Aero Ii Ch. 10

Front 1

Define spin and autorotation.

Back 1

Spin
o Aggravated stall that results in autorotation.
• Autorotation
o Combination of roll and yaw that propagates itself and progressively gets
worse due to asymmetrically stalled wings

Front 2

Identify the factors that cause a spin.

Back 2

For an aircraft to spin, it must be stalled and some form of yaw must be
introduced.

Front 3

Identify the effects of weight, pitch attitude, and gyroscopic effect on spin entry.

Back 3

Weight
o Weight away from the center of gravity creates a large moment of inertia
for a spin to overcome.
• Pitch Attitude
o Will have direct impact on the speed the aircraft stalls.
o The higher the pitch attitude, the greater the vertical component of thrust,
and the lower the stall speed.
o Slower stall speeds make spin entry slower and will less oscillations.
o Lower pitch attitudes, the aircraft stalls at a higher airspeed and entries are
faster and more oscillatory.
• Gyroscopic effect
o T-34 in a right spin, the nose will tend to pitch down due to the clockwise
rotating propeller.

Front 4

Describe the angles of attack and forces on each wing that cause autorotation
during a spin.

Back 4

In a left rolling stall
o the left down-going wing has a higher AOA and is stalled more than the
right wing.

Front 5

State the characteristics and cockpit indications of normal and inverted spins.

Back 5

Erect (Normal) Spin
o Result from positive G stall entries.
o Altimeter will rapidly decrease, airspeed will be stable, AOA will be 30
units pegged, the turn needle will be pegged in direction of spin, the VSI
will be pegged, and the attitude gyro may be tumbling.
• Inverted Spin
o Results from negative G stall entries
o Altimeter will rapidly decrease, airspeed will be zero, AOA 2-3 units, turn
needle pegged in direction of spin, VSI pegged, attitude gyro may be
tumbling, and accelerometer will show 1 negative G.

Front 6

Identify the effects of control inputs on spin recovery.

Back 6

The rudder is the principle control for stopping autorotation.
• Opposite rudder (anti spin rudder) creates drag that can be divided in a horizontal
and vertical component. Opposite rudder maximizes both components.
• The horizontal component creates a force that opposes the yawing of the airplane
• The vertical component creates a force that pulls the tail up and pitches the nose down.

Front 7

State how the configuration of the empennage and placement of the horizontal
control surfaces can affect spin recovery.

Back 7

T-34 use a dorsal fin, strakes, and ventral fins to decrease the severity of
spin characteristics.
• Dorsal Fin – is attached to the front of the vertical stabilizer to increase its
surface area. This decreases the spin rate and aids in stopping autorotation.
• Ventral Fins – located beneath the empennage decrease the spin rate and aid in
maintaining a nose down attitude.
• Strakes – The T-34 has strakes located in front of the horizontal stabilizer. They
increase the surface area of the horizontal stabilizer in order to keep the nose
pitched down and prevent a flat spin.

Front 8

Describe the spin recovery procedures for the T-34C.

Back 8

1) Landing Gear and Flaps: Up
2)Verify spin indications by checking AOA, airspeed, and turn needle
3)Apply full rudder opposite the turn needle
4)Position stick forward of neutral position (ailerons neutral)
5) Neutralize controls as rotation stops
6) Recover from the ensuing unusual attitude

Front 9

Define progressive and aggravated spin.

Back 9

Progressive Spin
o If proper spin recovery procedures are not followed, you can reverse spin
direction
o You will get into a progressive spin if, upon recovery, you put in full
opposite rudder, but inadvertently maintain full aft stick.
• Aggravated Spin
o Results from pushing the stick forward while maintaining rudder in the
direction of spin.
o Characterized by a steep nose down pitch ad an increase in spin rate.