Sample Problems

  1. The Mach number _______.

    • A. is the ratio between the TAS of the aeroplane and the sea level speed of sound

    • B. is the ratio between the IAS of the aeroplane and the local speed of sound

    • C. increases as the local speed of sound decreases

    • D. increases at a given TAS, when the temperature rises

  2. Which among the following statements about symmetrical and unsymmetrical airfoils is incorrect?

    • A. A symmetric airfoil at zero angle of attack produces identical velocity increases and static pressure decreases on both the upper and lower surfaces.

    • B. An unsymmetrical airfoil is able to produce an uneven pressure distribution even at zero AOA.

    • C. The first two digits of a 4-digit airfoil will give information whether an airfoil is unsymmetrical or not.

    • D. Because of positive camber, the area in the streamtube above the wing is larger than area in the streamtube below the wing and the airflow velocity above the wing is greater than the velocity below the wing

  3. When the Mach number is slowly increased in straight and level flight the first shockwaves will occur

    • A. on the underside of the wing.

    • B. somewhere on the fin.

    • C. somewhere on the horizontal tail.

    • D. at the wing root segment, upper side.

  4. The aircraft total drag in straight and level flight is lowest when the

    • A. Induced drag is equal to zero

    • B. Induced drag is lowest

    • C. Parasite drag is equal to the induced drag

    • D. Parasite drag equals twice the induced drag

  5. The Principle of Continuity states that in a tube of increasing cross-sectional area, the speed of a subsonic and incompressible airflow will:

    • A. increase

    • B. decrease

    • C. remain the same

    • D. Have no effect

  6. In accordance with Bernoulli’s Theorem, where PT = Total

    Pressure, PS = Static pressure and q = Dynamic pressure:

    • A. PT+PS=q

    • B. PT-PS=q

    • C. PT=PS-q

    • D. PS+PT=q

  7. The following unit of measurement kg-m/s² is equivalent to _____

    • A. Joule

    • B. Watt

    • C. Newton

    • D. Pascal

  8. The speed of sound is greatly a function of?

    • Density

    • Pressure

    • Temperature

    • Velocity

  9. The percentage of nitrogen in air is approximately:

    • 0.78

    • 0.6

    • 0.88

    • 0.67

  10. What qualifies a flow to be classified as subsonic?

    • Slower than the speed of light

    • Faster than the speed of sound

    • Slower than the speed of sound

    • Faster than the speed of light

  11. Combined effects of increased area and camber, it provides the greatest increase in lift among the flaps considered and results in the least drag.

    • plain flaps

    • split flaps

    • fowler flaps

    • slotted flaps

  12. High density altitude will:

    • Decrease the power produced by an engine and increase the thrust produced by the propeller or jet

    • Increase the power produced by an engine and increase the thrust produced by the propeller or jet

    • Decrease the power produced by an engine and decrease the thrust produced by a propeller or jet

    • Increase the power produced by an engine and decrease the thrust produced by the propeller or jet

  13. Yaw is defined as the movement of the longitudinal axis about which axis?

    • Lateral

    • Longitudinal

    • Vertical

    • Horizon

  14. Geometric altitude is measured as the:

    • Physical distance between aircraft and reference (e.g. Sea Level)

    • Difference in density with International Standard Atmosphere (ISA) temperature

    • Distance between the Center of the Earth and parallel surfaces around the spherical earth.

    • Pressure differential with respect to Pressure at Sea Level

  15. Sound waves travel through the air at a definite speed.

    • Indicated airspeed

    • True airspeed

    • Speed of light

    • Speed of sound

  16. A line drawn from the leading edge to the trailing edge of an airfoil section and equidistant at all points from the upper and lower contours is called the:

    • Chord line

    • Camber

    • Mean camber line

    • Longitudinal axis

  17. When considering the principle of continuity for incompressible flow, what happens in a streamtube for a change in cross-sectional area?

