Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Flying > Aerodynamics > Flashcards

Aerodynamics Flashcards

1
Q

Atmospheric Composition

A
  • 78% Nitrogen
  • 21% Oxygen
  • 1% other trace gases

*most of atmospheres oxygen is contained below 35000 ft.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Standard Temperature and Pressure

A
  • 15C
  • 59F
  • 29.92 inches of mercury
  • 1013.2 mb
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Standard Lapse Rates

A
  • Temp- 2 degrees per 1000 ft
  • Pressure- 1” Hg per 1000 ft
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Pressure Altitude

A
    • height above the standard datum plane
    • theoretical altitude where atmosphere is 29.92

*can be determined

    • setting altimeter to 29.92 and reading
    • reported altimeter setting minus 29.92
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Density Altitude

A
  • pressure alt. corrected for non standard temperature
  • less dense air = higher density altitude
  • high density altitude = poor aircraft performance
    • less power because engine takes in less air
    • less thrust because prop is less efficient in thin air
    • less lift because thin air exerts less force
  • aircraft performs as though it were at density altitude
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Magnus Effect

A
  • german physicist who used cylinders in a fluid to help explain the theory of lift
    • flowing air around a non rotating cylinder is equal on the top and bottom
    • rotating cylinder in a motionless fluid - fluid affected by viscosity and skin friction
    • fluid is near motionless on the surface of cylinder. molecules moving clockwise with the cylinder. due to viscosity increase in fluid motion in the clockwise direction
  • when the air is moving along with the cylinder there is an even higher circulatory flow
  • higher velocity on top and low on the bottom
  • low pressure on top produces upward force known as Magnus effect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Bernoulli’s Principle

A
  • as velocity of a moving fluid increases the pressure decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an airfoil?

A
  • structure designed to obtain a reaction upon its surface when air passes over it
  • designed to produce lift
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Chord Line

A
  • imaginary line drawn from the leading most edge to trailing most edge of an airfoil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4 Factors Acting on an Aircraft

A
  • Thrust- forward force produced by the power plant
  • Drag- rearward retarding force caused by disruption of airflow by the wing, fuselage, and other protruding objects
  • Weight- combined load of aircraft being pulled down by gravity
  • Lift- produced by dynamic effect of air over an airfoil. opposes downward force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Angle of Attack

A
  • the acute angle between the chord line of the airfoil and the relative wind
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Angle of Incidence

A
  • angle between wing chord line and longitudinal axis of aircraft
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Relative Wind

A
  • acts parallel and opposite the flight path of the airfoil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Parasite Drag

A
  • Form- drag due to the aircraft’s shape and airflow around it (cowlings, antennas, etc.)
  • Interference- drag due to the intersection of airstreams that create eddy currents, turbulence, or restricts smooth airflow (90 degree angles/ wing root & fuselage)
  • Skin Friction- aerodynamic resistance due to contact of moving air with the surface of the aircraft
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Induced Drag

A
  • no system is perfect. It is the drag produced as a byproduct of lift
  • wingtip vorticies are an example (greatest when heavy, clean, and slow)
    • air from under wings wraps around wingtips and spirals backwards
    • can be reduced with winglets
  • as AOA increases induced drag increases
  • as airspeed increases induced drag decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ground Effect

A
  • When an aircraft comes within several feet of the ground a change in the 3 dimensional flow pattern around the aircraft
  • alters the wings upwash, downwash, and wingtip vorticies
  • due to the ground surface with the airflow patterns about the aircraft
  • reduces induced AOA and induced drag
  • wing will require lower AOA to produce same lift
  • plane will fly at slower speed
17
Q

Aircraft Axes

A
  • Lateral- pitching (stabilator, elevator)
  • Longitudinal- rolling (ailerons)
  • Vertical- yawing (rudder)
18
Q

Static Stability

A
  • initial tendency of aircraft after it is disturbed from equilibrium (short-term)
  • Positive- aircraft moves toward initial position it was in before it was disturbed
  • Neutral- aircraft remains in new position after disturbed
  • Negative- aircraft continues away initial position it was disturbed from
19
Q

Dynamic Stability

A
  • Aircraft’s response over time (long-term)
  • Must have positive static stability in order to have any type of dynamic stability
  • Positive- motion decreases in amplitude and returns to equilibrium state
  • Neutral- motion neither increases or decreases in amplitude
  • Negative- motion increases and becomes more divergent
20
Q

