Page 738 - PPL-engelsk 2025
P. 738
Aircraft general knowledge
8.9.4.2 Engine cooling by gasoline
Modern aircraft have adopted the technique of gasoline injection.
Excess gasoline can also cool the engine. Gasoline and air are mixed immediately
before each cylinder, or the gasoline is injected directly into each cylinder.
Excess gasoline is added, what is called a rich mixture. That is, less than 15 parts
air to 1 part gasoline. The extra gasoline evaporates in the engine, and this
causes a temperature drop.
An injection system allows for very precise control of the mixture ratio – and thus
better economy.
There is no problem with carburetor ice with the fuel injected engine!
It can be done electronically and monitored electronically.
8.9.4.3 Engine cooling by air
The aircraft engines we fly with are primarily
cooled by air.
The cowling is equipped with air intakes at the
front.
Baffles guide the air around the cooling fins of
the cylinders and further downwards.
An instrument may be fitted to measure and control the
engine's operating temperature, which shows the cylinder
head temperature CHT (placed on the hottest cylinder).
8.9.4.4 Air supply and alternative air supply
Air supply is normally through an air filter and from there to the carburetor.
Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 738
