Why two rads? Why not just one on the cool side.... spark plug side
of the engine?

Paul Lamar

Paul, several reasons for two rads. First; I beleve I can get a better pressure
differetial across two smaller rads. Second; I would like to try to reduce
cooling drag by running the smallest outlets I can. Third; I can get the needed cu inches to fit easily within a conventional
cowl with the oil radiator in front lower,
(chin) position. Lastly; I would like to run a blow through heat shield around the exhaust to keep the temps down. Oh, and
really lastly; I can get the smaller radiators cheaply from my friends in the motorcycle business :-) Bill Jepson

Why do you think you can get a better pressure differential across two rads?
You can get small outlets by closing down the venetian blind cowl flaps.
Is this for a three rotor? If so motor cycle rads are not going to hack it.
You are looking at a 750 to 800 cubic inches in rads to cool a three rotor.
Paul Lamar

Paul, I may be using an erroneous figure to start with. I had recalled 300 cu inches plus 
the oil cooler for the two rotor. I then went 1/3 larger for the three rotor. I was 
incorrect on pressure differential of course, I should have said I believe TOTAL 
airflow with proper sized inlets would be higher. If 800 cu inches is needed a rethink 
will be needed. On the motorcycle radiators though I believe they will be just fine. 
There are many excellent bike rads around 200 cu inches. These are all aluminum 
furnace brazed units... real high quality.
The units I've seen are much better than the Griffin and other custom rads, I've 
purchased for race cars etc. Bill Jepson

I think you mean 1.5 larger or 150%.. 300 to 350 cubic inches per rotor.  
Nothing like under estimating your cooling requirements. Usually that results
in a painful total redesign and rebuild of the entire firewall forward package.
Chuck Dunlap is going through all that with his 500 cubic inch rad. A three rotor 
RV10 fully loaded on climb out is going to need a bunch of cooling
and cowl flaps for sure.

Not to say we could not get away with less but so far nobody has
done it yet except Perry and his ducted fan is a special case.

Best to over design until we get a much better handle on the optimum
configuration.

BTW Speaking of three rotor cooling. Tom Parkes, what do you think about the IVO
prop root cuff idea? You would be doing us all a big favor if you can figure out
a way of making that IVO prop work both for low speed cooling and top speed.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.