Elevator Trim

CHAPTER THREE

T-34C CONTACT

straight-and-level flight and during other prolonged flight conditions without the pilot having to

hold pressure on the controls. This is accomplished by deflecting the tab in the direction

opposite to that in which the primary control surface must be held. The force of the airflow

striking the tab causes the main control surface to be deflected to a position that will correct the

unbalanced condition of the airplane.

The trim tab controls are located on the left console in each cockpit. To apply a trim force, the

trim wheel must be moved in the desired direction. The position in which the trim tab is set can

be referenced by glancing at the trim indicators located at the trim wheel. However, the trim is

adjusted to whatever is required to relieve the control pressures. For this reason, the trim tabs are

referred to as "labor-saving devices."

The general sequence for trimming the aircraft is rudder, elevator, and aileron.

Rudder Trim. Rudder trim is usually set first, because a correction for yaw will

precipitate the need to change the trim setting for pitch and roll. Additionally, most pilots have

difficulty maintaining balanced flight (keeping the ball in the center) with rudder pressure for an

extended period. Thus, if rudder were trimmed last, both nose and wing would have to be

retrimmed to some extent. Initial trim applications will generally be large adjustments, which

require additional "fine tuning."

Trimming the rudder is more difficult, since you are wearing heavy boots and it is harder to

"feel" pressure on the pedals. Never stiff-leg both rudder pedals by forcibly holding your feet

against them. This may happen when the pilot is tense or excited. Try to rest your feet lightly on

the pedals when checking the BALANCE BALL for coordinated flight. For example, if the ball

is out to the right, the nose is actually out to the left and you are in a skid. Smoothly apply right

rudder pressure to regain balanced flight. Then smoothly apply right rudder trim until you

relieve the rudder pressure you are holding. If you have trimmed properly, the ball should stay

in the center and you should be in coordinated flight. Eventually you will be able to "feel" if you

are flying straight. An easy way to remember which way to trim the rudder is to "STEP ON

THE BALL."

Elevator Trim. To trim nose attitude, first move the stick to position the nose for the

attitude that you desire in relationship to the horizon. Then relieve the pressure you must

maintain on the stick by moving the elevator trim. If you must hold forward pressure on the

stick, slowly roll the elevator trim wheel forward (it is very sensitive) until the pressure is

relieved and the nose remains at the attitude which you desire. If you must hold back on the

stick to hold the desired attitude, slowly roll back the elevator trim wheel until you relieve the

pressure you must maintain on the stick. Always use a light grip on the stick so as to "feel" the

pressure. "Fingertip control" is the key to smooth flying. The T-34C is virtually impossible to

fly with a tight grip on the stick unless proper and constant trim is utilized.

Aileron Trim. Always make sure the rudder and elevator are trimmed properly before you

attempt to trim with the aileron trim tab. Aileron trim is only necessary if, after the rudder is

trimmed, the aircraft tends to roll to one side. If this is the case, level the wings with the stick,

and relieve the side pressure you must apply to the stick to maintain wings level by rolling the

3-6

USE AND EFFECT OF CONTROLS