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Aviation Whatnot > Fundamentals of Flight > Flashcards

Fundamentals of Flight Flashcards

FM 3-04.203

1
Q

What are Newton’s three laws of motion?

A

Interia, Acceleration, and Action/Reaction

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2
Q

What does Newtonat ‘s law of Inertia state?

A

A body at rest will stay at rest and a body in motion will stay in motion (in the same speed and direction) unless acted on by an external force.

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3
Q

What does Newton’s law of Acceleration state?

A

The force required to produce a change in motion of a body is directly proportional to its mass and rate of change in its velocity.

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4
Q

What does Newton’s law of Action/Reaction state?

A

For every action, there is an equal and opposite reaction.

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5
Q

What is Bernoulli’s Principle?

A

It is the Law of Conservation of Energy - energy can not be created or destroyed; it can only be transferred.

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6
Q

How does an airfoil create lift?

A

The pressure difference between the upper and lower half of the airfoil. Air has to cover a greater surface area over the upper half - therefore, there is less static pressure on the upper half and more on the lower half. This creates about 75% of the aerodynamic force.

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7
Q

What is relative wind?

A

It is the result of movement of an airfoil through the air.

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8
Q

What is rotational relative wind?

A

It is created by the rotation of rotor blades as they turn about the mast.

Rotational Relative Wind flows opposite of the physical flight path of the airfoil and the velocity is highest at the tip.

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9
Q

What is induced flow?

As the helicopter gains forward airspeed, what happens to induced flow velocity?

A

Also known as downwash, it is the result of the rotor blade changing still air into a column of descending air.

It decreases.

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10
Q

What is resultant relative wind?

What does it serve as the plane of reference for?

A

It is rotational relative wind modified by induced flow.

It also serves as the plane for development of TAF.

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11
Q

What is the angle of incidence?

Is it a mechanical or aerodynamic angle?

A

It is the angle between the chordline and the roational relative wind of the rotor system.

Mechanical.

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12
Q

What is the angle of attack?

Is it a mechanical angle or aerodynamic?

A

It is the angle between the chordline and resultant relative wind.

Aerodynamic

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13
Q

What are the three types of drag?

A

Profile, parasite, and induced drag.

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14
Q

What is profile drag?

A

It is drag produced from the frictional resistance of the blades moving through the air. It increases moderately at high speeds and rapidly with the onset of blade stall or compressability.

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15
Q

What is induced drag?

A

It is drag that is the result of the production of lift. It exists between the axis of roation and lift.

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16
Q

What is parasite drag?

A

It is drag produced from non-lifting portions of the aircraft. It is the greatest force acting on the aircraft at high airspeeds.

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17
Q

What is Max Range airspeed?

A

The airspeed at which total drag is its lowest.

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18
Q

Describe the torque reaction and the anti-torque tail rotor.

Which of Newton’s laws applies?

What is the effect of not applying enough pedal during any situation?

A

Torque reaction is the helicopers tendancy to rotate clockwise due to the counterclockwise rotation of the main rotor. The anit-torque tail rotor prevents the fuselage from rotating clockwise by providing counterclockwise force.

Newton’s law of equal/opposite reaction.

The helicopter will turn in the direction of torque (clockwise).

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19
Q

The balance of forces relates to what?

A

Newton’s law of acceleration - the force required to produce a change in motion is directly proportional to its mass and rate of change in its body (Total residual force vs weight and parasite drag).

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20
Q

Describe the balance of forces at a stationary hover.

A

Total resultant force (up) equals weight (down), therefore the helicopter remains in a stationary hover.

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21
Q

Descrive the balance of forces during accelerated flight.

A

Total resultant force begins to move in a direction while weight remains downward. Parasite drag will begin to develop as airspeed is increased.

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22
Q

Describe the balance of forces during steady-state flight.

A

Total resultant force (lift and thrust) are equal to the force of weight and parasite drag. Acceleration will continue until the two opposing forces are equal - then steay-state flight occurs.

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23
Q

Describe the balance of forces in decelerative flight.

A

The thrust force acts in the same direction of the parasite drag and airspeed reduces.

24
Q

What two aerodynamical forces create the ground effect efficency?

A

Induced flow and vortex generation

25
Q

What relationship does induced flow have to ground effect efficency?

A

Induced flow velocity is reduced when closer to the ground, which increases the AOA, reduces the amount of induced drag, and allows a more vertical lift vector.

26
Q

What relationship does vortex generation have with ground effect efficency?

A

The downward and outward flow of air in ground effect has a restricting effect on vortex generation. Smaller vortexes result in the increased production of lift by the outboard end of the rotor blade.

27
Q

What is translating tendency?

How do we compensate for it?

A

The right lateral tail-rotor thrust exerted to compensate for the main rotor tourque results in the aircraft drifting slightly to the right.

SAS, flight control rigging,

28
Q

What are the regions of the airflow in forward flight?

A

Reverse Flow

Negative Stall

Negative Lift

Positive Lift

Positive Stall

29
Q

What causes the Reverse Flow lift of the rotor disc?

A

Wind created by forward airspeed being greater than rotational velocity at this point on the blade.

30
Q

What causes the Negative Stall portion of the rotor disc?

A

Rotational velocity exceeds forward flight velocity.

31
Q

What is dissymetry of lift?

How do we compensate for it?

A

It is caused by the different wind flow velocity across each half.

The advancing half of the rotor disc is accelerating faster than the retreating half, causing an upflap that reduces AOA.

The retreating half of the rotor disc loses lift and flaps down, increasing AOA due to decreasing induced flow velocity.

