Ancillary Controls lesson
Carburetor Heat
Mixture Control
Carburetor Heat: Icing
ice can form in the induction system:
- Moist atmospheric condition.
- -5°C to +30°C .
- Caused by the absorption of heat from the air during vaporization of the fuel.
- Also caused by venturi effect.
Indication of icing:
- Loss of RPM with a fixed piched controller
- Loss of manifold pressure with a constant speed controler.
What to do:
- Immediately use: full carburetor heat .
Note:
- In general carburetor heat should not be used while taxiing because in the “on” position the intake air usually bypasses the carburetor.
- Avoid using carburetor heat during take-off, except during special procedures (very low temperature), since it may cause detonation and engine damage.
Carburetor Heat: system
Mixture Control
Mixture too rich:
- Lower power
- Uneven running of engine
- Engine too cool
- Fuel is wasted
- Possible spark plug fouling
- Range is reduced
Mixture too lean:
- Power will be lost
- Engine may run rough and vibrate
- Engine too hot
- Engine damage due to detonation
Review questions
- What effect does too rich a mixture have on the aircraft ?
- What effect does too lean a mixture have on the aircraft ?
- What is the first indication of icing to the pilot ?
- Why don’t we use carb heat during taxiing?
