Shared Flashcard Set

Details

Aerodynamics and performance
Final review
118
Other
Undergraduate 3
12/11/2007

Additional Other Flashcards

 


 

Cards

Term

Airplanes were developed primarily by:

Definition

the trial and error method

Term

The density of water changes with depth

t or F

Definition

False

Term

Out of the following, who did not experiment in flight

Definition

Bernoulli

Term

The first successful flight of an aircraft

was accomplished with a balloon

T or F

Definition

True

Term

Aerodynamics is the study of

Definition

Air in motion

Term

A balloon that is filled with air that is lighter than the surrounding air rises to a point where the internal air density is equal to the external air density is based on what principle?

Definition

Buoyancy

Term
Air density at sea level is ________ dense than air at 10,000 feet altitude.
Definition
More
Term

The density of air changes depending on

altitude because air is compressible

T or F

Definition

True

Term

What part of the atmosphere does all weather occur and also most flight operations?

Definition

Troposphere

Term
Balloons that are navigable are called
Definition
Airships
Term
Sir George Cayley, Otto Lilenthal, and Octave Chanute all had what in common?
Definition
They all experimented with gliders in the 1800s.
Term
Lighter than air aircraft are reliant on what for lateral (as opposed to vertical) movement.
Definition
Movement of an air mass and
Velocity and direction of the wind
Term
Man's first attempt at heavier than air flight was to create birdlike vehicles with wings that flapped.
Definition
True
Term
Birds are successful fliers because they can achieve lift and thrust with their feathered wings. Airplanes require;
Definition
An engine to develop forward thrust
Controls to maneuver in pitch, roll, and yaw
Stability in their design
Knowledgeable pilots
Term
Gliders and airplanes are
Definition
Heavier than air machines
Term
Who was/were the first to achieve sustained, controlled and powered flight?
Definition
The Wright Brothers
Term
A chunk of fluid that is suspended in a container of fluid will ________ due to the weight and pressure above the chunk balancing out the higher pressure below the chunk.
Definition
remain still
Term
A small contained bubble of fluid that is lighter than the surrounding fluid ________ due to the higher pressure on the bottom of the bubble.
Definition
Rises to the surface
Term
A piece of lead placed in a container of water will ________ due to the weight of the lead being _______ than the fluid that is displaced.
Definition
Sink to the bottom, heavier
Term
How are balloons made to be lighter than air?
Definition
Filled with lighter than air gas (helium)
Filled with heated air which is less dense than cooler air
Both
Term
Pressure = ……………
Definition
Force/ Area
Term
The symbol for air density is?
Definition
ρ
Term
The approximate temperature at the Tropopause is
Definition
-56˚C
Term
Air pressure at sea level is ________ than air at 30,000 feet altitude.
Definition
more
Term
The temperature of air decreases on average by how much per 1000ft
Definition
2˚C
Term
The chordline of an aerofoil is:
Definition
A straight line from the leading edge to trailing edge.
Term
A cambered aerofoil set at 0˚ angle of attack in an air stream will produce:
Definition
Lift and drag.
Term
The angle between the chord line of the aerofoil and the relative airflow is called:
Definition
The Angle of Attack.
Term
Dynamic pressure is equal to:
Definition
½ ρv²
Term
The centre of pressure of an aerofoil is:
Definition
The point on the chordline where the lift force acts.
Term
The properties of air on the top of a cambered wing producing lift:
Definition
Velocity increases, Static Pressure decreases.
Term
"Aspect Ratio" is:
Definition
Span / chord
Term
The density of a gas may be expressed as:
Definition
Mass/Volume.
Term
Which of the below actions will result in a stall every time?
Definition
Exceeding the critical angle of attack.
Term
An airfoil stalls when:
Definition
The airflow over the top surface of the wing breaks away or separates which results in a large increase in drag and a large loss of lift.
Term
If an aircraft’s wings are slightly angled upwards from horizontal as you look at it from the front forming a shallow V, this is called:
Definition
Dihedral
Term
A high aspect ratio wing will be:
Definition
Of long span and short chord, like a gliders.
Term
The wing span is the distance:
Definition
From wing tip to wing tip.
Term
A wing is tapered if:
Definition
The tip chord is less than the root chord.
Term
The stalling angle of an aerofoil of a training aircraft is approximately:
Definition
16 degrees.
Term
An aircraft's wing has a mean chord of 6m and a span of 30m. The aspect ratio is:
Definition
(a) 5.
Term
To maintain level flight at a steady airspeed:
Definition
(a) Thrust must be exactly equal to drag.
Term
The stall warning vane on an aircraft wing is located:
