Mixture and Engine Pitch..

[Skoshi Tiger]

Originally Posted by Blackdog_kt

Let's start simple with the mixture. In order to have a well-running engine you need a specific proportion between fuel and air. However, the higher you go, the less air there is to burn. That means we need to reduce the amount of fuel in the mixture to maintain that optimum proportion or the engine will choke due to too much fuel, hence the mixture controls.

Just to add, a carburetor meters fuel through the volume of air that passes through it, one cubic foot of air at sea level has the same volume of air as one cubic foot of air at 20,000 feet.

Unfortuanately the fuel/air ratio is based on mass.

One cubic foot of air at sea level has a higher mass than One cubic foot of air at 20,000 feet, therefore to get the correct fuel/air ratio you need more fuel per volume at sea level than you do higher up.

Cheers!