIRCRAFT with single engine. Maximum velocity Vmax =130mph Gross weight W0 = 2800lb, wing LOADING = W.L. = 15, Aspect ratio AR = 9, Power loading P.L. = 12. For, given parameters empty weight fraction is given by, We/W0 = a + b(W0^c)(AR ^d)(P.L.^-e)(W.L.^F)(Vmax^g) Now, for general aviation with single engine, a=-0.25, b = 1.14, c = -0.2, d = 0.08, e = 0.05, f = -0.05, g = 0.27. Hence, empty weight fraction is given by, We/W0 = -0.025 + 1.14(W0^-0.2)(AR ^0.08)(P.L.^-0.05)(W.L.^-0.05)(Vmax^0.27) We/W0 = -0.025 + 1.14(2800^-0.2)(9 0.08)(12^-0.05)(15^-0.05)*(130^0.27) We/W0 = -0.025 +.07976 = 0.5476.

Discussion

Explore topic-wise InterviewSolutions in .

Existing engine used for sizing is called as __________(a) fixed engine(b) unfixed engine(c) differential engine(d) rubber engineI had been asked this question during an interview.Asked question is from Fixed-Engine Sizing topic in chapter Initial Sizing of Aircraft Design

Why we use fixed engine for aircraft sizing?(a) Cost effective(b) Can be stretched(c) Can be rubberized(d) Can provide variable thrust at sizingI have been asked this question in class test.I would like to ask this question from Fixed-Engine Sizing in portion Initial Sizing of Aircraft Design

The distance marked by ‘Lht’ represents _____(a) tail moment arm(b) tail area(c) fuselage area(d) wing lengthThe question was posed to me in semester exam.The query is from Geometry Sizing in portion Initial Sizing of Aircraft Design

High speed aircraft is affected by ____________(a) aileron reversal(b) flap inversion(c) drafting(d) independent from any disturbancesThis question was posed to me in final exam.My query is from Control-Surface Sizing in portion Initial Sizing of Aircraft Design

Based on existing engine or based on new design, aircraft sizing can be done.(a) True(b) FalseThis question was addressed to me in semester exam.This interesting question is from Fixed-Engine Sizing topic in chapter Initial Sizing of Aircraft Design

If Cvt = 0.05 then, find the vertical tail area. Given wing span b is 2m, wing area S=10m^2 and tail moment arm Lvt=1m.(a) 1m^2(b) 1cm^2(c) 1in2(d) 1.2cm^2I got this question in quiz.This question is from Geometry Sizing in division Initial Sizing of Aircraft Design

If vertical tail has length of the 2m then, find the value of rudder length.(a) 1.8m(b) 2.8m(c) 2m(d) 2.5mThe question was posed to me in an online quiz.This interesting question is from Control-Surface Sizing topic in chapter Initial Sizing of Aircraft Design

Determine elevator chord if tail chord is 1m.(a) 0.25m-0.5m(b) 2.5m(c) 1.8m(d) 1.5-2mI have been asked this question in my homework.I'd like to ask this question from Control-Surface Sizing in division Initial Sizing of Aircraft Design

For a given rubber engine, determine fuel burn at combat if combat time is 2.5min.(a) 2.5*C*T unit(b) 2.5(c) 2.89 unit(d) 2.63 kgThe question was posed to me during an interview.I need to ask this question from Rubber-Engine Sizing in chapter Initial Sizing of Aircraft Design

A jet fighter has take-off gross weight of 10000 units. Find the appropriate length of the fuselage.(a) 34 unit(b) 34.5(c) 35 unit(d) 35.65The question was posed to me in semester exam.My enquiry is from Geometry Sizing topic in division Initial Sizing of Aircraft Design

The rubber engine can be sized for any thrust so we can have desired thrust loading.(a) True(b) FalseThis question was posed to me by my school teacher while I was bunking the class.Question is taken from Rubber-Engine Sizing in section Initial Sizing of Aircraft Design

Size of fixed engine can vary during sizing.(a) True(b) FalseThe question was posed to me in an interview for internship.My query is from Fixed-Engine Sizing topic in section Initial Sizing of Aircraft Design

