Engine Overheating

Ideas Please....

Thanks for all the replies in advance!

You and I are using basicly the same set up on your plane and my SV-22. I have the PA-61 but have never had a hot run that I can tell. Maybe we should compare the two and see if there is much of a difference?

Aye carumba! Why does everybody want to run 5% fuel, particularly in the hot humid weather? Going to 10%, or even better, 15, will let you run it a lot richer and keep it much cooler.

However, if you are *melting* the front seal, I would guess you might have the pipe too short, to the point you are reverse-pumping the engine.

Brdtt

Did you have the same overheating problem with the PA?

Yup, and Nope.

Guess I will lengthen the pipe somewhat and run some of the 10% fuel I have. When I see Randy at the Nats I hope he has some Aero-1 with him. I'll also add 2-3% synthetic oil to the fuel. I guess the PA's and RO's like things a little different. I could add some castor instead of synthetic I guess.

Thanks,

How's the air flow?

Airflow was plenty good with the PA. air flow might not be quite as good with the RO since it has a somewhat bigger case but a shorter cylinder.

My pipe length is set for 10,000 RPM at launch which comes out to around 17&5/8-3/4 inches. I can lengthen the pipe to 17&3/4 without any ill effects I believe. In fact, come to think of it, Rich and I are using the same prop and his is 17&3/4 I believe.

The prop is an Eather 121/2" regular blade cut down from 13"

Well, then it beats the heck out of me. For reference, I am running 17 3/8" with a launch RPM of 10000-10100, #5 spigot venturi, Eather 12.5-3.9 flat-back "green" and Powermaster R/C fuel.

Does the Infinity use a case cooling vent like Ted uses on the TP?
My plane doesn't have a case cooling vent and that could indeed be contributing to the heating problem. Unfortunately, I don't have time to make any cooling vents before the Nats and practice too.

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I actually have 50% more cooling vents. But there's no way that's making any difference - the case on my engine is actually cooler than ambient while it's running.

You have the front end, where the engine head sits, then a rear hole, then the pipe tunnel.

Try making the 2nd hole ( which is located above the tank ) slightyl larger..

It might not be fuel related.

Someone once told me the volume of air through that 2nd hole should be atleast double what the volume of ait throught the front of the cowl should be.
Not sure what truth there is to that, however as I said, a I did have that problem a few years ago my 2nd Vent opening was only 2" long

It's all important but it's so easy to fight the sophisticated when the simple things are the problem!