AERT 4040 Flashcards by Megan Schittenhelm

Density Altitude is used as a predictor of aircraft performance, not as a height reference.
True
False

True

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An aircraft’s Mach Number is the aircraft’s

Local Speed of Sound divided by TAS

IAS divided by the Local Speed of Sound

TAS divided by the Local Speed of Sound

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The temperature and pressure conditions for a standard day are ______________.

59 degrees F / 15 degrees C and 29.92 in of Hg / 1013 mbar

There is no such thing as a standard day

68 degrees F / 20 degrees C and 30.30 in of Hg / 1026 mbar

59 degrees F / 15 degrees C and 29.92 in of Hg / 1013 mbar

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What did the Wright brothers think was the most difficult problem, thus the first problem they attacked when building their Flyer?

Design of the wings

How to control and balance the aircraft

Developing a means of propulsion

How to control and balance the aircraft

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Density is

is always expressed by Liters per Pound

Mass per unit volume

Weight per unit volume

Mass per unit volume

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The Critical Mach Number of an aircraft is the highest Mach Number the aircraft can travel before structural damage is done to the airframe.
True
False

False

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How did the Wrights correct their problem of roll reversal?

They used a canard rather than an elevator

They used counter-rotations propellers

They developed a movable rudder and connected it to the roll control

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What method did the Wright brothers use to control roll?

The used what was later called flight spoilers

They developed a technique of wing warping

They developed ailerons

They developed a technique of wing warping

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The speed of sound in air is dependent upon the

Air Density only

A combination of Air Temperature, Air Density and Humidity

Air Temperature only

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What was unique about the engine that the Wrights used for their Flyer?

It was the first time aluminum was used in the construction od an aircraft

It was the first use of 100 LL fuel

It was the first use of a six cylinder engine

It was the first time aluminum was used in the construction od an aircraft

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Air viscosity __________ as the air temperature increases.

Increases

Stays the same

Decreases

increases

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Total pressure is:

measured parallel to the local stream

1/2ρV²

static pressure minus dynamic pressure

static pressure plus dynamic pressure

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The General Gas Law sets the relationship between three properties of air: pressure (P), density (ρ), and temperature (T). It is expressed as an equation where R is a constant for any given gas. What is the correct expression of the General Gas Law.

ρT = PR

ρP = RT

ρ = P/RT

ρPT =

ρ = P/RT

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The Law of Interaction states __________.

“Two opposite forces cannot interact.”

“An unbalanced force acting upon a body produces an acceleration in the direction of the force that is directly proportional to the force and inversely proportional to the mass of the body.”

“A body at rest tends to stay at rest.”

“For every action there is an equal and opposite reaction.”

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The angle of incidence of a wing is the angle between a line drawn through the 25% cord points and a line drawn parallel to the lateral axis.
True
Fasle

False

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Static pressure acts:

in the direction of the flow

perpendicular to the surface that any air molecules collide with.

perpendicular to the direction of flow

in the direction of the total pressure

perpendicular to the surface that any air molecules collide with.

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A moment is _________.

created when a force is applied at some distance from an axis or fulcrum, producing rotation about that point

the result of mass x acceleration

a body’s capacity to do work

the force with which a mass is attracted toward the center of the earth

created when a force is applied at some distance from an axis or fulcrum, producing rotation about that point

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The center of gravity is the point at which __________.

lift is generated

all weight is concentrated

all aerodynamic forces are concentrated

elevator authority is lost

all weight is concentrated

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Wing Loading is:

the aircraft weight divided by the sine of the wing dihedral

the ratio of the aircraft weight to the surface area of the wing

the ratio of the aircraft weight to the wing span

the ratio of the aircraft weight to the volume of the wing

the ratio of the aircraft weight to the surface area of the wing

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The Mean Camber Line:

is a line drawn halfway between the wing root and the wing tip/

is the line drawn perpendicular to the aerodynamic center of the wing

is a line drawn halfway between the leading edge and trailing edge of the wing

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

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The chord of an airfoil is defined as ___________.

an infinitely long line drawn through the leading and trailing edges of an airfoil

a measure of the wing along the chord line, from the leading edge to the trailing edge

the angle between the longitudinal axis and the horizon

the length of a wing

a measure of the wing along the chord line, from the leading edge to the trailing edge