    • rho1>rho2

    • rho1<rho2

    • rho1=rho2

    • (rho1+12)>rho2

  18. Aileron gives:

    • Lateral control about the lateral axis

    • Longitudinal control about the lateral axis

    • Lateral control about the longitudinal axis

    • Directional control about the normal axis

  19. For an aircraft climbing at a constant IAS the Mach number will:

    • Increase

    • Decrease

    • Remain constant

    • Initially show an increase, then a decrease

  20. It is a flow classification that is between subsonic and supersonic.

    • Hypersonic

    • Ultrasonic

    • High Speed Subsonic

    • Transonic

  21. Wing spoilers, when used asymmetrically, are associated with

    • Ailerons

    • Rudder

    • Flaps

    • elevator

  22. The total pressure is:

    • 1/2 ρav^2

    • static pressure minus the dynamic pressure

    • static pressure plus the dynamic pressure

    • can be measured in a small hole in a surface, parallel to the local stream.

  23. This is the measure of the average kinetic energy of the particles in a gas.

    • Pressure

    • Density

    • Specific Volume

    • Temperature

  24. A type of aerodynamic flow where effects of friction are held negligible.

    • Incompressible

    • Compressible

    • Inviscid

    • Viscous

  25. If a fluid is moving steadily and uniformly through a closed pipe or a stream tube, the mass flow of fluids passing one section must be the same as the mass of fluid passing any other section in one second.

    • Bernoulli's principle

    • Law of continuity

    • Newton's law

    • Pascal's law

  26. The purpose of the vertical fin is to provide:

    • directional stability

    • longitudinal stability

    • lateral stability

    • vertical stability

  27. An aircraft's rate of climb will be equal to zero if?

    • Power available is greater than the power required

    • Power available is less than the power required

    • Power required is greater than the power available

    • Power required is equal to power available

  28. When Reynold's number is above 4000 the flow is

    • Flow separation

    • Turbulent

    • Laminar

    • Transition point

  29. The maximum altitude above sea level at which a given airplane would be able to maintain horizontal flight under air conditions.

    • Service Ceiling

    • Climb Ceiling

    • Absolute Ceiling

    • None of the above

  30. What is the relationship of lift, drag, thrust, and weight when the airplane is in straight and level flight?

    • lift drag and weight equal thrust

    • lift equals weight and thrust equals drag

    • all forces are equal

    • lift and weight equal thrust and drag

  31. Which of the following will reduce induced drag?

    • Extending the flaps

    • Elliptical lift distribution

    • Low aspect ratio

    • Flying at high angles of attack

  32. A design airplane intended to be certified as a commuter category under FAR part 23 has the following specifications: design gross weight is 3,100 lb, wing span is 34 ft, MAC is 4.75 ft, and maximum lift coefficient is 1.35 with flaps retracted. What is the required minimum cruise speed?

    • 244 fps

    • 167 fps

    • 144.6 fps

    • 158 kts

  33. The power required curves for an increase in altitude show that the:

    • PR remains the same as altitude increases

    • PR increases by the same amount as the velocity

    • PR increases but the velocity does not

    • PR decreases by the same amount as the velocity

  34. An example of differential aileron deflection during initiation of left turn is:

    • Left aileron: 5° down, Right aileron: 2° up

    • Left aileron: 2° down, Right aileron: 5° up

    • Left aileron: 5° up, Right aileron: 2° down

    • Left aileron: 2° up, Right aileron: 5° down

  35. In the equation CD = Cdo + Cdi, Cdo is

    • Profile Drag Coefficient

    • Induced Drag Coefficient

    • Total Drag

    • Drag at minimum weight

  36. What happens to the value of lift as velocity is doubled?

    • lift is doubled

    • lift is tripled

    • lift is quadrupled

    • lift is reduced by half

  37. Flow in which the streamlines are smooth and no disruption

    • Flow separation

    • Turbulent

    • Laminar

    • Transition point

  38. Which of the following is not an equation for calculating the aspect ratio?

    • b/c

    • S/c^2

    • b^2/S

    • b^2/c^2

  39. Induced drag may be reduced by:

    • the use of a wing tip with a much thinner aerofoil

    • an increase in aspect ratio

    • an increase in the taper ratio of the wing

    • a decrease of the aspect ratio

  40. What is the approximate value of the lift of an aeroplane at a gross weight of 50,000 N, in a horizontal coordinated 45 degrees banked turn?

