T-34C OUT-OF-CONTROL FLIGHT
The T-34C has proven its capability to enter and recover easily from both post-stall gyrations and
spins. The NATOPS Flight Manual is the only source of officially recognized Out-of-Control and
Spin Recovery Procedures. Therefore, this FTI is designed to amplify and supplement the
101. THE ERECT SPIN
The motion of an airplane in a spin can involve many complex aerodynamic and inertial forces
and moments. However, there are certain fundamental relationships regarding spins with which
all aviators should be familiar. Two primary factors must be present for an airplane to spin:
Yaw (rotation about the vertical axis).
In the case of spins, we are concerned with the aerodynamic characteristics, which take place at
an AOA above a stall.
This discussion concerns the spin characteristics of aircraft with moderate to high aspect ratio
wings, moderate wing loading and with little or no sweepback (e.g., the T-34C).
In most airplanes, particularly light trainers, the rudder is the principal control for recovery.
Therefore, the configuration of the vertical stabilizer and rudder, as well as the placement of the
horizontal control surfaces, has a very important effect on spin recovery. Figure 1-2 illustrates
the T-34C rudder and horizontal stabilizer in various airflow conditions.
(Airflow Partially Blocked)
(No Airflow Blockage)
(Complete Airflow Blockage)
Figure 1-2 Rudder and Horizontal Stabilizer
In Figure 1-2, the swept vertical fin is very nearly blanked out by the horizontal stabilizer and
there is little, if any, effective rudder to stop rotation. For this reason, if you should enter an
inverted spin in an aircraft with a conventional cruciform tail (Figure 1-3), you will probably
1-2 INTRODUCTIONS AND SPINS