I need some ideas on cooling a pusher type engine. Had one and if it idled any length of time it would overheat. I thought of a bigger head like a heli head but are they available for most engines or are they different. Just don't know but I am sure someone out there has the answer

Air flow is not a big part of the cooling of our engines. The amount of fuel (i.e. how rich you run the engine) plays a very much bigger part. In most instances of overheating, I've found the solution to be run less oil and slightly richer.

Without the specifics of your set up it hard to offer better advice.

Bill

Get it all tuned up with a tractor prop

Change to the pusher prop and immediatly fly

In most tractor type of setup airflow is not a big issue...
Pushers however have some real issues as far as air cooling goes.
One thing that will help as mentioned is the mixture and oil content.
Not knowing what your setup or engine is it would be hard to offer any real solid advice.
I would recommend that you get a copy of Andy Lennon's book "Basics of RC Model Aircraft Design", it has an entire chapter on engine cooling/cowl design, that has quite a bit of focus regarding pusher type of setups.
Perhaps you could elaborate on what type of airframe, engine setup you are using. That would give me a better idea of how to advise you on your setup.

Edit to add:
The suggestion about using a tractor prop for tuning and switching to a pusher is an excellent one, if your only issue is getting it set up...

I have experienced the problem with a number of different engines on a Bob Cat. The lack of pusher prop sizes makes the problem bigger than it should be. Running a smaller pusher prop than tractor seems to help some. Using a larger engine than would normally be necessary seems to help some. Going to the end of the runway and crank and go seems to help, i.e. no taxi time and no run up.

However the engine in pusher configuration often simply runs different in the air and I have not found a solution.

Bill

Hello all, I've got a collection of 3 magazines plus two "copied" articles on pusher jet model designs. These would be for sale if anyone is interested. They would take .25 on up to .60 sized (.75) engines for F-18s, T-33 Shooting Star, A-10 and a Canadair CT-114 Tutor trainer. I would post the ad in the "For Sale" section if anyone were interested.
Thanks,
Garyss