Aircraft stability objectives.docx

8/14/2019 Aircraft stability objectives.docx

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June 2013

1. Downwash at tail for elliptic lift distribution of wing decreases with

a. increase in wing span b. decrease in wing span

c. increase in wing chord d. increase in wing area

2. Sweeping the wings on an aircraft is generally done to

a. reduce the effective wingspan while increasing lift

b. increase maneuverability at subsonic speeds

c. reduce wave drag at transonic and supersonic speeds

d. reduce parasite drag by removing dirt and grime

3. Choose the correct one for the propeller driven engine:

a. low thrust, lesser efficiency b. high thrust, lesser efficiency

c. low thrust, higher efficiency d. high thrust, higher efficiency

/

4. Which combination of atmospheric conditions will reduce aircraft takeoff and climb

performance?

a. low temperature, low-relative humidity; and low-density altitude

b. high temperature, low-relative humidity, and low-density altitude

c. high temperature, high-relative humidity, and high-density altitude

d. none of the above

5. For propeller driven aircraft, the direct effects on stability are induced due to

a. propeller slip stream and normal force developed by propeller

b. thrust and normal force developed by propeller

c. propeller slip stream and thrust

d. propeller slip stream and jet induced flow

6. For a statically stable airplane, slope of elevator deflection versus lift coefficient

increases (i.e. will be less negative) as

a. lift coefficient decreases

c. static margin increases

b. static margin decreases


7. For a longitudinally stable airplane, required elevator deflection to trim the airplane at

CL= 0 is

a. positive b. negative c. zero d. none of the above

8. In an aircraft, elevator control effectiveness determinesa. turn radius b. forward-most location of the centre of gravity


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c. location of the neutral point d. aft-most location of the centre of gravity

9. In presence of small positive sideslip angle ()and small wing dihedral angle ( ), the

angle of attack of starboard wing is

a. increased by b. decreased by c. increased by / d. decreased by /

10. Spiral divergence can be avoided by

(a) increasing dihedral angle of wing and keeping directional static stability level to

minimum

(a) decreasing dihedral angle of wing and keeping directional static stability level to

minimum

(b) increasing dihedral angle of wing and keeping directional static stability level to

maximum

(c) decreasing dihedral angle of wing and keeping directional static stability level to

maximum

December 2012

1. Structural, loads due to turbulent air are imposed on the aircraft in the

a. troposphere b. stratosphere

c. ionosphere d. exosphere

2. Critical Mach number of an airfoil

a. increases with the increase in airfoil thickness

b. increases with the decrease in airfoil thickness

c. decreases with the decrease in airfoil thickness

d. remains constant with the increase/decrease in airfoil thickness

3. Maximum range for a jet aircraft occurs at:l velocity at which

a. is maximum b. is minimumc. is maximum d. is minimum

4. For level and unaccelerated flight, the velocity at minimum power required is

a. greater than the velocity at minimum thrust required

b. less than the velocity at minimum thrust required

c. equal to the velocity at minimum thrust required


5. To ensure safety during the takeoff the lift off velocity is

a. 10 % higher than stalling speed b. 15 % higher than stalling speed

c. 20 % higher than stalling speed d. 25 % higher than stalling speed

6. An airplane with a larger wing as compared to smaller wing has


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a. more longitudinal static stability

b. less longitudinal static stability

c. same longitudinal static stability

d. longitudinal static stability for an aft tail airplane if the aerodynamic center of

larger wing is behind c.g of the aircraft

7. Let an airplane in a steady level flight be trimmed at a certain speed. A level and

steady flight at a higher speed could be achieved by changing.

a. engine throttle only b. elevator only

c. throttle and elevator together d. rudder only .

8. The center of gravity position, at which stick force per g is zero, is defined as

a. stick fixed neutral point a. stick fixed neutral point

c. Stick fixed maneuvering point d. stick free maneuvering point

9. An aircraft with respect to disturbance in bank without side-slip is

a. Neutrally stable

b. Statically stable

c. Statically unstable

d. None of the above

10. For stable dihedral effect

a. rolling moment due to side-slip is positive

b. rolling moment due to side-slip is negativec. yawing moment due to side-slip is positive

d. yawing moment due to side-slip is negative

June 2012

1. Moment about aerodynamic centre of cambered aerofoil at zero lift angle of attack is

equal to

a. moment about leading edge of wing. b. moment about COP of wing.

c. moment about trailing edge of the wing d. all of above.