Maneuverability vs. Controllability

A
  • Maneuverability- quality of the aircraft that permits it to be maneuvered easily and to withstand the stresses imposed by maneuvers
  • Controllabilty- capability of an aircraft to respond to the pilot’s control, especially with respect to flight path and attitude.
21
Q

Wing Dihedral

A
  • wings angled into a slight “V” (1 to 3 degrees)
  • when an aircraft is banked without turning, it has a tendency to sideslip or slide downward. the lower wing has a greater AOA = more lift and wing rises back up
  • too much dihedral = too stable = resistance to roll
22
Q

Wing Sweepback

A
  • aircraft that drops a wing, the low wing presents a leading edge at an angle perpendicular to the relative wind = more lift = wing rises
  • on a straight wing the relative wind hits at 90 degrees most of the time
  • sweepback has the effect of persuading the wing into believing that it is flying slower than it really is so formation of shockwaves is delayed. delays the onset of compressability effects.
23
Q

Keel Effect

A
  • aircraft acts like a weathervane and returns to a stable condition
    • greater portion of keel area is above and behind the CG
24
Q

Dutch Roll

A
  • coupled lateral/direction oscillations
  • aircraft makes a figure-8 on the horizon
  • outside wing has higher speed so more lift then more drag to bring it back
25
Q

Stall

A
  • rapid decrease in lift couse by separation of airflow brought on by exceeding critical AOA
  • can occur at any pitch attitude or airspeed
  • wing does not totally stop producing lift, just not enough to maintain altitude
26
Q

Wing Twist

A
  • Wing is twisted to have a higher AOA at the root than it does at the tip
  • Will stall at the root first so the pilot will still have aileron control at the wingtips
27
Q

Propeller Twist

A
  • Outer portions of the blade travel faster than the portions near the hub
  • Twisting permits the propeller to operate at a relatively constant AOA along its length in cruising flight
28
Q

Turning Tendency

-Torque

A
  • as the internal engine parts and propeller are revolving in one direction an equal force is trying to rotat the aircraft in the opposite direction
    • correction is to offset the engine and use opposite rudder
29
Q

Turning Tendency

-Corkscrew Effect

A
  • Spiraling Slipstream
  • High-speed rotation of an aircraft propeller gives a corkscrew or spiraling rotation to the slipstream
  • Strikes the vertical fin and causes the plane to turn around the vertical axis
  • As speed increases the spiral elongates and becomes less effective
30
Q

Turning Tendency

-Gyroscopic Action

A
  • Precession
  • When a force is applied to deflect the propeller out of its plane of rotation, the resulting force is 90 degrees ahead and in the direction of rotation
31
Q

Turning Tendency

-P Factor

A
  • When an aircraft is flying with a high AOA, the bite of the downward swinging propeller blade is greater than the bite of the upward moving blade
  • Moves the center of thrust to the right of the prop disk area, causing a yawing movement toward the left around the vertical axis
32
Q

Load Factor

A
  • ratio of the maximum load an aircraft can sustain to the gross weight of the aircraft
  • measured in G’s
  • force of stress on an airplane structure when it is not flying in a straight line
  • 60 degrees of bank = 2Gs
33
Q

Limit Load Factor

A
  • Normal- 3.8 to -1.52
  • Utility- 4.4 to -1.76
  • Acrobatic- 6 to -3
34
Q

Forward Loading

A
  • “heavier” = slower
  • requires a higher AOA of the wing, which results in more drag, and in turn produces a higher stall speed (closer to crititcal AOA)
35
Q

Aft Loading

A
  • wing is relieved of wing loading an less lift is required to maintain altitude
  • required AOA is less, so drag is less, allowing for a faster cruise speed
  • less controllable at slow flight as the CG is moved aft
  • stall could lead to loss of control because not enough forward force to overcome CG being behind CL
36
Q

Boundary Layer

A
  • Layer of air over the wings surface that is slowed by viscosity and skin friction
  • Laminar
    • very smooth flow
    • less stable
    • layer gets thicker as distance increases from leading edge
  • Turbulent
    • at some distance back from the leading edge the smooth laminar flow breaks down and transitions into turbulent flow
    • the further back the turbulent layer starts the better
37
Q

Separation

A
  • occurs when the airflow breaks away from an aifoil
  • produces high drag and destroys lift
  • moves forward as AOA is increased

laminar boundary layer than turbulent then separation

Flying (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions