# Aerodynamics Board Examination

Here are Aerodynamics Fundamental board examination questions reviewer:

1. Shock stall is

a. A. separation of the flow at high angles of attack and at high
Mach Numbers.
b. B. separation of the flow at the trailing edge of the wing at
high Mach Numbers.
c. C. separation of the boundary layer behind the shock wave.
d. D. separation of the flow behind the bow wave.

Question 2
Just above the critical Mach number the first evidence of a shock
wave will appear at the
a.
A. upper side of the wing.
b. B. lower side of the wing.
c. C. leading edge of the wing.
d. D. trailing edge of the wing.

Question 3
NACA 4412 was used in the construction of the airfoil. Determine
the chord (in) if the camber equals 9.12 cm.
a. A. 22.80
b. B. 29.92
c. C. 89.76
d. D. 228.00

Question 4
Consider an oblique shock wave with β = 35 deg and pressure ratio
of P2/P1=3. What is the upstream mach number?
a. A. 2.87
b. B. 3.21
c. C. 4.10
d. D. 2.42

Question 5
An aircraft model is placed in a certain wind tunnel airstream. The
density of the airstream decreases to half of the original value.

The aerodynamic drag will decrease with a factor
a. A. 8.0
b. B. 1.4
c. C. 2.0
d. D. 4.0

Question 6
A plain flap will increase CLmax by
a. A. Increasing the camber of the airfoil
b. B. Increasing angle of attack
c. C. Boundary layer control
d. D. Center of lift movement

Question 7
An elliptical planform wing has a span of 12 m and a chord of 2 m.
What is the induced drag coefficient when the lift coefficient is
0.8?
a. A. 0.034
b. B. 0.430
c. C. 0.068
d. D. 0.860

Question 8
What is μ (slugs/ft-s) at the an altitude where the speed of sound
equals 692.662 mph?
a. A. 3.04 x 10^-7
b. B. 3.24 x 10^-7
c. C. 3.64 x 10^-7
d. D. 3.84 x 10^-7

Question 9
The lift coefficient of an aircraft in steady horizontal flight is
0.4. Increase of angle of attack of 1 degree will increase the CL
by 0.09. A vertical up gust instantly changes the angle of attack
by 5 degrees. The load factor will be
a. A. 2.13
b. B. 1.09
c. C. 2.00
d. D. 3.19

Question 10
To be able to predict compressibility effects, you have to
determine the
a. A. Mach Number
b. B. EAS
c. C. TAS

d. D. IAS

Question 11
An aircraft has a stall speed of 100kt at a load factor n=1. In a
turn with a load factor of n=2, the stall speed is
a. A. 70 kt
b. B. 200 kt
c. C. 282 kt
d. D. 141 kt

Question 12
A 5000 lb airplane with wing area of 250 sq ft and power available
of 450 hp is at flight sea level standard condition. The airplane
drag to lift relation is close to CD = 0.025 + 0.048 CL^2. At
flight speed of 180 mph, the airplane drag coefficient is .
a. A. 0.0237
b. B. 0.0195
c. C. 0.0206
d. D. 0.0278

Question 13
To increase the critical Mach number a conventional aerofoil should
_
.
a. A. have a low thickness to chord ratio
b. B. have a large camber
c. C. be used with a high angle of attack

Question 14
What is the relationship of the length of a curved path, r, with
tangential velocity, v, when the strength of circulation is
constant as we move outwards from the core?
a. A. Directly Proportional
b. B. Inversely Proportional
c. C. Constant
d. D. Not related

Question 15
An aeroplane has a stall speed of 78 KCAS at its gross weight of
6,850 lbs. What is the stall speed when the weight is 5,000 lbs?
a. A. 57 KCAS
b. B. 67 KCAS
c. C. 91 KCAS
d. D. 78 KCAS

Question 16

Given the ratio of dynamic pressure and static pressure to be
0.135, calculate the Mach number. Assume air is the medium.
a. A. 0.339
b. B. 0.439
c. C. 0.539
d. D. 0.639

Question 17
An aircraft has a mass of 7200 kg and a wing span of 12 m. If the
wing loading is 1.968 kN/m^2, what is the induced drag when flying
at speeds of 200 knots at sea-level?
a. A. 1500 N
b. B. 1600 N
c. C. 1700 N
d. D. 1800 N