2. At maximum lift to drag ratio condition, which of the following condition is true

a. thrust required is minimum b. thrust required is maximum

c. power required is minimum d. power required is maximum

3. Maximum endurance of a propeller driven airplane occurs at a velocity where

a. is maximum b. is minimumc. is maximum d. iS minimum

4. Total drag of the aircraft for climbing flight is


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a. greater than level flight b. less than level flight

c. equal to level flight d. none of the above

5. The value of load factor in unaccelerated flight is

a. greater than one b. less than onec. one d. zero

6. Longitudinal static stability of the aircraft decreases with

a. increase in horizontal aft tail area b. decrease in horizontal aft tail area

c. decrease in control effectiveness d. increase in static margin

7. Trim lift coefficient of the aircraft decreases as

a. longitudinal static stability decreases

b. center of gravity of the moves in the forward direction

c. longitudinal static stability increases and center of gravity moves towards tail

d. longitudinal static stability decreases. And center of gravity moves towards

nose

8. The rolling moment due to side-slip is negative for

a. directional static stability b. directional static instability

b. lateral static stability d. lateral static instability

9. For directional static stability of the aircraft, which of the following condition is true?

a. fuselage contribution is stable\b. fuselage plus wing contribution is stable

c. fuselage plus tail contribution is unstable

d. fuselage plus tail contribution is stable

10. Contribution of wing dihedral to directional static stability increases with

a. increase in sideslip b. decrease in sideslip

c. increase in lift coefficient d. increase in profile drag coefficient

December 2011

1. The region of troposphere is characterized by

a. high steady winds

b. low steady winds

c. gusting winds and turbulence

d. free of gusts and turbulence

2. The drag divergence Mach number of an airfoil

a. is a fixed number for a given airfoil

b. is always higher than the critical Mach number


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c. is equal to the critical Mach number at zero angle of attack

d. is the Mach number at which a shock wave first appears on an airfoil

3. One of the criteria for high speed airplane is that the critical Mach number should be

as high as possible possible. Therefore, high speed subsonic airplanes are usuallydesigned with

a. laminar flow

b. diamond airfoils

c. thick airfoils

d. thin airfoils

4. For maximum range of a glider, which of the following conditions is true?

a. lift to drag ratio is maximum

b. rate of descent is minimum

c. descent angle is maximum

d. lift to weight ratio is maximum

5. In steady turning flight, the aircraft with smaller values of wing loading will have

a. turn rates and higher radius of turn

b. lower turn rates and lower radius of turn

c. higher turn rates and higher radius of turn

d. higher turn rates and lower radius of tum

6. If the center of gravity of the aircraft moves forward, the static longitudinal stability ofthe aircraft will

a. always increase

b. some time increase

c. remain same

d. always decrease

7. For a canard configuration, the stick free static longitudinal stability is

a. more than the stick fixed static longitudinal stability

b. less than the stick fixed static longitudinal stability

c. is equal to the stick fixed static longitudinal stability


8. The elevator angle per g in pull ups maneuver decreases due to

a. shift in c.g. of the aircraft towards stick fixed neutral point

b. increase in velocity only

c. both increase in velocity and shift in c.g. of the aircraft towards stick fixed

neutral point


9. The static lateral stability of the airplane increases with


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a. wing dihedral

b. wing leading edge sweep

c. high wing configuration

d. all of the above

10. Complex roots with real parts negative of a dynamic system indicates

a. pure convergent motion

b. pure divergent motion

c. damped oscillatory motion

d. undamped oscillatory motion

June 2011

1. Uprising smoke from a tall chimney on a sunny afternoon indicatesa. Stable atmosphere

b. Unstable atmospherec. Neutral atmosphered. Nothing specific

2. In the aerodynamics of airfoil and wing terminology (usual notations)a. a < ao

b. a > aoc. a = aod. a ~ ao

3. Then Cmac- CLcurve of an airfoil section is a straight linea. Parallel to the CLaxis

b. Parallel to the Cmacaxisc. Inclined at small angle to the CLaxisd. Inclined at small angle to the Cmacaxis

4. A prop driven airplane must be flown for maximum range ata.

b. c. d.

5. Aerodynamic damping of short period mode is proportional toa.

b. c.


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d. 6. In phugoid mode of oscillations of an airplane, the time period is proportional to

a. b.

Pitch up velocity

c. Forward speedd. Pitch down velocity

7. In an assisted take-off of a military airplane, the JATO unit is fireda. At t = to

b. At t = to+

c. After about half the take-off run is covered

d. After about 75% of the take-off run is covered

8. The sweep back of a wing produces additional effect ofa. Negative dihedral effect

b. Positive dihedral effectc. Rolling stabilityd. None of above

9. The airplane drag polar is based upon the area given bya. Wetted area of the airplane

b. Wetted area of the wingc. Planform area of the airplaned. Planform area of the wing

10.The deployment of spoilers at touch down of an airplanea. Increases ground reaction

b. Increases dragc. Increases drag and reduces liftd. Increases ground friction

December 2010

1. The adiabatic lapse rate for stability of atmosphere isa. 6.5 K per km

b. 7.5 K per km

c. 8.75 K per km

d. 9.75 K per km

2. While in turning flight at an angle , the load factor n on an airplane isproportional to

a. cos b. sec


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c. sin d. tan

3. Stalling velocity Vsf (flaps down) of an airplane is related to stalling velocity Vsforthe same airplane as belowa. Vsf < Vs

b. Vsf > Vsc. Vsf = Vsd. Vsf Vs

4. This parameter must be maximum for maximum range of a jet driven airplanea.

b. c. d.

