Page 742 - PPL-engelsk 2025

Aircraft general knowledge

Here are the general instructions.

If the engine gets too hot, you can:

- open the cowl flaps (if equipped)

- make the mixture rich

- reduce pwr.

- increase the speed (at the expense of altitude unless you are flying slow flight)

8.9.5.2 Using Mixture Control

A certain ratio of air to fuel gives the highest engine performance.

This ratio is approximately 15 parts air to 1 part fuel.

See the diagram here.

At the highest

performance,

the most heat is

produced.

But some of this

is used to

evaporate the

fuel.

The engine temperature is indicated by the blue line as the temperature of the

cylinder head.

Note the cylinder head temperature at 8% lean and 10% rich mixture.

Note the fuel consumption at 8% lean and 20% rich mixture.

How do you think the manufacturer states the fuel consumption and range of

the aircraft?

You can run out of fuel if you don't read the numbers correctly!

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 742