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

F = ma

a = Fm

m = Fa

F = m/a

F = ma

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The angle of attack of a wing is the angle between the wing’s cord and the horizon
True
False

False

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The axis is which the aircraft nose moves left or right about the center of gravity
pitch
yaw
center
roll

yaw

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The camber of an airfoil: is the average distance between the cord and the mean camber line measured perpendicular to the cord is expressed as a percentage of the wing surface area. is the maximum distance between the cord and the mean camber line measured perpendicular to the cord is the distance between the cord and the mean camber line measured at the aerodynamic center of the wind

is the maximum distance between the cord and the mean camber line measured perpendicular to the cord

Aspect Ratio of a wing is the ratio of the wingspan to the average cord the ratio of the average cord to the camber the ratio of the wing surface area to the average cord the ratio of the wing surface area to the wingspan

the ratio of the wingspan to the average cord

A _________ airfoil produces lift at zero degrees angle of attack. symmetric tapered dihedral positively cambered

positively cambered

What does sweeping a wing back do to CLMAX Slightly decreases CLMAX and increases Stall AOA Slightly increases CLMAX and increases Stall AOA Slightly decreases CLMAX and decreases Stall AOA Slightly increases CLMAX and decreases Stall AOA

Slightly decreases CLMAX and increases Stall AOA

Aspects of which two laws seem to contribute to the production of lift? Ohm's Law and the Heisenberg Uncertainty Principle Bernoulli's Law and Newton's Third Law of Motion Pascal's Law and Bernoulli's Law General Gas Law and Newton's Second Law of Motion

Bernoulli's Law and Newton's Third Law of Motion

Velocity and AOA are ____________ related in level flight Directly Not at all Inversely

inversely

The AOA which produces CLMAX is called the: Best rate of climb AOA Stall AOA Best Angle of Glide AOA Best Angle of Climb AOA

Stall AOA

As the AOA increases, the center of lift ___________. Moves rearward Moves forward Stays Stationary

moves forward

When an aircraft flies more slowly, more AOA is needed, when it flies faster less AOA is needed true false

true

L/DMAX is the point where . drag is the greatest the ratio of lift to drag is the greatest the stall angle of attack is reached lift is the greatest

the ratio of lift to drag is the greatest

Which factors are accounted by the Coefficient of Lift? Velocity Angle of Attack Aspect Ratio Camber Surface area of the wing Viscosity Air Density Compressibility

AOA Velocity Camber Compressibility Aspect Ratio

AOA is the most important factor in the CL and the easiest for the pilot to change true false

true

The Center of Pressure is the point on the wing where the vectors of lift and drag act true false

true

What are the factors that affect lift? Compressibility Air Density Viscosity Dihedral Angle Mean Cord Length Aspect Ratio Angle of Attack Surface area of the wings Velocity Camber

Compressibility air density viscosity aspect ration angle of attack surface area of the wings velocity camber

Ground Effect __________. Drastically increases lift available Reduces the interference drag of the landing gear Reduces the low pressure wake which causes form drag Blocks the effect of Induced Drag

Blocks the effect of Induced Drag

When does ground effect start becoming a factor? 50 feet AGL one wingspan above the ground two wingspans above the ground 100 feet AGL

one wingspan above the ground

Drag that is produced simply due to the production of lift is called ________. Interference Drag Form Drag Induced Drag Viscous Drag

induced drag

Parasite drag is ___________. the component of drag associated with the production of lift minimized by installing winglets, wingtip fuel tanks or missile rails greatest at low airspeeds made up of form, friction, and interference drag

made up of form, friction, and interference drag

Streamlining shapes and increasing _________ are useful methods of reducing form drag. Angle of Attack Viscous Drag Velocity Frontal Area

Viscous Drag

Total drag is composed of ____________. upwash and downwash form and interference drag parasite and induced drag thrust and lift

parasite and induced drag

Which of these are true about L/D Max - Any movement away from L/D Max airspeed will increase total drag - L/D Max AOA produces minimum total drag - L/D Max AOA corresponds to the aircraft's maximum speed - At L/D Max, induced and parasite drag are equal to each other. - The maximum amount of lift that an aircraft can produce occurs at L/D Max AOA

Any movement away from L/D Max airspeed will increase total drag L/D Max AOA produces minimum total drag At L/D Max, induced and parasite drag are equal to each other.

