Vince Orton wrote:

I have lurked for a while now, reading with interest the varied
solutions for increasing cooling capacity for liquid cooled

aircraft

engines.

The main problem is that liquid cooling is more difficult (less
efficient) than air cooling - mostly due to lower delta-T

(temperature

difference).

Here are some ideas that have been discussed:
- Proper ducting
- Cowl flaps
- Exhaust airflow augmentation
- Liquid spray on radiators to temporarily increase cooling
- Alternate coolants for greater delta-T

Some ideas that have been shot down include:
- Electric fans
- Radiators behind engines (in tractors)

Some ideas that I am surprised HAVEN'T been discussed:
- Engine driven fan
- Turbocharger fan/air pump

<Snip>
Another idea is to use only the amount of antifreeze necessary to keep the
coolant from freezing solid and add corrosion inhibitors as needed.
Straight water has a higher heat coefficient than an antifreeze/water mix.
It doesn't take that much antifreeze to keep the coolant from freezing
solid.  What happens is that the coolant turns to slush and the engine can't
pump it through the system.  If you keep the plane in a heated hanger or you
pre-heat it before starting the engine then there isn't a problem.  Once the
engine is running it will elevate the temperatrure where the coolant will
not return to the slush state. The other option is to run different
antifreeze/water mixes for the different seasons of the year.  Also,
recognize that the antifreeze also elevates the boiling point of the mix so
there is a tradeoff.

Del Johnson

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