Stalling, Spinning & Spiral Dives Flashcards

1
Q

What is an aircraft stall?

A

The significant breakdown of streamline flow into turbulence over an aerofoil

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2
Q

When is an aircraft stalled?

A

When the critical angle of attack of the wings is exceeded

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3
Q

Why is stalling bad?

A

When an aircraft stalls, the lift production reduces and so no longer balances weight. Drag increases significantly

The aircraft will descend.

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4
Q

What is laminar airflow?

A

Smooth, streamline airflow over the wing

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5
Q

What is the transition point?

A

The point at which laminar airflow changes to turbulent airflow

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6
Q

What is the separation point?

A

Turbulent air separates from the upper surface of the aerofoil

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7
Q

What are the symptoms of a stall?

A
High nose attitude
Low airspeed
Stall stick postion
Stall warning
Buffet
Mushy controls
Nose drop
Wing drop
Inability to stop descent
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8
Q

What is the stall speed?

A

The speed below which an aeroplane will stall

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9
Q

Does an aircraft stall at a speed or an AoA?

A

An AoA

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10
Q

How does an increase in weight impact stall speed?

A

Increases stall speed

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11
Q

How does an increase in altitude impact stall speed?

A

No impact

Stall speed is an IAS which does not change with altitude

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12
Q

How does an increase in power impact the stall speed?

A

Lowers stall speed

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13
Q

How does an increase in bank angle impact the stall speed?

A

Increases stall speed

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14
Q

What impact does lowering flaps have on the stall speed?

A

Lowers stall speed

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15
Q

What impact does moving the CoG forward have on stall speed?

A

Increases stall speed

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16
Q

What impact can windshear have on stall speed?

A

Windshear can change the direction of the relative airflow causing the critical angle to be exceeded with no control input

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17
Q

What impact will frost and ice normally have on stall speed?

A

Normally, the critical angle remains the same and only the stall speed changes

The exception is hoar frost

18
Q

What is hoar frost?

A

Where an aerofoil is covered in frost and/or ice

19
Q

How does hoar frost impact stall speed?

A

Decreases the critical angle and increases the stall speed

20
Q

Why does a wing drop in a stall occur?

A

The wing that drops has stalled first

21
Q

Why should aileron input be avoided in a stall recovery?

A

May deepen the stall of the wing and the aircraft may enter a spin

22
Q

How does a rectangular straight wing tend to stall?

A
Root first then spread outward
Generally good handling
Good aileron control
Good stall symptoms
Nose down at the stall
23
Q

How does a swept back wing tend to stall?

A

Tips first then spread inwards
Poor handling
Can cause a wing drop
Can cause pitch up due to CoP moving forward, deepening the stall

24
Q

What are some methods to improve stall handing characteristics?

A

Washout
Stall strips
Vortex generators
Wing fences

25
Q

What is wing washout?

A

Wings have a lower angle of incidence at the tip than at the root. So the root will stall first

26
Q

What does wing washout do?

A

Better aileron control
Early buffeting of the tail
Reduced chance of wing drop

27
Q

What are stall strips?

A

Sharp edges strategically placed on the leading edge to cause certain areas to stall before others

28
Q

What are vortex generators?

A

Small surfaces place on the upper leading edge to delay a stall

29
Q

How do vortex generators work?

A

Create stable vortices on the upper surface of a wing

Delaying separation and so stall

30
Q

What are the benefits of vortex generators?

A

Increase stall AoA and reduce stall speed

Increase control effectiveness

31
Q

What are wing fences?

A

Vertical surfaces which run along the chord of the wing

32
Q

What do wing fences do?

A

Minimise span-wise flow

Generally improve handling characteristics

33
Q

When does a spin occur?

A

When one wing stalls more than the other wing

Usually when stalled uncoordinated

34
Q

What happens in a spin?

A

The more stalled wing drops and this causes the aircraft to roll and yaw towards it

This stalls the win further, causing an eventual stable rotation

35
Q

What is autorotation?

A

When the roll and yaw in a spin is stable

36
Q

Is the aircraft stalled in a spin?

A

Yes

37
Q

Is the aircraft stalled in a spiral dive?

A

No

38
Q

When does autorotation occur?

A

A spin

39
Q

What are the indicators of a spin?

A

Low and steady airspeed
Steady rate of descent
Low g-forces

40
Q

What are the indicators of a stall?

A

High and increasing airspeed
High increasing rate of descent
High g-forces

41
Q

What is the stall recovery?

A

Reduce AoA
Apply full power
Maintain directional control with the rudder (until un-stalled)

42
Q

What is the spin recovery?

A

Power to idle
Ailerons neutral
Rudder full opposite to the direction of rotation
Elevator forward