Drag that is created by airflow separating from the surface of an object and the low pressure wake that is created by that separation is called __________. Interference Drag Form Drag Viscous Drag Induced Drag

form drag

Drag that is created by mixing airstreams between components is called _________. Form Drag Interference Drag Viscous Drag Induced Drag

Interference Drag

An increase in weight or altitude will ____________ L/D Max airspeed but will ___________ L/D Max AOA. decrease / not affect decrease / increase increase / not affect increase / decrease

increase / not affect

Accelerating the air that surrounds a moving object requires force, thus creating drag. This is an example of _________ drag. Form Drag Interference Drag Induced Drag Viscous Drag

Viscous Drag

In a jet aircraft, as velocity increases, thrust available _________. Decreases Stays the same Increases

stays the same

With a variable pitch prop, what instrument in the cockpit is used to represent power? Prop Pitch Engine Exhaust Temperature Shaft Torque PRM

shaft torque

An increase in aircraft weight will shift the thrust required and power required curves down and to the right up and to the left down and to the left up and to the right

up and to the right

A thrust required curved can be use for various, weights, altitudes and configurations. true false

false

Lowering an aircraft's landing gear will shift the thrust required and power required curves up and to the right straight up up and to the left straight down

straight up

What are the five basic types of jet engines? Centrifugal Flow Engine Water Injected Engine Ramjet Engine Rocket Assisted Engine Radial Flow Engine Turbofan Engine Circular Flow Engine Axial-Centrifugal Compressor Engine

- Axial-Centrifugal Compressor Engine - Centrifugal Flow Engine - Turbofan Engine - Radial Flow Engine - Ramjet Engine

In equilibrium flight, thrust must ____________ drag. be less than be equal to be greater than

be equal to

Torque and P-Factor both affect how propeller aircraft fly. What effect to each have on aircraft The both create a yawing motion Torque creates a rolling motion, P-Factor creates a yawing motion. They both create a rolling motion Torque creates a yawing motion, P-Factor creates a rolling motion

Torque creates a rolling motion, p-factor creates a yawing motion

For a propeller driven aircraft, max excess power occurs at L/D Max airspeed A speed less than L/D Max A speed greater than L/D max

L/D max airspeed

For a jet, power available increases linearly with an increase of velocity. true false

true

Since aircraft designers wish to minimize the effects of P-Factor, they align the thrust axis with the relative wind for cruise airspeeds. Thus, P-Factor will be most prevalent at AOAs significantly different from cruise AOA. true false

true

How do you locate L/D Max for a propeller driven aircraft on a Power Required (Power vs. Velocity) Curve Draw a straight line starting at the origin of the graph and tangent to the curve. The tangent point is L/D Max. L/D Max occurs where the slope of the graph is equal to one L/D Max occurs five knots slower than the lowest point on the graph L/D Max is the lowest point on the graph

Draw a straight line starting at the origin of the graph and tangent to the curve. The tangent point is L/D Max.

For a propeller driven aircraft, max excess thrust occurs at L/D Max Airspeed A speed greater than L/D Max a speed less than L/D Max

a speed less than L/D Max

Output from an engine in a propeller driven aircraft is called Shaft Horsepower Centrifugal Horsepower Brake Horsepower Thrust Horsepower

Shaft Horsepower

Slipstream swirl is the most noticeable at high power settings at high airspeed low power settings at low airspeed high power settings at low airspeed low power settings at high airspeed

high power settings at low airspeed

Maximum power available occurs at the full throttle setting. true fasle

true

For both jet and propeller driven aircraft, as air density decreases, thrust ________. Increases Stays the same Decreases

Decresases

Output from a propeller is called Shaft Horsepower Brake Horsepower Thrust Horsepower Centrifugal Horsepower

Thrust Horsepower

Propeller Efficiency is determined by Thrust Horsepower divided by Shaft Horsepower true false

true

For a turbojet, max excess thrust occurs at _________________. At a speed less than L/D Max At a speed greater than L/D Max L/D Max Airspeed