5. In an airplane, a distinct advantage' of deflected flaps at touch down is to havea. the same angle of incidence as that of the take-off

b. more angle of incidence as that at the take-off

c. Lesser angle of incidence as that at the take-off

d. almost same angle of incidence as that at the take-off

6. Increase in weathercock stability of an airplane results ina. increase in roll to yaw ratio

b. decrease in roll to yaw ratioc. no change in roll toyaw ratiod. nothing definite in roll to yaw ratio

7. Airplane spin is aa. static phenomenon

b. pre-stall phenomenonc. post stall phenomenond. all of the above taken together

8. Recovery from spin is made bya. moving stick maximum forward first

b. Applying full opposite rudder first


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c. (a) & (b) taken together simultaneouslyd. aileron control in the first instance

9. Aerodynamic damping in the longitudinal dynamics of an airplane isa.

directly proportional to its pitching velocityb. indirectly proportional to its pitching velocity

c. not dependent upon its pitching velocityd. proportional to-its pitching angle

10.Frequency of oscillations in longitudinal dynamics is represented bya. itsMOI about the longitudinal axis

b. its static stabilityc. itsMOI about the lateral axisd. all of above taken together .

June 2010

1. Sun rise period indicatesa. stable atmosphere

b. unstable atmospherec. neutral atmosphered. normal atmosphere

2. The maneuver point stick free,NIII liesa. ahead of

b. aft of c. aft of d. aft of

3. Drag on an airfoil at small 'angles of attack, consist of say

a. 80% pressure drag and 20 % skin friction dragb. 50% pressure drag and 50 % skin friction .dragc.

30% pressure drag and 60 % skin friction dragd. 20% pressure drag and 70 % skin friction drag

4. Drag divergence Mach number of an airfoil depends upon

a. its thickness distribution ,b. its maximum thicknessc. its camber distributiond. its maximum camber

5. The stalling behaviour of an airfoil is a function of its

a. camber distributionb. maximum thickness


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c. leading edge radiusd. trailing edge angle

6. A leading edge strake On a swept back wing airplane

a.

is an auxiliary lifting surfaceb. is a kind of filter for smoothness of flow at the wing - body junction.c. Acts as energy provider for boundary layer on the wing.d. Acts to remove, the dead pockets of air flow on the wing.

7. For a' symmetrical airfoil section. About its a.c. is;a. definitely positive

b. definitely negativec. Definitely zero.d.Nothing definite.

8. For an airplane with stable c.g.

a. Nose down tab is required for trimb. Nose up tab is required for trim.c. No tab is requiredfor trim.d. none of above

9. A flying wing will require

a. b. c. d. Neutral longitudinal stability.

10. Ahead wind during cruise condition of an airplane results in

a. Higher TASb. Lower TASc. Higher IAS.d. Lower IAS

December 2009

I. Pick up the correct answer in each part from the given four alternatives:-

1. The reduction in take-off ground run S1, in the presence of a head wind of Vw is

given by

a. ( )

b. (

)


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c. ( )

d. ( ) 2. Rate of climb of an airplane depends upon its

a. Excess powerb. Excess thrustc. Specific excess powerd. specific excess thrust

3. The airplane efficiencies are related asa.

b.

c. d.

4. Rudder effectiveness is a function of

a. its air foil section geometryb. its airfoil section, geometry and angle of attackc. the area ratio of movable part to the total area.d. the area ratio of movable art to the fixed part.

5. Maximum endurance of a sail plane is directly proportional to its

a. aerodynamic efficiencyb. lightness of its structural weightc. drag coefficientd. wing loading

6. Stalling angle sfflaps deployed is related to stalling angle , flaps nested asa.

b.

c. d.

