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Flashcards in Aero Basic Theory 2-1 Deck (76):

Define Scalar

A quantity that represents only magnitude

Speed, Mass, Density, Volume, Power, Energy, Work, time, temperature

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Define Vector

A quantity that represents Magnitude and Direction.
Velocity, Force, Moment, Weight, Displacement, Acceleration,
Very Few Marines Will Do Anything


Define Mass

The Quantity of Molecular material that comprises and object.


Define Volume

The amount of space occupied by an object.


Define Density

Mass per unit volume.


Define Force

Mass X Acceleration.


Define Weight

The Force with which a mass is attracted toward the center of the earth by gravity.


Define Moment

Is created when a force is applied at some distance from an axis or fulcrum, and tends to produce rotation about that point.


Define Work

Is done when a force acts on a body and moves it.


Define Power

The rate of doing work or work done per unit of time.


Define Energy

Measure of a body’s capacity to do work.


Define Potential Energy

The ability of a body to do work because of its position or state of being.


Define Kinetic Energy

The ability of a body to do work because of its motion.


Explain, Newtons First Law.

Law of Equilibrium,
“A body at rest tends to remain at rest and a body in motion tends to remain in motion in a straight line at a constant velocity unless acted upon by some unbalanced force.”


Explain Equilibrium Flight.

Exist when the sum of all forces AND the sum of all moments around the center of gravity are equal to zero.

(A/C in straight and level flight at a constant velocity.)
(When these forces exactly cancel each other out.)
L+W=0 T+D=0


Explain Trimmed Flight.

Exist when the sum of all moments around the center of gravity is equal to zero.

(Sum of forces not equal zero)
(A/C @constant rate & constant angle of bank is Trimmed)
A/C in Equilibrium flight is in Trimmed Flight.


Explain Newtons Second Law.

Law of Acceleration.

“An unbalanced force(F) acting on a body produces an acceleration(a) in the direction of the force that is directly proportional to the force and inversely proportional to the mass(m) of the body.”
a = F/m


Explain Newtons Third Law.

Law of interaction.

“For every action, there is an equal and opposite reaction;
the forces of 2 bodies on each other are always equal and directed in opposite directions.”


Define Static Pressure.

The pressure particles of air exert on adjacent bodies,
Ambient Ps is equal o the weight of a column of air over a given area.
**force of Ps ALWAYS act perpendicular to any surface that the air particles collide with.


Define Air Density.

Total mass of air particles per unit of volume.
*Distance between individual air particles increase with altitude resulting in fewer particles per nit volume.
**air density decreases with an increase in Altitude.


Define Temperature.

Measure of the average random kinetic energy of air particles.

Decrease 2 C(3.57 F) per 1000ft until 36000ft.


Define Lapse Rate.

Rate of Temperature change.

2 C(3.57 F) per 1000ft until 36000ft
36000ft to 60000ft (T) remains constant -56.5 C(-69.7 F) —Isothermal Layer.


Define Humidity.

Amount of water vapor in the air.

**humidity increases, air density decreases.


Define Viscosity.

A measure of the air’s resistance to flow and shearing.

**Air - Temp. Increases, Air Viscosity increases.
**liquid- Temp. Increases, Viscosity decreases.


Define Local Speed of Sound.

The rate at which sound waves travel through a particular air mass.

**SOS in air, is dependent only on Temperature of the air.
***Temperature increases, SOS Increases.


Define Standard Atmosphere.

Engineering Baseline.
Static Pressure - 29.92 in.Hg & 1013.25 mbar
Temperature - 59 F & 15 C


Describe General Gas Law
Static Pressure, Air Density, Temperature, Altitude

P = pRT (P-pressure, p-density, T-temperature)

***increase in temperature,decrease in density and vice versa


Explain Bernoulli’s Equation

The sum of Static Pressure(ps) and Dynamic Pressure(q)
ps- pressure particles of air exert on adjacent bodies, wt of column of air over a given area.
q-=1/2pV^2, measure of impact pressure of air moving together.
H = ps + 1/2pv^2 or H = ps + q


Define Steady Airflow.

