Spinning

Question 1

What is spinning

Answer 1

Pitching/Rolling/Yawing around vertical axis without input

Question 2

Stages to a spin

Answer 2

Incipient
Fully developed spin
Recovery phase.

Question 3

Incipient Spin

Answer 3

Aircraft stalls and autorotates.
Initial roll and settle nose down

Recovery:
- Centralise the controls

Starts - When ac begins to autorotate
Ends - First full turn through 360 degrees

Question 4

Autorotation

Answer 4

After the stall but prior to the spin

Definition: Occurs after the stall but before the spin fully develops. Ac pitches/roll/yaws around a vertical axis without control inputs

Both wings are stalled but one is more deeply stalled than the other

Inside wing has less lift and more form drag
Ac roll and yaw towards the drag
Due to yawing cp behind CG nose will rise
One wing is stalled more than the other - both are stalled

Question 5

Fully developed spin

Answer 5

Stable flight conditions no control inputs needed to maintain
Steady yawing rolling pitching flight

Question 6

Recovery Phase from fully developed spin

Answer 6

Close power (remove torque forces from propeller)
Apply full opposite rudder in opposite direction
Push control column central forward

Question 7

Spiral Diver (Difference from spin)

Answer 7

Airspeed increasing/ G force increasing/Nose further below horizon
Forgetting to level wings before trying to pull out of a dive

Question 8

CG Position on Spinning

Answer 8

Forward CG - Steeper spin (easier to recover from)
Aft CG - Flatter spin (relative airflow is vertical)

Question 9

AC characters for a flat spin

Answer 9

Low aspect ratio wings
Inboard engines
Mass concentrated on longitudinal axis

Question 10

Pro Spin Controls

Answer 10

Forced autorotation from pilot

Full up elevator and full rudder at the stall

Question 11

Buffet (Aerodynamic Warning)

Answer 11

Turbulent wake from air flow over TE over elevators
Reliable indicator on approach to stall

Stall strips on LE to encourage earlier flow separation

Question 12

Aerodynamic symptoms at the stall

Answer 12

Intense buffet
Increase aerodynamic noise
Wing drop
Abrupt nose down pitch (Rapid forward CP)

Question 13

Flapper Switch (Artificial stall warning system)

Answer 13

Mounted on LE
Stagnation point moves down and aft
Once stagnation point behind flapper airflow pushes on it
Horn alarm in cockpit

Question 14

AOA Vane (Artificial Stall warning system)

Answer 14

Rotates around own axis and measure relative to ac longitudinal axis

Question 15

Fixed Probe (Artificial Stall Warning)

Answer 15

2 ports which detect angle
Pressure differences sensed at each port and fed back to determine AOA

Question 16

Rotating probe (artificial stall warning)

Answer 16

Servo motor drives probe around until 2 pressures equal and then calculates wings AOA

Question 17

“Pitch Eyebrow”

Answer 17

Max safe pitch up angle on PFD

Question 18

Advantage of Artificial warners

Answer 18

Independent of pitot systems so any blockage in pitot system does not impact warning systems

Question 19

Power on vs Power off stall

Answer 19

Propeller AC:
High pitch angle means thrust vector pointing downwards contributing to lift reducing the stall speed
Slipstream from propeller increases lift reducing stall speed

Jets:
Under wing engines thrust line below ac CG full power pitch up couple

Question 20

Recovery of stick pusher

Answer 20

Announce
Disengage autopilot
Apply nose down elevator
Nose down trim
Reduce thrust
Roll

Question 21

Autorotation cause of roll and yaw

Answer 21

Difference in values of CL and CD for each wing that causes roll and yaw

Question 22

Effect of CG position on spin

Answer 22

Further forward CG = steeper spin
Further aft CG = flatter spin (difficult to recover)

Question 23

Mass along lateral axis will….

Answer 23

Spin with large amount of roll
Less yaw and a steeper pitch attitude

(Less sweepback/full tanks/engines mounted outboard)

Question 24

Mass along longitudinal axis

Answer 24

Will spin flatter

(High aspect ratio/inboard engines)

Question 25

Spiral Dive Recovery

Answer 25

Close power level/air brakes/level wings and ease out of dive

Question 26

Incipient Spin Recovery Action

Answer 26

Retard the throttle to idle
Ailerons neutral
Apply full opposite rudder to rotation of spin (look at turn needle)
Apply forward elevator
Recover from dive

Question 27

Spiral Dive

Answer 27

High static directional stability but low lateral stability

Small sideslip directional stability restore but weak dihedral effect lags behind

Question 28

Possible cause for auto recovery of aeroplane after the stall

Answer 28

The angle of incidence of the wing is larger than the angle of incidence of the horizontal stabiliser (negative)