>    Back to the manometer measurements, I got between 2.75" and 4"

pressure

in
 > various locations in front of the radiator. That is why I put that ugly
 > "tongue" on the bottom of the inlet, to try to even out the pressure. I
have
 > not measured all of the locations yet, but so far all have been 3". All
 > these measurements are the distance the water rises in the tubes

compared

to
 > static. Of course the water in the other tube lowers that same amount.

One

 > problem with keeping this calibrated is the water evaporates over the
course
 > of a few days and I have to keep moving my scale! Maybe I could change to
 > salad oil or something that does not evaporate but then all my
measurements
 > would be different due the different mass of oil Vs water.

Chuck, Paul

Measurements are good, helps make sense of things.

Instead of a manometer, one of the local builders here uses an airspeed
indicator, where he can connect the static to different probes also.  Easier
to read in the air than a manometer, and the water doesn't evaporate.  He has
been having cooling problems on an E-racer with a supercharged IO-540 in it.
was pulling his hair out with many cowling changes until he started making
the measurements. Found that the problem was that he was NOT getting adequate
air flow OUT of the low pressure side of the engine.  Made exit ramps (like
fixed cowl flaps) and still had too much back-pressure.  Finally has changed
to an exhaust augmentation system which pulls the pressure down.

Changes without measurements are shooting in the dark.

Bill Schertz
KIS Cruiser #4045

I could not not agree more Bill. Chucks highest priority is to
get the pressure down on the back sides of those rads in the cowl.

Another neat real low pressure meter is called a Magnahelix. They are 
widely used in the air conditioning industry but they, like altimeters,
are expensive.

The advantage of the water manometer is its cheap to make and many
pressure measurements can be made simultaneously. I used a Polaroid
in the old days to record the readings but a digital camera would
be perfect.

Paul Lamar
 
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org