Figure 1-2 Rudder and Horizontal Stabilizer

T-34C OUT-OF-CONTROL FLIGHT

CHAPTER ONE

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

NATOPS Manual.

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:

Stalled AOA.

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