Buly,
Congratulations on getting your bird functioning again. Seeing your
data
really makes be happy to know you have adequate cooling as well as
good fuel
burn.
Great going.
Doug Fir
Thanks Doug. I have to improve my ground cooling now. It is because
of the pusher design, not the cooling system. I land with 170F WT. By
the time I taxi downwind to the hangar,temps are 210F. Even this
morning at 6AM while walking the dogs, I was thinking how to improve
the ground cooling?
It's a sickness I tell ya! :)
Buly
If this is the current configurations you need another of these
large round tubes on the left side that are cut off straight
just in front of the prop. Then add 45 degree root cuffs to the IVO
prop to suck the air through the rads. That is what I would do.
Paul Lamar ...No rotor no motor.
Buly,
Congratulations on the installation. It looks really good! Since you
are obviously very close to an adequate configuration, I would suggest
tweaking what you have, rather than adding another system. First, I
would make a little pitot tube and affix it to the entrance of the
ejector so you can get a relative measure of the velocity of the air
entering the ejector. This way you can try things quickly and determine
whether the results are good or bad. No need to fly the plane, since
the issue is with cooling on the ground at engine idle. By the way,
glass eye droppers make great little "laboratory" pitot tubes. Or if
you have an RC car hobby shop nearby, get a piece of brass tubing and
some silicone fuel line to connect it to a manometer. The pressure
differentials here will be very small. So, to see the relative
differences in pressure you will need to make a water manometer with the
low pressure side slanted at maybe a 70 to 80 degree angle. Clear vinyl
tubing works great for this.
Now, I would use cardboard and duct tape to try some changes to the
ejector tube. The angled end probably degrades the ejector
performance, try squaring that off. From the photos that Paul attached,
it is not clear how far into the ejector tube the engine exhaust pipes
are located. Try adding an inch or two to the ejector tube length at
the rear. The exhaust gasses need to be in the ejector tube for a
distance of one or two ejector tube diameters to get the best effect.
If these ideas don't give more apparent flow, then I would go by a
gutter shop and get a few feet of unformed aluminum and pop rivet
together some trial ejector tubes of different diameters. If I were
making a new trial ejector tube my first try would be this one; I
would keep the same entrance area, make it as long as possible, make it
oval similar to the exhaust pipe, and give it a taper of about 7% from
front to rear.
Also make sure the ejector tube is sealed to the cowl.
It is great to see a rotary installation so well done. I know it is
probably not feasible for you to have the plane at Sun N Fun. Could we
make a poster board and show off photos of your installation at the
rotary tent?
Aubrey Thompson
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