7. The adverse yaw in a flight can be avoided by the application of

a. opposite aileronsb. in-phase rudderc. spoilers aloned. spoilers and opposite rudder

8. A high wing airplane requires


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a. enhedral for rolling stabilityb. dihedral for: rolling stabilityc. no dihedral for rolling stability ,d. enhedral / dihedral for rolling stability as the case may be

9. A swept back, low wing gene." aviation airplane is sometimes provided

a. dihedral for rolling stability .r5lb. enhedral for rolling stability ~c. dihedral for Sufficient ground clearance of the power plantd. enhedral for Sufficient ground clearance of the power plant

10. Longitudinally stable airplanes, static margin is

a. zerob. negativec. Positived. not related

June 2009

I. Pick up the correct answer in each part from the given four alternatives1. Shorter take-off runs are required with,

a. higher wing loadingsb. moderate wing loadings and tail windsc. moderate wing loading with flaps down,d. low wing loading

2. Dorsal fin is provided to prevent

a. adverse yawb. Dutch rollc. rudder lock ",'d. dihedral effect

3. Lateral- Direction oscillations are also known as

a. Roll subsidenceb. Directional divergencec. Dutch Rolld. Dihedral effect

4. Elevator effectiveness is a function of

a. its airfoil section geometryb. its airfoil section-geometry and angle of attackc. the area ratio of movable part to the fixed partd. the area ratio of movable part to the total area


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5 .Theabsolute ceiling of an airplane is a function of its

a. Maximum lift coefficientb. minimum dragc.

engine powerd. wing loading

6. for weathercock stability of an airplane (with usual notation in directional

stability),

a.

b.

c.

d. 7. The adverse yaw in in a flight can be corrected by the application of

a. Opposite aileronsb. Opposite ruddersc. Opposite elevatorsd. All of this at a time


a. Nose down tab is required for trimb. Nose up tab is required for trimc. No tab is required for trimd. Flight in trim conditions is ruined out

9. The equilibrium condition , representsa. Short period oscillationsb. Dutch roll oscillationsc. Phugoid oscillationsd. Spiral oscillations

10. Substantial pitching accelerations are present in

a. Short period oscillationsb. Dutch roll oscillationsc. Phugoid oscillationsd. Spiral divergence


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December 2008

Pick up the correct answer in each pm from the given four alternatives:-

1.

Sun rise period indicates:a. Stable atmosphereb. Unstable atmospherec. Neutral atmosphered. Normal atmosphere

2. The maneuver points stick free, liesa. Ahead of

b. Aft of c. Aft of

d. Aft of 3. Drag on an airfoil at small 'angles of attack, consist of say

a. 80% pressure drag and 20 % skin friction dragb. 50% pressure drag and 50 % skin friction .dragc. 30% pressure drag and 60 % skin friction dragd. 20% pressure drag and 70 % skin friction drag

4. Drag divergence Mach number of an airfoil depends upon

a. its thickness distribution ,b. its maximum thicknessc. its camber distributiond. its maximum camber

5. The stalling behaviour of an airfoil is a function of its

a. camber distributionb. maximum thicknessc. leading edge radiusd.

trailing edge angle

6. A leading edge strake On a swept back wing airplane

a. is an auxiliary lifting surfaceb. is a kind of filter for smoothness of flow at the wing - body junction.c. Acts as energy provider for boundary layer on the wing.d. Acts to remove, the dead pockets of air flow on the wing.

7. For a' symmetrical airfoil section. About its a.c. is;a. definitely positive

b. definitely negative


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c. Definitely zero.d. Nothing definite.


a.

Nose down tab is required for trimb. Nose up tab is required for trim.c. No tab is requiredfor trim.d. none of above

9. A flying wing will require

a. b. c. d. Neutral longitudinal stability.

10. Ahead wind during cruise condition of an airplane results in

a. Higher TASb. Lower TASc. Higher IAS.d. Lower IAS

JUNE 2008

1. Rising smoke from a chimney on a sunny day indicates,a. Stable atmosphere

b. Unstable atmospherec. Neutral atmosphered. Normal atmosphere

2. It is advised to carry out flight tests during the period;a. Sun rise

b. Sunsetc. Mid dayd. Any time convenient

3. Drag on a circular cylinder consist of saya. 80% pressure drag and 20% skin friction drag

b. 50% pressure drag and 50% skin friction dragc. 60% pressure drag and 40% skin friction dragd. 40% pressure drag and 60% skin friction drag

4. Peaks pressure distribution over an airfoil occur because ofa. The thickness distribution

b. The maximum thicknessc. The leading edge radiusd. The maximum camber


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5. The stalling behaviour of an airfoil is function of itsa. Thickness distribution

b. Maximum thicknessc. Leading edge radiusd.

Maximum chamber6. A leading edge strake on a swept back wing airplane acts to

a. Increase its b. Increase its c. Increase both and d. Increase its

7. For a symmetrical section, about its c/4 and about its a.c. are related as;a.

b. c. d.

8. Load factor n on an airplane in climbing isa. Equal to 1

b. More than 1c. Less than 1d. Close to 1 but less than 1.2

9. A high wing will providea. More longitudinal stability

b. Lower longitudinal stabilityc. Normal longitudinal stabilityd. Neutral longitudinal stability

10.A high horizontal tail plane may result ina. Better stalling characteristics of airplane

b. No effect of down wash from wingc. Lower angels of incidenced. Poor stalling characteristics of airplane

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Aircraft stability objectives.docx