Question 18
Regarding curved deflecting angles, what happens to the vertical
component of force as the angle of deflection increases? Assuming
that all the other parameters remain constant.
a. A. Increases
b. B. Decreases
c. C. No relationship
d. D. Remains the same

Question 19
An aircraft is cruising at FL110. What is the ambient temperature
(K)?
a. A. 266.37
b. B. 390.06
c. C. 479.46
d. D. 557.92

Question 20
The location of the center of pressure of a positive cambered wing
at increasing angle of attack will
a. A. Shift aft
b. B. Shift in spanwise direction
c. C. Shift forward
d. D. Not shift

Question 21
In a two-dimensional flow pattern, where the streamlines converge
the static pressure will _.
a. A. not change
b. B. increase initially, then decrease
c. C. decrease

Question 22
Two identical aeroplanes A and B are flying horizontal steady
turns. Further data are:
Condition A
W= 1500 kg
Bank= 20 deg
TAS= 130 kt
Condition B
W= 1500 kg
Bank= 20 deg
TAS= 200 kt
Which of the following statements is correct?
a. A. The load factor for A is larger than the load factor for B.
b. B. The turn radius A is larger than the turn radius B.
c. C. The lift coefficient A is smaller than the lift coefficient
B.
d. D. The rate of turn A is larger than the rate of Turn B.

Question 23
It is the point in a fluid stream where the diameter of the stream
is the least and fluid velocity is at its maximum.
a. A. Converging-Diverging
b. B. Stagnation
c. C. Vena Contracta
d. D. Walls

Question 24
What is the type of flow if the computed Reynolds number exceeds
4,000?
a. A. Laminar
b. B. Transient
c. C. Turbulent
d. D. Uniform

Question 25
What force is required to push a flat plate, 3 in by 2 in at a
speed of 35 fps in a direction perpendicular to its surface?
a. A. 22.36 lbs
b. B. 11.18 lbs
c. C. 1.55 lbs
d. D. 0.078 lbs

Question 26
On five-digit NACA airfoil, the third digit corresponds to the
camber. What does it mean if the third digit is 1.
a. A. Critical
b. B. Reflex
c. C. Simple
d. D. Turbulent

Question 27
In supersonic flight aerofoil pressure distribution is
a. A. rectangular.
b. B. irregular.
c. C. triangular.
d. D. the same as in subsonic flight.

Question 28
A body is placed in a certain airstream. The airstream velocity
increases by a factor 4. The aerodynamic drag will increase with a
factor __.
a. A. 12
b. B. 16
c. C. 4
d. D. 8

Question 29
Where on the surface of a typical aerofoil will flow separation
normally start at high angles of attack?
a. A. upper side leading edge
b. B. lower side trailing edge
c. C. lower side leading edge
d. D. upper side trailing edge

Question 30
Which among the statements about Density Altitude is incorrect?
a. A. A high density altitude will decrease the power produced by
an engine because less oxygen is available for combustion
b. B. A high density altitude requires a higher true airspeed for
takeoff and landing and will therefore increase takeoff and
landing distances
c. C. Density altitude is found by correcting pressure altitude
for temperature and humidity deviations from the standard
atmosphere
d. D. None, all statements above are correct

Question 31
This gas law states that pressure and volume are inversely related
when the temperature is constant.

b. B. Boltzmann’s
c. C. Boyle’s
d. D. Charles

Question 32
The flight Mach number is 0.8 and the TAS is 400 kts. What is the
speed of sound?
a. A. 500 kts
b. B. 320 kts
c. C. 480 kts
d. D. 600 kts

Question 33
The true airspeed (TAS) is _.
a. A. higher than the speed of the undisturbed airstream about
the aeroplane.
b. B. equal to the IAS, multiplied by the air density at sea
level
c. C. lower than the speed of the undisturbed airstream about the
aeroplane
d. D. lower than the indicated airspeed (IAS) at ISA conditions
and altitudes below sea level

Question 34
When the air has passed through a normal shock wave the Mach number
is
a. A. lower than before but still greater than 1.
b. B. equal to 1.
c. C. higher than before.
d. D. less than 1.

