Aerodynamics Set 1 (Q&A)
b
A certain airoil has a lift coefficient of 0.76 at 8 degrees AOA when the aspect ratio is 6. The angle of zero lift is -2 degrees. What is the lift coefficient if the aspect ratio is 9 with the same AOA. a. 0.611 b. 0.829 c. 0.912 d. 1.2
c
A high aspect ratio wing produces a. Less sensitive gust effects b. Decrease in stall speed c. Decrease in induced drag d. Increase in lift
d
A jet aircraft with the aspect ratio of 6 is flying at maximum range settings. What is zero lift drag coefficient if the Cl is 0.75? a. 0.03 b. 0.02 c. 0.01 d. 0.09
c
A propeller aircraft with the aspect ratio of 6 is flying at maximum endurance settings. What is zero lift drag coefficient if the Cl is 0.75? a. 0.03 b. 0.02 c. 0.01 d. 0.09
a
A propeller aircraft with the aspect ratio of 6 is flying at maximum range settings. What is zero lift drag coefficient if the Cl is 0.75? a. 0.03 b. 0.02 c. 0.01 d. 0.09
c
A propeller has the diameter of 6 ft, average chord of 6 in and solidity ratio of 0.2122. How many blades does the propeller have? a. 2 b. 3 c. 4 d. 5
b
A stealth jet is flying at an altitude of 20km at a velocity of 2500 miles/hr. what is the mach angle. a. 12.4° b. 15.3° c. 6.43° d. 18.2°
d
A venturi tube at 2000 ft altitude of has an airflow at the entrance of 90fps, if the difference in pressure as by the manometer is 1.4 psi, compute for the velocity at the throat in ft/s. a. 340.1 fps b. 121 fps c. 64 m/s d. 434 fps
a
An aeroplane with the CG location behind the center of pressure of the wing can only maintain a straight and level flight when the horizontal tail loading is: a. Upwards b. Downwards c. Zero d. Upwards or downwards depending on elevator deflection
a
An aircraft weighing 1500 lbs reach the altitude of 10000 ft from 5000 ft altitude within 5 minutes. What is the power excess? a. 45.45 HP b. 50.51 HP c. 60.1 HP d. 14.9 HP
c
An aircraft weighing 2000 lbs is turning at a radius of 150 ft at the velocity of 100 fps. What is the lift produced by the aircraft? a. 6030 lbs b. 3100 lbs c. 4600 lbs d. 5000 lbs
c
An aircraft with a wing loading of 50 psf is in a level flight at a velocity of 150 fps. What is the induced drag. Assume standard sea level conditions. AR=6 a. 0.201 b. 0.012 c. 0.185 d. 0.123
c
An airplane said to be inherently stable will a. Be difficult to stall b. Not spin c. Requires less effort to control d. Have the easier tendency to pitch up or down
d
An airplane suddenly took a dive from 10000ft to 5000ft in 2minutes. What is angle of glide? a. 0° b. 6.7° c. 5.4° d. 90°
b
Compared with flap up configuration, the maximum angle of attack for flaps down configuration is a. Larger b. Smaller c. Unchanged d. Smaller of larger depends on flap deflection
a
Consider an oblique shock wave with β = 35° and pressure ratio of p₂/p₁=3. What is the upstream mach number? a. 2.87 b. 3.21 c. 4.1 d. 2.42
a
Consider and airfoil in a flow with the freestream velocity of 150 fps. The velocity increases by 75 fps at a certain point in the flow. What is the coefficient of pressure? a. -1.25 b. -2.25 c. -1.63 d. -0.97
d
Drag due to pressure imbalance in the drag direction caused by separated flow. a. Form drag b. Profile drag c. Interference drag d. Wave drag
b
During a spin to the left, which wing(s) is/are stalled first? a. Neither b. Both c. Only Left d. Only Right
b
Gyroscopic precession of the propeller is induced by a. Pitching and rolling b. Pitching and yawing c. Increase in RPM d. Increasing RPM and rolling
a
How does a swept wing decreases the critical mach number? a. It decreases the effective mach number b. The swept angle deflects the air. c. It increases the temperature above the airfoil d. Swept angle has no effect no critical mach number
c
How is adverse yaw compensated for during entry into and roll rom a turn? a. Servo tabs b. Horn balance control c. Differential aileron deflection d. Anti-balance rudder control
b
In what flight condition must an aircraft be placed in order to spin? a. Partially stalled with one wing low b. Stalled c. In a steep diving spiral. d. Nose down
c
On a symmetrical airfoil, the pitch moment for which cl=0 is? a. Positive(pitch-up) b. Negative(pitch-down) c. Zero d. Equal to the moment coefficient for stabilized angle of attack.