Definition
(d) Just below the leading edge.
Term
At positive angles of attack, a wing produces the most lift at:
Definition
(c) Just before the stall.
Term
An airplane is flying straight and level, therefore:
Definition
(d) Thrust equals drag, Lift equals weight.
Term
The term "Angle of Attack" is defined as:
.
Definition
(b) The angle between the wing chord line and the relative wind
Term
Weight acts:
Definition
(b) Always in line with gravity.
Term
When a fowler flap moves back:
Definition
(a) Wing area increases, camber increases.
Term
Where does lift act on a wing?
Definition
(d) Centre of Pressure.
Term
What does the "S" represent in the lift equation?
Definition
(c) Wing area
Term
Bernoulli's Theorem states:
(b)
Definition
When dynamic pressure increases, static pressure decreases.
Term
For a typical light training aircraft, the optimum angle of attack producing most lift for least drag is approximately:
(c)
Definition
+4.
Term
Wash out of a wing is:
(c)
Definition
A decrease in angle of incidence from root to tip.
Term
A symmetrical aerofoil section of a wing which is set at 0˚ angle of incidence will produce in level flight:
Definition
(d) Zero lift.
Term
The purpose of streamlining is:
(d)
Definition
To reduce pressure or wake drag.
Term
Drag is the force that resists ________.
(
Definition
a) Thrust
Term
3. At high speed the drag on an aircraft is mainly
Definition
(a) Parasite drag
Term
The speed of air at the surface of the wing (in boundary layer) is:
Definition
(a) Zero
Term
The best plan shape of a wing for minimum drag is:
Definition
(a) Elliptical
Term
What are the components of Total Drag?
Definition
(a) Lift induced drag and Parasite drag
Term
What are the two types of flow associated with the boundary layer?
Definition
(a) laminar and turbulent
Term
As airspeed increases, parasite drag
Definition
(a) Increases
Term
The additional drag resulting from the intersection of two parts of the airplane is called ________, and engineers design/install ________ to smooth out the flow of air at these intersections.
(a)
Definition
Interference drag, fairings
Term
An antenna of 0.05 sq. ft. of a cross-sectional area (S) produces 1 pound of drag in an airflow with a dynamic pressure (½ρv²) of 25 lbs/sq. ft. What is its drag coefficient? Drag = ½ρv² S Cd
(
Definition
a) .80
Term
If the landing gear is lowered:
(a)
Definition
Total drag increases.
Term
The minimum Total Drag of an aircraft in flight occurs:
(a)
Definition
At the speed where parasite drag and lift induced drag are equal.
Term
Lift induced drag (lift dependent drag) of an aircraft would be increased with:
Definition
(a) Increased weight.
Term
The boundary layer of a body in a moving airstream is:
(a)
Definition
A thin layer of air over the surface in which the air is retarded by the effects of friction.
Term
Skin Friction drag resulting from a laminar boundary layer will be:
(a)
Definition
Less than from a turbulent boundary layer.
Term
If speed is increased from 150 kts to 300 kts, the Pressure or wake drag due to shape will be:
Definition
Quadruple.
Term
The drag of an aircraft will:
(a)
Definition
Increase with an increase in air pressure.
Term
What phenomena causes Lift induced Drag?
Definition
(a) Wing tip vortices.
Term
What effect on lift induced drag does entering ground effect have?
Definition
(a) It decreases.
Term
When the undercarriage is lowered in flight:
(a)
Definition
Form drag will increase and the aircraft will pitch nose down.
Term
The point where the boundary layer changes from laminar flow to turbulent flow is called the;
Definition
(a) Transition point
Term
A high aspect ratio wing (High span to chord ratio, like a glider):
Definition
(a) Decreases lift induced drag.
Term
In straight and level flight, how does Parasite drag vary with airspeed?
(a)
Definition
V2 (directly with the square of the velocity)
Term
Wingtip vortices:
(a)
Definition
Right wing rotates anti-clockwise, left wing clockwise
Term
31. At low speed the drag on an aircraft is mainly
(a)
Definition
Lift Induced Drag
Term
32. The pressure gradient on the rear side of a shape where the air is flowing from Low static pressure to High static pressure is called;
(a)
Definition
Adverse pressure gradient
Term
33. The point where the air stops sticking to the shape of an object is called;
(a)
Definition
Separation point
Term
With regard to "P.L.A.N.n.", the acronym used to determine the capacity of a reciprocating engine to produce power, the "A" refers to what?
Definition
a) Cross sectional piston area
Term
. The final factor (n) in determining the capability of a reciprocating engine to produce power in the anacronym P.L.A.N.n. is:
a)
Definition
The number of cylinders of the engine
Term
The optimum angle of attack for a propellor blade to the airflow passing through it is approximately;
Definition
a) 4˚
Term
With regard to P.L.A.N.n., the pilot can control which of the factors in the cockpit?
a)
Definition
