Jerry Bass wrote:

Two years ago, I used Water-Weter, with no antifreeze, like the Bike

racers use. It did not lower the water cooling effect any more than

50/50

water and antifreeze.

Jerry Bass
540-932 3125
Cell 241-2675

Hi Jerry and Roto Heads,

I also tried Water Wetter with deionised water and it enable me to

almost

eliminate my step climb in hot wheather. In short it worked for me. My

red

light comes on at 110 C . With 50/50 Glycol. red light at anything over
500fpm hot day. WW try for 1000fpm.
My system for extending fuel range is to get high fast, then run  full
throttle leeeeen but keep her smooth.
Ian Beadle. Western Australia.

Do you have a 30 psi pressure cap Ian? 2 Kg/M^2
I think your boiling point will go up.

Paul Lamar

 Hi Paul

Ian Beadle wrote:

My pressure cap is 10psi (69 KiloPascals)  on the overflow tank and is the
needle valve type. It is supposed to hold 10 psi independant of outside
pressure. Does this mean if I flew to zero outside pressure I would still
have 24 psi I wonder? The system does not lose any coolant and things get
fairly warm around here.
On the graph it appears that I should be boiling at 5000ft at less than 100
degrees C. In fact I can go above 120C with no indication of boiling. By the
way I try to keep the temp. down as I do not have silicon O rings.

Happy flying Ian.

When you went into the graph did you add the ten psi cap pressure 
to the dotted ambient pressure line? When I added the ten psi to the
pressure at 5000 feet and 50% glycol I got just about 245 F or about
120C.
By god that chart works :)

I think it is 10 psi above whatever the outside ambient pressure is.
Same goes for the 30 psi pressure caps. Therefore the boiling
temperature
comes down with altitude. So too does the ambient temperature
fortunately.
So too does the need for cooling as the max HP also comes down.
On the down side of this the air is less dense (to cool) but the 
increased cruising speed may make up for this factor. I think
max angle climb at high altitude is one of the worst cases.

It would be interesting to build an absolute pressure cap somehow.
Do you have a sketch of that absolute 10 psi needle valve you have?
I would think one would need an ambient pressure sensor, a PIC and 
a servo of some sort. Could be wrong. First thing that popped into 
my head. A simple closed evacuated metal bellows with a spring 
inside of it could act on the needle valve directly. As the ambient
pressure went down the force on the needle would increase. 


Paul Lamar
 
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