a
Rotation about lateral axis is called: a. Pitching b. Slipping c. Rolling d. Yawing
d
The actual distance the airplane moves during one revolution of the propeller in flight. a. Actual pitch b. Geometric pitch c. Slip d. Effective pitch
b
The angle of incidence is set at what angle? a. Angle of attack at Clₘₐₓ b. Angle of attack at (L/D)ₘₐₓ c. Afa d. Fafa
a
The maneuverability of an aeroplane is best when the: a. C.G is on the C.G limit b. Speed is low c. Flaps are down d. C.G position is forward the C.G limit
c
The maximum endurance for an propeller driven airplane happen when the airplane is set at a. (L/D)max b. (L/D)min c. (Cl³/²/Cd)max d. (Cl¹/²/Cd)max
c
The three axes of the aircraft intersects at what? a. C.P. b. A.C. c. C.G. d. Centroid
b
To determine the compressibility effects, you have to determine the: a. IAS b. Mach number c. EAS d. TAS
b
What can happen to the aeroplane flying at a speed exceeding the Vₐ? a. It will collapse if a turn is made b. It may break the elevator if fully deflected c. It may cause permanent damage because of the too large dynamic pressure d. It may suffer permanent deformation if the elevator is fully deflected upwards
b
What causes floating during landing? a. Buoyancy b. Ground effect c. Flaring d. Lift
c
What force makes an airplane turn? a. Rudder deflection Forces b. Centrifugal force c. Horizontal component of lift d. Centripetal Force
a
What is the altitude range of the isothermal region. a. 11km to 25km b. 11km to 23km c. 32000ft to 62000ft d. 32000ft to 60000ft
a
What is the dividing line between troposphere and stratosphere. a. Tropapause b. Ionosphere c. Thermosphere d. Mesopause
c
What is the dynamic viscosity (slugs/ft-s) at 12000 ft during standard conditions. a. 3.89x10⁻⁷ b. 2.01x10⁻⁷ c. 3.49x10⁻⁷ d. 4.43x10⁻⁷
d
What is the opposite of stability? a. Unstability b. Dynamic c. Statics d. Maneuverability
b
What is the purpose of the rudder on an airplane? a. To control roll. b. Directional stability c. To control overbanking tendency. d. To reduce turbulent flow behind the airplane
a
What is the purpose of wing slats? a. Reduce stalling speed. b. Decrease drag. c. Increase speed in take off
c
What is the speed of sound at stratosphere during standard conditions? a. 295 m/s b. 340.34 m/s c. 1115 ft/s d. 1024 ft/s
a
What type of flap system increases the wing area and changes the wing camber? a. Fowler flap b. Slotted flap c. Split flap d. Plain flap
b
What wing shape of wing characteristics is the least sensitive to turbulence? a. Straight wings b. Swept wings c. Winglets d. Wing dihedral
b
When a pilot makes a turn in a horizontal flight, the stall speed: a. Increases with flap extension b. Increases with the square root of load factor c. Decreases with increasing bank angle d. Increases with the square of the load factor
c
When are outboard aileron (if present) de-activated? a. Landing gear retracted b. Landing gear extended c. Flaps retracted or speed above a certain value d. Flaps extended or speed below a certain value
a
When is the blade angle and angle of attack equal in a propeller blade? a. When the plane is idle. b. During take off. c. During cruising. d. When the engine power is off.
a
When landing behind a large jet A/C, at which point on the runway should you plan to land? a. Beyond the jet's touchdown point b. If any cross wind, land on the windward side of the runway and prior to the jet's touchdown point c. At least 1000 feet beyond the jet's touchdown point d. Different runway
b
Which of the ff. will reduce induced drag? a. Low aspect ratio b. Elliptical lift distribution c. Flying at high angle of attack d. Extending flaps
c
Which phenomenon is counteracted by aileron deflection? a. Sensitivity to spiral dive b. Aileron reversal c. Adverse yaw d. Turn coordination
b
Which wing planform produces the lowest induced drag? a. Rectangular b. Elliptical c. Tapered d. Circular