Hi Bud=2C
Thanks for your recommendations. I am only concerned because I don't recall
a coolant problem from previous years.
I did make anumber of changes to the way the air flows over the engine (Iha
ve a trigear 912S)=2C but they should all
help with the cooling and reduction of drag:
1) I cut back the aluminum duct tail end to the radiator and this is the ma
in air outlet to the bottom of the fuselage.
2) I sealed the gills.
3) I taped over the main stbd Naca duct.
4) I closed the outboard 60% of the two round inlets. I don't see the point
of cooling the exhaust pipes.
5) I closed the gap between the round baffle inlet and the baffle.
6) I reduced the height of the main inlet by about 30mm=2C streamlined the
interior of the duct=2C and made sure that
there are no more gaps either at the front or around the radiators.
7) The radiators are mounted just as you described.
8) The hoses all have a smooth run=2C and the two main ones to the radiato
r are silicone and preshaped.
In essence=2C I have reduced the cowl openings by 50% and doubled the exit
openings.
The performance improvement in the cruise is considerable. The temperature
under the top cowling is around
15 degrees C above oat.
I see your note about coolant mixture=2C and that concurs with a note in
the Rotax handbook. I think I will try that
and maybe change the pressure cap to 1.2 bar.
Karl<html><div></div>
From: budyerly@msn.comTo: europa-list@matronics.comSubject: Re: Europa-List
: Coolant Temps.Date: Wed=2C 2 Jul 2008 09:53:38 -0400
Karl=2C
Sounds to me like the duct sealing may have been compromised.
Another culprit can be the hose running from the top expansion tank to the
radiator. Sometimes that bend gets pinched a little.
I don't know what engine you have=2C but my experience here in Florida with
the XS cowl and Rotax engines follows:
1. Lower the oil cooler as far down as you can get it. Typically 1.5 inch
es is easily attained. That lowers oil temps nearly 15 degrees.
2. Make sure the cowl seal rubber is doing its job to include around the t
op front of the duct. Any high pressure air getting from the lower duct in
to the cowl cuts cooling. The engine is partially air cooled also.
3. Seal the gaps on the side and below the oil cooler. The duct works bes
t when entering air stacks up and slows down in front of the coolers so as
to get efficient heat transfer. I bend a piece of stainless which I attach
to the oil cooler bottom and bend it to make a nice tight seal underneath
also. When taxiing=2C that really makes a difference. I also continue the
seal back to the cowl exit.
Other techniques:
4. For info only=2C I run 70/30 Dexcool which doesn't boil until 276F vs.
265F for 50/50.
5. Taxi with coarse pitch to get more air in the duct.
If you have a mono=2C I do a number of other mods too numerous to email abo
ut.
Bud
Custom Flight Creations
----- Original Message -----
From: Karl Heindl
Sent: Tuesday=2C July 01=2C 2008 5:06 PM
Subject: Europa-List: Coolant Temps.
After changing all coolant hoses and coolant 50/50 I am now getting much h
igher coolant temperatures while taxiing and climbing=2C typically 25 C abo
ve the oil temperature. In the cruise the temperatures are all within 2 deg
rees of each other. I don't think I had this problem before. The radiator s
its in front of the oil cooler. What could be the problem ? The pressure ca
p is .9 bar.Any suggestions ?Karl <html><div></div>
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