Spin -Cont. - P-330

CHAPTER SIX

T-34C CONTACT

oscillations with no other significant change to the spin characteristics from lateral

stick inputs. With stick into the spin, the oscillations continued for about five turns.

Stick opposite the spin resulted in the pitch oscillations damping out within three

turns.

Spin Rate. The spin rate varies with direction of spin, power setting, configuration,

and center of gravity. Spins to the left average about 120 per second with right spins

being slightly faster at about 150 per second.

Rate of Descent. In a steady state spin, the rate of descent will be about 9000 to

12,000 feet per minute, depending on power setting. This is about 375 to 500 feet per

turn. At idle power the rates will be at the lower values. At these high rates of

descent, the altimeter may lag by as much as 1000 feet.

Cockpit Indications. Erect steady state spins typically indicate 80 to 100 KIAS, 30

units AOA, turn needle fully deflected in the direction of spin, and master caution and

low fuel annunciator lights may illuminate. The turn and slip indicator is mounted

approximately on the spin axis of the airplane at the lower center of the instrument

panel. The ball gives no useful information about the spin direction, as it remains

basically centered. In the event of disorientation or lack of visual cues, the only

reliable instrument that indicates spin direction is the turn needle.

Spin Recovery. The recovery from a spin requires a mechanical input of flight

controls to specific positions. To recover the T-34C from an erect spin apply full

rudder opposite the spin direction, stick forward of neutral, and neutral ailerons. The

control inputs should be brisk and the T-34C responds best to an almost simultaneous

application of opposite rudder and stick forward of neutral. The rate of rotation will

speed up slightly after anti-spin controls are applied, but recovery should occur within

one to two additional turns after recovery is initiated. The airplane will then be in a

steep nose-down dive and controls should be neutralized and the plane flown out of

the ensuing dive in a timely manner to avoid excessive airspeed, but also avoiding

secondary stall or excessive Gs. The NATOPS Manual warns that abrupt aft stick

movement near accelerated stall speeds is prohibited due to the possibility of

structural damage, therefore spin control inputs should be smoothly applied. Stick

Position. Although the rudder is the principal recovery control, the control which

requires the most critical positioning is the elevator. The stick must be positioned

"FORWARD OF NEUTRAL." Note that this is not "slightly" or "just" forward of

neutral. The importance of this longitudinal stick position was determined during

NAVAIRTESTCEN spin tests when it was found that an inadvertent aft stick position

of only inch behind neutral increased the recovery to as many as six turns. Because

of this it is much better to have the stick too far forward than too far aft, and we stress

the proper longitudinal stick position is "forward of neutral."

If Spin Does Not Recover. If a recovery from an erect spin does not occur within

two turns after applying recovery inputs, verify cockpit indications of AOA, airspeed

and turn needle for a steady-state spin. Verify full rudder applied opposite direction

of turn needle and stick forward of neutral (no aileron). If no indication of recovery

6-32 FLIGHT PROCEDURES