Engineer Ted's How to Make Your Engine Last (while running)

[21541803]

Newby at this, so tell me your truth
Enriching the mixture cools your engine they say. Due to "the evaporation of the excess fuel".
But, I can also cool the engine by reducing the AOA or by reducing the power setting. Less power, less pressure and less heat.

So can it be that the "evaporation concept" is an old school explanation (politically correct) as
enriching the mixture from the 14.7:1 to say 10:1 (will the engine run this rich?),
leads to poorer combustion which causes less power, leading to cooler temperatures.
Bottom line. What cools the engine? Evaporation or poor combustion?

 

[wetzelaviation]

Newby at this, so tell me your truth
Enriching the mixture cools your engine they say. Due to "the evaporation of the excess fuel".
But, I can also cool the engine by reducing the AOA or by reducing the power setting. Less power, less pressure and less heat.

So can it be that the "evaporation concept" is an old school explanation (politically correct) as
enriching the mixture from the 14.7:1 to say 10:1 (will the engine run this rich?),
leads to poorer combustion which causes less power, leading to cooler temperatures.
Bottom line. What cools the engine? Evaporation or poor combustion?

My aircraft doesn’t have a mixture so that doesn’t work on all aircraft (mixture) but lowering the nose and getting more wind definitely works every time. If temps get on the high side in some aircraft a shallower climb will put more air through the engine and cool it. So definitely can cool an engine by lowering the AOA and that’s what the manual tells me to do with mine.

 

[RyanB]

Newby at this, so tell me your truth
Enriching the mixture cools your engine they say. Due to "the evaporation of the excess fuel".
But, I can also cool the engine by reducing the AOA or by reducing the power setting. Less power, less pressure and less heat.

So can it be that the "evaporation concept" is an old school explanation (politically correct) as
enriching the mixture from the 14.7:1 to say 10:1 (will the engine run this rich?),
leads to poorer combustion which causes less power, leading to cooler temperatures.
Bottom line. What cools the engine? Evaporation or poor combustion?

They’re air cooled engines, so the primary mechanism by which heat is controlled is air flowing into the cowling. Vaporizing fuel requires energy, which comes in the form of heat, so when the fuel is atomized the temperature goes down. More fuel, more temperature change etc.