Exist at every point in the airflow Static Pressure, Density(p), Temp, Velocity remain constant over time. Velocity of every particle that passes ANY Given Point is always the same.
*Air particles follows the same path as the preceding particle.


Define Streamline.

The path that air particles follow in a STEADY Airflow.

**In steady airflow, particles do not cross streamlines.


Define Streamtube.

A collection of many adjacent streamlines, which contains a flow just as effectively as a tube with solid walls.
A1V1 = A2V2


Explain Continuity Equation.

A1V2 = A2V2

Mass Flow Rate - M = pAV.


Define Indicated Altitude.

Indication on a pressure altimeter when the Kollsman Window is set to the current Local altimeter setting.


Define Above Ground Level altitude.

The height of the aircraft above he terrain it is flying.
*Absolute Altitude.


Define Mean Sea Level.

Actual heigh above MSL
*True Altitude.

***MSL= Pressure Altitude(PA) at Standard Atmosphere.


Define Pressure Altitude.

The Height above the Standard Datum Plane.

**SDP-actual elevation at which the BPessure of 29.92inHG
***SDP=Sea Level I Standard Atmosphere —>
True Altitude will be equal to pressure altitude.


Define Density Altitude.

The Altitude in the Standard Atmosphere where the Air Density is equal to Local Air.
(Correct Press ATM for Humidity from STD ATM.)
*STD ATM, Density = Pressure Altitude.
**High DA = Low air density.
***not a reference of height but of A/C Performance.


Describe the Pitot-Static System

System to measure airspeed, velocity and Dynamic pressure.
Consist of Pitot tube the senses total pressure(H), Static port to sense s static pressure(Ps)and a Differential gauge.
q=H-Ps // Used to Measure Total Pressure. (H=Ps+(1/2pV^2)


Define Indicated Airspeed

Instrument Indication of the Dynamic Pressure.
**errors due to installation, Altitudes, give variances b/w instrument and actual flight speed.


Define Calibrated Airspeed.

Indicated Airspeed Corrected for Instrument Error.

**Inst. Error.-due to physical location of static port, when operated through all AOA Ps distribution varies for position error.


Define Equivalent Airspeed.

True Airspeed at sea level on a STD Day that produces the same dynamic pressure as the actual flight condition.
*Found by Correcting Calibrated Airspeed for Compressibility error.
**Compressibility-ram effect in pitot resulting in high tear than normal airspeed indication when approaching SoS.


Define True Airspeed.

Actual Velocity at which the airplane moves through air mass.
**Found by correcting Equivalent A/S b/w local air density and density of the air at sea level on STD day.
**TAS = IAS only on STD,
***Constant IAS - TAS will increase 3 KTS per 1000FT
& Climbing from sea level = TAS must increase.


Define Ground Speed.

Airplanes Actual Speed over ground.
**TAS is through air mass corrected for HW/TW = GS.


Describe Factors affecting Airspeed.

I - Indicated —-> corrected for instrument—>
C - Calibrated —>Corrected for Compress —>
E - Equivalent —>corrected for density—>
T - True. —>corrected for HW or TW—>
G - Ground


Define an Aircraft.

Any Device used or intended to be used for flight in the air. Normally supported either by the buoyancy(balloon) of the structure or by dynamic reaction of the air against its surfaces(helo or airplane).


Define an Airplane.

A mechanically driven fixed wing aircraft, heavier than air, which is supported by the dynamic reaction of the air against its wings.

**T-6B - Single Turboprop engine


Describe the 5 Components of an airplane.

Landing Gear


State the Advantages of the Semi-Monocoque Fuselage.

Modified version of monocoque, having skin, Transverse Frame members and stringers which all share in stress loads and may be readily repaired if damaged - T6B.


Define Full Cantilever Wing construction.