Question 35
By what percent does the lift increase in a steady level turn at 45
degrees angle of bank, compared to straight and level flight?
a. A. 41%
b. B. 19%
c. C. 31%
d. D. 52%

Question 36
VA is
a. A. The maximum speed at which rolls are allowed.
b. B. The speed that should not be exceeded in the climb.
c. C. The maximum speed at which maximum elevator deflection up
is allowed.

d. D. The speed at which a heavy transport aircraft should fly in
turbulence.

Question 37
Which among the following statements about symmetrical and
unsymmetrical airfoils is incorrect?
a. 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. B. An unsymmetrical airfoil is able to produce an uneven
pressure distribution even at zero AOA.
c. C. The first two digits of a 4-digit airfoil will give
information whether an airfoil is unsymmetrical or not.
d. 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.

Question 38
Given g = 10m/s^2, an aircraft is in a steady turn, at a constant
TAS of 300kt, and a bank angle of 45 degrees. Its turning radius is
a. A. 2381 m
b. B. 3254 m
c. C. 4876 m
d. D. None of the above

Question 39
What is the induced drag at 100 knots of a monoplane of mass 2400
kg having a wing span of 16 m?
a. A. 632.8 N
b. B. 425.9 N
c. C. 632.6 lbf
d. D. 425.9 lbf

Question 40
How will the density and temperature change in a supersonic flow
from a position in front of a shock wave to behind it?
a. A. Density will decrease, temperature will increase.
b. B. Density will decrease, temperature will decrease.
c. C. Density will increase, temperature will increase.
d. D. Density will increase, temperature will decrease.

Question 41
Consider a rocket burning hydrogen and oxygen; the combustion
chamber pressure and temperature are 25 atm and 3,517 Kelvin,
respectively. The area of the rocket nozzle throat is 0.1 square
meters. The area of the exit is designed so that the exit pressure
exactly equals ambient pressure at a standard altitude of 30 km.

For the gas mixture assume that k = 1.22 and the molecular weight M
= 16. At a standard altitude of 30 km, calculate exit Mach number.
a. A. 5.21
b. B. 1.00
c. C. 4.35
d. D. 3.56

Question 42
A stealth jet is flying at an altitude of 20km at a velocity of
2500 miles/hr. what is the mach angle.
a. A. 12.40 deg
b. B. 15.30 deg
c. C. 6.43 deg
d. D. 18.20 deg

Question 43
The span-wise flow is caused by the difference between the air
pressure on top and beneath the wing and its direction of movement
goes from . a. A. beneath to the top of the wing via the trailing edge

b. B. the top to beneath the wing via the leading edge c.

C. beneath to the top of the wing via the wing tip

d. D. the top to beneath the wing via the wing’s trailing edge

Question 44

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

a. A. on the underside of the wing.

b. B. somewhere on the fin.

c. C. somewhere on the hoizontal tail.

d. D. at the wing root segment, upperside.

Question 45

What is the CLmax of an aircraft with a wing loading of 700 Newtons per square meter and stalling velocity of 115 miles per hour? Assumes standard sea level conditions.

a. A. 0.216

b. B. 0.233

c. C. 0.433

d. D. 0.465

Question 46

A body is placed in a certain airstream. The density of the airstream decreases to half of the original value. The aerodynamic drag will decrease with a factor .
a. A. 8.0
b. B. 1.4

c. 2

Question 47
If a symmetrical aerofoil is accelerated from subsonic to
supersonic speed the centre of lift will move .

a. A. aft to the trailing edge

b. B. forward to the leading edge

c. C. forward to the mid chord

d. D. aft to the mid chord

Question 48

The Mach number .
a. A. is the ratio between the TAS of the aeroplane and the sea
level speed of sound
b. B. is the ratio between the IAS of the aeroplane and the local
speed of sound
c. C. increases as the local speed of sound decreases
d. D. increases at a given TAS, when the temperature rises

Question 49
How does the exterior view of an aircraft change, when the trim is
used during a speed decrease?
a. A. Elevator deflected downwards by means of a trimmable
horizontal stabilizer
b. B. Nothing changes in exterior view
c. C. The elevator is deflected further downwards by means of an
upwards deflected trimtab
d. D. The elevator is deflected upwards by means of a downwards
deflected trimtab

Question 50
The aircraft total drag in straight and level flight is lowest when
the
a. A. Induced drag is equal to zero
b. B. Induced drag is lowest
c. C. Parasite drag is equal to the induced drag
d. D. Parasite drag equals 2x Cdi