Page 759 - PPL-engelsk 2025

Aircraft general knowledge

You can see an illustration here.

In the design, there are 2 forces that force the blade

angle towards low pitch/low blade angle:

- centrifugal twisting forces

- oil pressure from the engine

The fine position is associated with many revolutions, and it is used for takeoff

and climbing.

If a coarse pitch/high blade angle is required, oil pressure from the governor (the

control mechanism in the system) is directed to the propeller, and then the

propeller is pushed into coarse pitch.

The governor ensures that the selected revolutions are maintained. If RPM tends

to increase, the blade angle increases, and the RPM is held constant.

The opposite is true when RPM tends to decrease. Here, RPM is held constant

by decreasing the blade angle.

The throttle lever (the gray one) determines how high manifold pressure should

be. The higher the pressure, the more power.

The blue lever controls the RPM. If you want fewer revolutions, pull the lever

back, and the governor sends more pressure to the propeller, so that it goes into

coarse pitch.

The red lever is

the mixture.

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 759