    • 50,000 N

    • 80,000 N

    • 70,000 N

    • 60,000 N

  41. Geometric Pitch is the distance moved:

    • In one revolution

    • In one revolution with slip

    • in one revolution without slip

    • angle of root chord to tip chord

  42. A wing with a very high aspect ratio (in comparison with a low aspect ratio wing) will have:

    • Increased drag at high angles of attack

    • A low stall speed

    • Poor control qualities at low airspeeds

    • Better longitudinal stability

  43. The stalling speed of aircraft will?

    • increase if it's heavier

    • decrease if it's heavier

    • is always constant

    • increase as angle of attack increases

  44. An airplane is making a turn of 1/8 mile radius at a speed of 225 mph. What is the load factor?

    • 5

    • 5.9

    • 5.5

    • 5.2

  45. How will the density and temperature change in a supersonic flow from a position in front of a shock wave to behind it?

    • Density will increase, temperature will increase

    • Density will increase, temperature will decrease

    • Density will decrease, temperature will increase

    • Density will decrease, temperature will decrease

  46. A 22,240-pound airplane has an excess power of 56 kWatts at sea level and a service ceiling of 3.66 kilometers. Calculate its rate of climb at absolute ceiling.

    • 30.49 inches per minute

    • 100 ft. per minute

    • negative 50 fpm

    • 0 fpm

  47. For an airplane flying at 400 knots at 25,000 ft altitude, find the critical value of the pressure coefficient.

    • -0.934

    • 0.915

    • -0.884

    • 0.873

  48. The bow wave will appear first at:

    • M = Mcrit

    • M = 0.6

    • M = 1.3

    • M = 1.0

  49. The Mach number:

    • is the ratio between the TAS of the airplane and the local speed of sound

    • is the ratio between the IAS of the airplane and the speed of sound at sea level

    • is the ratio between the IAS of the airplane and the local speed of sound

    • increases at a given TAS, when the temperature rises

  50. An airplane weighing 3,000 lb has a half area of 175 sq-ft. What is the horsepower required for the entire wing when flying at 90 fps (CD = 0.0561)?

    • 15.465 hp

    • 22 hp

    • 31 hp

    • 18 hp

  51. All motion or changes in aircraft attitude occurs about which position?

    • Aerodynamic center

    • Center of pressure

    • Center of gravity

    • The cockpit

  52. At an airspeed of 95 mph at sea level, what is the induced drag of a monoplane weighing 4,700 lb and having a wing span of 52 ft?

    • 115.8 lb

    • 115.9 lb

    • 112.6 lb

    • 113.5 lb

  53. At sea-level, an airplane’s rate of climb is 1,000 feet per min. Its absolute ceiling is 15,000 feet. How long will it take to climb to 7,000 feet if it will fly from sea level?

    • 8.3 mins

    • 9.5 mins

    • 23.5 mins

    • 15 mins

  54. Which formula or equation describes the relationship between force (F), acceleration (a) and mass (m)?

    • a = F.m

    • F = m / a

    • F = m.a

    • m = F.a

  55. What is the mass of the gas? P = 250 lb/in^2; V = 2000 in^3; R = 36.67 ft lbf/lb R; T = 45 F

    • 6.89 lbm

    • 2.3 lbm

    • 5.25 lbm

    • 7.98 lbm

  56. The drag polar equation of an advanced light twin airplane in clean configuration can be written as: CDT = 0.0358 + 0.0405CL^2. For best endurance, the induced drag coefficient is _________.

    • 0.0358

    • 0.1074

    • 0.0405

    • 0.0716

  57. For best maximum endurance, an airplane should have the following characteristics except

    • highest propeller efficiency

    • lowest specific consumption

    • highest fuel weight

    • flight at altitude

  58. A shock wave angled 90° from the relative flow.

    • Oblique

    • Normal

    • Expansion

    • None of the above

  59. Air passes a normal shock wave. Which of the following statements is correct?

    • The temperature increases.

    • The pressure decreases.

    • The temperature decreases.

    • The velocity increases.

  60. Which statement is correct about a normal shock wave?

    • The airflow changes from supersonic to subsonic.

    • The airflow changes direction.

    • The airflow changes from subsonic to supersonic.

    • The airflow expands when passing the airfoil.