All Bracing is internal of wings, -T6B.


Describe the 3 airplane Axis reference system.

Longitudinal - nose to tail, movement around = Roll
Lateral - Wingtip to Wingtip, movement around = Pitch
Vertical - through Center of Gravity, movement around = Yaw
***CG - point at which all WT is concentrated and forces/moments are measured. Axis’s are Referenced to the CG.


Define Chord Line.

An infinitely long, straight line which passes through its leading and trailing edges.


Define Chord.

The precise measurement between the leading and trailing edges measured along the Chord Line.
*typically vary from the wingtip to wing root.


Define Root Chord.

The Chord at the Wing Centerline.


Define Tip Chord.

The Chord measured at the wingtip.


Define Average Chord.

The average of every Chord from the wing root to the wingtip


Define Mean Camber Line.

Is a line halfway between the upper and lower surface of an airfoil.


Define Symmetric Airfoil.

An airfoil with Zero Camber with MCL and the Chord line are the same and produces no lift at Zero AOA.


Define Positive Camber.

An airfoil has the MCL above the Chord Line and produces lift at Zero AOA.


Define Negative Camber.

An airfoil has the MCL below the Chord Line and will produce Negative lift at Zero AOA.


Define Spanwise Flow.

Airflow that travels along the span of the wing, parallel to the leading edge.
Flows normally from the Root to the Tip.
This airflow is not accelerated over the wing and therefore produces no lift.


Define Chordwise Flow.

Air flowing at right angles to the Leading edge of an airfoil.
Chordwise flow is the only flow that accelerates over a wing, the only airflow that produces lift.


Define Pitch Attitude.

The angle between an airplane’s longitudinal axis and the horizon.


Define Flight Path.

The path described by its CG as it moves through an air mass.


Define Relative Wind.

The airflow the airplane experiences as it moves through the air.
Equal in magnitude and opposite in direction to the flight path.


Define Angle of Attack.

The Angle between the relative wind and the Chord Line of an Airfoil.


Define Angle of Incidence.

The Angle between the airplane’s Longitudinal Axis and the Chord line of the wing.


Define Dihedral Angle.

The angle between the Spanwise Inclination of the wing and the Lateral Axis.(upward slope of the wing when viewed from the front

**Anhedral = negative dihedral angle.
**T6B - dihedral to improve lateral stability.


Define Wingspan.

The length of a wing, measured from wingtip to wingtip. Refers to the entire wing.
*T6B -33’5”.


Define Wing Area.

The apparent surface area of a wing from wingtip to wingtip. Includes area within outline of the wing - fuselage, hull.



Define Wing Loading.

The rat of an airplane’s weight to the surface area of its wings.
**an inverse relationship between aspect ratio and wing loading.



Define Taper Ratio.

The ratio of the Tip Chord to the Root Chord.



Define Sweep Angle.

The Angle between the lateral axis and a line drawn 25% aft of the Leading Edge.

Sweep Angle is not parallel to the Leading Edge on a Tapered Wing.
*Wing Sweep affects Max Lift and Stall Characteristics
**T6B - Swept


Define Aspect Ratio.

The ratio of the wingspan to the Average Chord.
(AR) = b/c

**high aspect - Glider, low aspect - jet.


Define Center of Gravity.

The point at which all weight is considered to be concentrated and about which all forces and moments are measured.

**will balance if suspended at the CG and may move due to ordinance or fuel burn.


Define Aerodynamic Center.

The point along the Chord line around which all changes in the Aerodynamic Force take place.
*approx. (1/4) or 23-27% of the length of the chord from the leading edge.
**remains stationary unless the airflow over the wings approach SOS.


Describe the Pitot-Static System

System to measure airspeed, velocity and Dynamic pressure.
Consist of Pitot tube the senses total pressure(H), Static port to sense s static pressure(Ps)and a Differential gauge.
q=H-Ps // Used to Measure Total Pressure. (H=Ps+(1/2pV^2)