It is compensated for by blade flapping and cyclic feathering.

32
Q

What is transverse flow effect?

When does it occur?

What are the effects of transverse flow effect?

A

It is where airflow over the forward half of the rotor disc becomes more horizontal and more vertical over the second half.

It occurs between 10 to 20 knots and results in a right rolling motion of the aircraft.

33
Q

What is effective translational lift?

What are the indications of ETL?

How do we compensate for it?

A

It occurs between 16-24 knots, and is when the rotor completely outruns its old vortexes and begins to work in relatively undisturbed air. The flow of air becomes more horizontal, thus reducing induced flow and induced drag.

The nose pitches up and the aircraft rolls right.

Forward and lateral cyclic.

34
Q

What are the three blade regions during a vertical autorotation?

A

Driven, Driving, Stall

35
Q

Describe the Driven region of the rotor disc during a vertical autorotation.

A

It is the region nearest the blade tip. It take up roughly 30% of the rotor radius. It creates lift, which slows the rate of decent and drag, which slows rotation of the blade.

36
Q

Describe the Driving region of the rotor disc during a vertical autorotation.

A

The region extends from about 25% to 70% of the rotor disc. This is the region that turns the blades that produces force during autorotation.

37
Q

What is the Stall region of the rotor disc during a vertical autorotation?

A

It is the inboard 25%. It operates above the stall AOA and causes drag, which tends to slow the rotor disc.

38
Q

Where are the two points of equalibrium during a vertical autorotation?

A

Between the driven and driving regions; between the driving and stall region.

39
Q

What is your bucket speed?

How do you calculate it?

Which number is more important?

A

The envelope providing the best power margin for maneuvering flight.

It is calculated by using 50% of max torque avaiable on the appropriate cruise chart. Travel up that line until you intersect your gross weight twice.

The lower, because altitude loss during a turn might be unavoidable if below this airspeed in a turn.

40
Q

Describe Transient Torque during a left turn.

A
  1. ) Gyroscopic process = input being made over the tail, where downflap is at its greatest.
  2. ) Because of this, there is an increased AOA.
  3. ) The increased AOA also increases induced flow, which increases induced drag (tries to slow down the rotor system)
  4. ) The DECU recognizes this and responds with more power.
41
Q

Describe Transient Torque during a right turn.

A
  1. ) Gyroscopic procession = input taking effect over the front of the rotor.
  2. ) Because it is in the front of the rotor, the upflap is greatest, requiring less induced flow.
  3. ) This results in less induced drag.
  4. ) Because drag is reduced, the rotor tries to speed up the rotor, which the DECU recognises and stops by taking out power.
42
Q

What are the 5 factors that affect how much Transient Torque change occurs? (PAW-MD)

A
  1. ) The amount of power applied at the time of the maneuver
  2. ) Rate of movement
  3. ) Magniture of displacement
  4. ) Higher forward airspeed
  5. ) High aircraft weight
43
Q

What is mushing?

When will it normally occur?

What can aggrivate mushing?

How do you recover?

A

A temporary stall condition when rapid aft cyclic is applied at high forward airspeed.

During dive recoveries.

High GW and high DA.

Make forward cyclic movement.

44
Q

What are the 5 things that affect performance?

A

DA

Atmospheric Pressure

Altitude

Temperature

Humidity

45
Q

Describe Settling with Power.

What are the conditions for settling with power?

A

It is a condition in powered flight where the helicopter settles in its own downwash.

Rate of decent greater than 300 fpm, airspeed below ETL, and anywhere from 20 to 100% power available with insufficient power remaing to arrest the maneuver.

46
Q

What are the conditions are conducive to settling with power?

A

Steep approach

Downwind approach

Formation flight approach

Hovering near max hover ceiling

Masking/unmasking

Not maintaining constant altitude during an OGE hover

47
Q

What is required for Dynamic Rollover?

A

Pivot point, rolling motion, and exceeding the critical angle (static angle)

48
Q

How do we prevent dynamic rollover?

A

Inattention, Inexperience, Failure to take timely corrective action, Inappropriate control input, Loss of visual reference.

49
Q

What is retreating blade stall?

A

When the outboard tip of the retreating blade begins to stall at a high forward airspeed. The tip will no longer be able to acheive the AOA required to produce lift, causing a stall. As the condition presists, it will move inbound.

50
Q

What conditions produce Retreating Blade Stall?

A

High GW

High DA

High G maneuvers

Low rotor RPM

Turbulent air

51
Q

How do you recover from Retreating Blade Stall?

A

Reduce collective

Reduce airspeed

Reduce severity of the maneuver

Reduce altitude

Increase rotor RPM to normal limits

52
Q

What determines the emitted IR energy of an object?

A

Reflectance

Absorbance

Transmittance

Emissivity

53
Q

What is the Minimum Resolvable Temperature?

A

The lowest temperature difference that can be resolved, normally less than one degree,

54
Q

What are your considerations for optimizing FLIR?

A
  1. ) Device allowed to cool
  2. ) Scene rich in detail
  3. ) Desired polarity
  4. ) One control should be adjusted at a time (level/gain)
55
Q

What is IR Crossover?

What is subject to IR Crossover?

A

Where two objects are within the MRT of the sensor, and thus can not be differentiated between.

Soil, concrete, and water crossover twice daily.

56
Q

What is the Parallax Effect?

A

The conflict in imagrey seen between your unaided eye and your aided eye, mainly when sitting in the back seat. The back seat is 10 feet behind and roughly 3 feet above the TADS/PNVS turret.

Aviation Whatnot (4 decks)

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