We can reduce aileron reversal by adopting ____________(a) inboard aileron(b) inboard fuel(c) thrust reversal(d) thrust decrementI have been asked this question during an interview.I'm obligated to ask this question of Control-Surface Sizing in chapter Initial Sizing of Aircraft Design

Find the wing reference area if wing loading is 85 lb/ft^2 and aircraft has gross weight of 10000 lb.(a) 117.64 ft^2(b) 112.65 ft^2(c) 152 ft^2(d) 125 ft^2The question was posed to me during an interview.Origin of the question is Geometry Sizing topic in division Initial Sizing of Aircraft Design

Following diagram represents ______(a) notched aerodynamic balance(b) fluttered balance(c) overhorn balance(d) overhung balanceThis question was posed to me in final exam.This interesting question is from Control-Surface Sizing in portion Initial Sizing of Aircraft Design

Rolling tails can be used by high speed A/C.(a) True(b) FalseI had been asked this question in a job interview.Query is from Control-Surface Sizing in section Initial Sizing of Aircraft Design

If a wing has span of 12m. Find the approximated length of the aileron of starboard wing.(a) 2.4m(b) 20m(c) 15m(d) 25mThis question was posed to me in homework.Origin of the question is Control-Surface Sizing in section Initial Sizing of Aircraft Design

Which of the following is correct for vertical tail (VT)?(a) Cvt = Lvt*Svt/(bwing*Swing)(b) Cvt = Lvt/(bwing*Swing)(c) Cvt = Svt/(bwing*Swing)(d) Cvt = Lvt*SvtThe question was posed to me in semester exam.My query is from Geometry Sizing topic in division Initial Sizing of Aircraft Design

We can provide sizing based on new design only.(a) True(b) FalseThe question was asked in final exam.Question is from Rubber-Engine Sizing topic in portion Initial Sizing of Aircraft Design

As weight varies, rubber engine _______(a) can be scaled accordingly(b) cannot be scaled accordingly(c) remain fix(d) will change as half alwaysThis question was addressed to me in unit test.Asked question is from Rubber-Engine Sizing topic in division Initial Sizing of Aircraft Design

If length of typical fuselage is 20m then, find the approximate range for control canard moment arm.(a) 6m-10m(b) 2-5cm(c) 5-9in(d) 11-20mThe question was asked during an online exam.My question is based upon Geometry Sizing topic in section Initial Sizing of Aircraft Design

Jet transport aircraft has 12m length of the fuselage. What will be the approximated value for take-off gross weight?(a) 820.68kg(b) 850kg(c) 520kg(d) 1025gI had been asked this question in an online quiz.This key question is from Geometry Sizing topic in portion Initial Sizing of Aircraft Design

Following diagram represents _____(a) overhung aerodynamic balance(b) overhorn balance(c) horn balance(d) notched balanceThe question was posed to me during a job interview.Enquiry is from Control-Surface Sizing topic in section Initial Sizing of Aircraft Design

The thrust developed by fixed engine will be ___________(a) fixed during sizing(b) unfixed during sizing(c) independent of engine(d) zero at sizingThis question was addressed to me in unit test.My question is based upon Fixed-Engine Sizing topic in division Initial Sizing of Aircraft Design

The purpose of fuselage is ___________(a) to provide space for cargo and passenger(b) to provide thrust(c) to provide high lift(d) to increase maximum liftI have been asked this question in an interview.Asked question is from Geometry Sizing topic in portion Initial Sizing of Aircraft Design

For a given rubber engine, determine fuel burn at combat if combat time is 2.5min.(a) 2.5CT unit(b) 2.5(c) 2.89 unit(d) 2.63 kgThe question was posed to me during an interview.I need to ask this question from Rubber-Engine Sizing in chapter Initial Sizing of Aircraft Design

Which of the following is correct for vertical tail (VT)?(a) Cvt = LvtSvt/(bwingSwing)(b) Cvt = Lvt/(bwingSwing)(c) Cvt = Svt/(bwingSwing)(d) Cvt = Lvt*SvtThe question was posed to me in semester exam.My query is from Geometry Sizing topic in division Initial Sizing of Aircraft Design