L/D Max Airspeed

In a propeller driven airplane, as velocity increases, thrust available ______. Decreases Stays the same Increases

decreases

For a turbojet aircraft, max excess power occurs at L/D Max airspeed A speed greater than L/D Max A speed less than L/D Max

A speed greater than L/D Max

Power on stall speed will be _______________ power off stall speed faster than the same as lower than

lower than

The only reason an aircraft stalls is because The only reason an aircraft stalls is because the wings have exceeded the stalling pitch angle the aircraft has slowed below Vstall Thrust required exceeds thrust available the wings have exceeded the stalling angle of attack

the wings have exceeded the stalling angle of attack

What is the only thing that needs to be done to recover from a stall? What is the only thing that needs to be done to recover from a stall? Increase thrust available to over thrust required Lower the aircraft's nose below the horizon Decrease the AOA below the stalling angle of attack Increase the aircraft's speed to greater than Vstall

Decrease the AOA below the stalling angle of attack

The slotted flap is more advantageous than a plain flap because air passing through the slot aids in boundary layer control true false

true

Different things can be done to the design to a wing to give it good stall characteristics. The most common of these techniques are Different things can be done to the design to a wing to give it good stall characteristics. The most common of these techniques are Geometric wing twist Installation of a stall strip Installation of vortex generators Installation of a wing fence Aerodynamic wing twist

Aerodynamic wing twist Geometric wing twist Installation of a stall strip

The most desirable stall pattern of a wing is one where the wing starts to stall at the wingtip and moves inboard. true false

false

Most slats increase lift by increasing the wing's camber true false

false

Swept wings are used on high speed aircraft because they reduce drag and allow the aircraft to fly at higher mach numbers. Swept wings stall at the root first and progresses rapidly outward across the rest of the wing. true false

false

When flaps are lowered, the pilot should raise the nose due to the increase drag of the flaps lower the nose due to the increased drag of the flaps attempt to keep his flight attitude the same lower the nose to keep the increase of lift from ballooning the aircraft

lower the nose to keep the increase of lift from ballooning the aircraft

Fowler flaps are very effective high lift devices because they increase the camber of the wing They increase the aspect ratio of the wing The have several slots so they aid in boundary layer control since they move aft, they also increase the surface area of the wing

The have several slots so they aid in boundary layer control since they move aft, they also increase the surface area of the wing they increase the camber of the wing

As a stall progresses, the _________ lose control effectiveness first, followed by the ________ and then finally the _________. ailerons, rudder, elevators rudder, ailerons, elevators elevator, ailerons, rudder ailerons, elevators, rudder

ailerons, elevators, rudder

The two common types of high lift devices Increase camber Delay boundary layer separation Increase the angle of attack Increase the aspect ratio

Increase camber Delay boundary layer separation

Rectangular wings are limited to low speed, light weight construction where simplicity of construction and good stall characteristics are the predominant requirements true false

true

Erect spins are either unaccelerated or accelerated. What control input will make a spin unaccelerated? Rudder in the direction of spin Full forward stick/yolk Full aft stick/yolk Ailerons against the direction of spin

Full aft stick/yolk

How can you tell the difference between a spin and a spiral? Airspeed Roll rate Rate of descent Pitch attitude

Airspeed

It is impossible for an aircraft to enter an inverted spin True False

False

What two things do you need for a spin The aircraft's CG must be in the aft half of the flight envelope The elevator must be trimmed nose down A stalled aircraft Some sort of yawing force must be present

A stalled aircraft Some sort of yawing force must be present

A spin is an aggravated stall that results in autorotation True False

True

Slow activation of the elevators during the spin allows the spin to accelerate. This makes for a much easier and smoother recovery true false

false

What keeps the spin goin? The P-Factor from the engine Due to the yawing motion, the wings are not symmetrically stalled. Gyroscopic precession caused by the engine or prop Any difference in wing fuel quantity

Due to the yawing motion, the wings are not symmetrically stalled.

Poststall gyrations are dependent upon an aircraft's _________. weight airspeed CG G loa

airspeed

An aircraft's spin axis is always located in the center of the fuselage at the 50% cord line. true false

false

What is usually the most effective control for stopping the autorotation Rudder Elevators Aileron

Rudder

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AERT 4040 Flashcards

Aerodynamics

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