Mean cylinder pressure (P) by use of the throttle to control the amount of fuel and air being taken into the cylinders Engine Speed (N)
Term
A propellor blade ‘slips’ through the air unlike a woodscrew or corkscrew and so cannot be 100% efficient;
True or False?
Definition
True
Term
The pitch of a propeller blade that produces the most efficiency (most thrust for least drag) for a given speed is called;
Definition
a) Optimum angle of attack
Term
The resultant relative wind acting on a propellor, is the result of which two velocities?
Definition
a) Propellor’s rotational speed and aircraft’s forward speed
Term
. Which is faster;
a)
Definition
Propellor Tip speed
Term
9. In order to maintain a relatively constant angle of attack along the span of a propeller blade, blades are manufactured with what?
a)
Definition
Blade Twist
Term
Attempting to increase the top speed of an aircraft by fitting a bigger engine is difficult because;
a
Definition
) Parasite Drag increases as airspeed increases and a bigger engine creates more weight induced drag
Term
. Which equation(s) below is/are an expression of Newton's second law?
a)
Definition
Force = Mass x Acceleration
Term
In a variable propeller system, as airspeed increases, the propellor must ________ to maintain the most efficient angle of attack.
a
Definition
) Increase pitch
Term
. In the event of an engine failure (particularly important in a twin engined airplane) the propellor should automatically be turned to a minimum drag position, this is called:
Definition
a) Feathered
Term
What was the reason that the earlier engines had radially mounted cylinders?
Definition
a) Greater number of cylinders could be mounted and better cooling
Term
. Compared to jets, propellers move a ________ amount of air with a ________ acceleration.
Definition
a) Large/Small
Term
Which is considered the more "efficient" producer of "thrust"?
a)
Definition
Propeller driven by a reciprocating engine
Term
. A turbojet engine differs from a turbofan engine in that all of the air flows through the compressor section or the core of the engine, whereas some of the airflow with a turbofan engine flows around the outside of the core.
True or false?
Definition
True
Term
The term for the air which doesn’t pass through the core of a jet engine and get burnt with the fuel is called:
Definition
a) Bypass Air
Term
A propellor blade is twisted to ensure a constant angle of attack to the relative airflow along the blade which is moving faster through the air from the hub to the blade tip.
True or False?
Definition
True
Term
. 1 horsepower equals;
Definition
a) 550 foot pounds per second
Term
. Power =
Definition
a) Force x Velocity
Term
. A propellor accelarates a large mass of air with a relative small acceleration compared with a jet which accelerates a small mass of air with a very large acceleration;
True or False?
Definition
True
Term
27. The main factor that limits the diameter of a propellor blade is;
a)
Definition
The Speed of the blade tip relative to the speed of sound
Term
During the ground roll whilst accelerating along the runway before taking off, the four forces ________ in balance.
Definition
a) are not
Term
. The difference (in HP) between power avaliable and power required is called what?
Definition
a) Excess power
Term
. When determining takeoff distance required, whether runway is paved or grass will affect your takeoff distance.
True or False?
Definition
True
Term
The reasons for having more than a twin engine rather than one engine include which of the following?
Definition
a) To provide more power than can be provided by one engine.
a) Improves safety by providing redundancy in case one engine fails.
Both
Term
. The loss of one engine in a twin engine aircraft results in:
Definition
a) Significant loss of climb capability
a) Yaw in the direction of the failed engine
a) Increased drag due to use of rudder to overcome yaw
All of the above
Term
. The best glide ratio is:
Definition
a) found on power required curve at the point of minimum drag.
Term
WIth respect to change in velocity, what is required in order to generate enough lift to takeoff.
Definition
a) Acceleration
Term
Service ceiling is:
Definition
a) The maximum altitude in which the aircraft can achieve a climb rate of 100 fpm.
Term
. Best range airspeed with a tailwind will be ________ than best range airspeed with a headwind.
Definition
Lower
Term
22. Operating at maximum L/D (Lift/Drag ratio) gives speed for best glide distance and best range.
Definition
a) True
Term
. At airspeeds slower than V(min power), more power is required to maintain altitude. What is this called?
a
Definition
) Back side of the power curve
Term
. As altitude increases Power available;
Definition
a) Decreases
Term
. As aircraft weight increases Power required;
Definition
a) Increases
Term
. As Drag increases (from flaps and undercarriage lowered) Power required;
a)
Definition
Increases
Supporting users have an ad free experience!