  61. To increase the critical Mach number a conventional airfoil should

    • have a low thickness to chord ratio.

    • have a large camber.

    • be used with a high angle of attack.

    • have a large leading edge radius.

  62. If an airplane is accelerated from subsonic to supersonic speeds, the center of pressure will move:

    • forward.

    • to a position near the leading edge.

    • to a position near the trailing edge.

    • to the mid chord position.

  63. When the air is passing through an expansion wave the static temperature will

    • decrease and beyond a certain Mach number start increasing again.

    • decrease.

    • increase.

    • stay constant.

  64. When air has passed a shock wave, the velocity is:

    • decreased.

    • decreased or increased, depending on Mach Number.

    • increased.

    • unchanged.

  65. At a point in an airflow the pressure, temperature, and velocity are 1 atm, 320 K, and 1000 m/s. Calculate the total temperature at this point.

    • 820 K

    • 500 K

    • 444 R

    • 233 R

  66. An airfoil is in a freestream where p = 0.75 atm, rho = 0.942 kg/m³ and V = 325 m/s. At a point on the airfoil surface, the pressure is 0.62 atm. Assuming isentropic flow, calculate the velocity at the point.

    • 1222 m/s

    • 368 mph

    • 1208 fps

    • 1111.11 fps

  67. Consider the isentropic supersonic flow through a convergent-divergent nozzle with an exit-to-throat area ratio of 10.25. The reservoir pressure and temperature are 5 atm and 600 deg R, respectively. Calculate T at the nozzle exit.

    • 145.61 R

    • 166.67 R

    • 124.51 R

    • 212 K

  68. The flight Mach number is 2.12 and the TAS is 1400 kts. The speed of sound is:

    • 700 kts

    • 520 kts

    • 660 kts

    • 600 kts

  69. In a rocket engine, liquid hydrogen and oxygen are burned in the combustion chamber, producing a combustion gas pressure and temperature of 30 atm and 3500 K, respectively. The area of the rocket nozzle throat is 0.4 sq m. The area of the exit is designed so that the exit pressure exactly equals the ambient atmospheric pressure at a standard altitude of 20 km. Assume an isentropic flow through the rocket engine nozzle with an effective value of the ratio of specific heats k = 1.22, and a constant value of the specific gas constant R = 520 J/kg·K. Solve for the area at exit.

    • 18.888 sq m

    • 17.2 sq m

    • 15.99 sq m

    • 16.5 sq m

  70. Consider a supersonic flow with M = 2, p = 1 atm, and T = 288 K. This flow is deflected at a compression corner through 20°. Calculate Mach across the shockwave.

    • 2.3

    • 1.7

    • 4.2

    • 1.21

  71. Consider a rocket engine burning hydrogen and oxygen. The combustion chamber temperature and pressure are 4000 K and 15 atm, respectively. The exit pressure is 1.174 × 10⁻² atm. Calculate the Mach number at the exit. Assume that k = 1.22 and that R = 519.6 J/kg·K.

    • 4.89

    • 5.444

    • 3.211

    • 2.205

  72. Consider a rocket engine burning hydrogen and oxygen. The total mass flow of the propellant plus oxidizer into the combustion chamber is 287.2 kg/s. The combustion chamber temperature is 3600 K. Assume that the combustion chamber is a low-velocity reservoir for the rocket engine. If the area of the rocket nozzle throat is 0.2 m², calculate the combustion chamber (reservoir) pressure. Assume that the gas that flows through the engine has a ratio of specific heats, k = 1.2, and a Molar mass of 16 g/mol.

    • 450 kPa

    • 778 kPa

    • 3030 kPa

    • 500 kPa

  73. A supersonic flow with M1 = 1.5, P1 = 1 atm, and T1 = 288K is expanded around a sharp corner through a deflection angle of 15°. Calculate M2?

    • 1.3

    • 0.9

    • 1.44

    • 2

  74. Consider a convergent-divergent nozzle with an exit-to-throat area ratio of 3. A normal shock wave is inside the divergent portion at a location where the local area ratio is A/At = 2. Calculate the exit-to-reservoir pressure ratio.

    • 0.6667

    • 0.5846

    • 0.444

    • 1.222