The power controls are the power control lever, condition lever, and emergency power lever.
These controls are located on a quadrant on the left side in each cockpit. They permit the pilot to
adjust the power output of the engine within its operating limitations.
Power Control Lever. The PCL controls the power output of the engine. This power,
transmitted through the propeller, produces thrust. As discussed in the previous chapter, this
thrust will propel the aircraft through the air, developing lift. When sufficient power is
combined with the appropriate angle of attack, the desired performance is obtained.
Moving the PCL forward increases power; moving it aft decreases power. If a constant airspeed
is maintained with adjustments in the attitude relative to the horizon, a variation in power will
control the gain or loss of altitude. This concept of control establishes a basic fundamental of the
mechanics of any powered flight.
The PCL should be operated firmly but smoothly. You will learn to set the desired power with
your peripheral vision and then go back and fine-tune the power as required for a particular
maneuver. Occasionally check to see that the desired power setting is still in fact set. Some
T-34C PCLs have a tendency to slip if the PCL friction is not sufficient.
Condition Lever. The power generated by the engine is converted to a usable force
(thrust) by the propeller. The propeller on the T-34C is a constant-speed, full feathering,
reversible pitch propeller. The condition lever controls fuel on and off, feather, and propeller
RPM, and is mechanically interconnected between cockpits. Moving the condition lever aft
towards a spring detent will reduce propeller RPM to minimum governed RPM. Further
movement aft past the detent to a positive stop will cause the prop to feather. This mechanical
stop can be released by the pilot in either cockpit by pushing a spring-loaded lever (stop lever).
When the stop lever is simultaneously pushed forward while pulling the condition lever aft, fuel
cutoff position may be selected to secure the engine. The stop will automatically reset when the
condition lever is moved forward out of the fuel cutoff position. The condition lever travel
range/positions are placarded on the quadrant and will be full forward to all normal operations.
Emergency Power Lever. In the event the pneumatic function of the fuel control unit
becomes inoperable, the manual fuel control system will provide the capability to restore power
with the Emergency Power Lever (EPL). When engaged, the EPL will provide a direct
mechanical linkage to the bellows and fuel-metering pin in the Fuel Control Unit (FCU),
effectively bypassing the pneumatic function while scheduling fuel to the engine. Basic
principles of operation are as follows:
Operation of the EPL requires lifting it up to move it forward and out of the
disconnect detent. Moving it back into the disconnect position requires pulling aft
and pushing down on the lever.
The EPL does not have the same range of travel that the PCL possesses. In other
words, forward movement of the EPL will achieve MAX ALLOWABLE power
sooner than a corresponding application of the PCL.
USE AND EFFECT OF CONTROLS