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Andrew,
I hope you have better luck than I with
the radiators mounted behind the engine. I tried this and I was
never able to get the necessary cooling. I had the ducting bring the air
around behind the radiator like you do. This caused the air to have
to make a 180 to enter the radiator, then another 180 to exit the cowl. I
was just never successful in convincing the air to do this loop the loop.
I saw a rear mounted radiator that I thought
might work where they had sealed in a deck on the top of the engine that only
allowed the air that entered the nostrils to exit thru the radiator and oil
cooler like you see on the Lycosaurus. I just didn’t have the wherewithal
to do that with the Mazda.
I finally copied Tracy’s radiator installation on the
RV-8/20B. (all my better ideas were copied from somebody!)
I think that if I were to do it all over
again, I might move the starter from the bottom of the PSRU plate, to the
co-pilot side of that plate, which would provide room to install the radiator
under the engine as far forward as I could get it, and mount the oil cooler on
the co-pilot side. This would allow the chin scoop to feed the
radiator, the right nostril to feed the oil cooler, and the left nostril to
feed the engine. This gives the air pretty much a straight shot thru the
cowl. (I am not certain who this is copied from, but rest assured it is
from someone!)
Right now I can climb full power to about
pattern altitude at Vy (100knots), then I need to reduce power and/or speed up
to bring the temps back in line. I cruise at about 180 water and 170
oil. I think that if I made the changes I mentioned, I could climb
unlimited and would need cowl flaps for cruise.
Bill
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
Sent: Tuesday, June 21, 2016 7:56
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: rebuild
took some photos yesterday of heat exchangers while motor is out for
new seals. Found a old lifting apparatus from the hospital that is
perfect for removing and rebuilding engine. Radiator and oil cooler are in the
only logical place under the cowl but getting clean air to them is problematic,
cowl is just to tight to place them anywhere else so not sure what I can do to
improve flow, testing with a leaf blower showed good distribution of air across
the exchangers, so maybe opening up duct entry for more air is a
possible solution.other solution seems to be to move them behind the spar
and use a belly scoop.Andrew
On Fri, Jun 17, 2016 at 8:24 PM, Jeff Whaley <flyrotary@lancaironline.net>
wrote:
Hello Andrew, first congrats on getting airborne …
if you’re blowing steam between the housings check them for warping or
rather ensure there is none.
Do you have any pictures of your setup? – One is
worth a thousand words.
28 sq” total air inlet seems a bit small to be
feeding both the radiator and oil cooler … my 2 cents worth …
Jeff
Well, been about
10 days since I steam cleaned the engine during the first flight, due to work
just managed to pull the engine apart, bit of fun for a novice, must say I was
a bit apprehensive but now am wishing I had built it from scratch initially.
for the life of me I cannot see anything obvious as being a problem so just
going to get some o'rings and reassemble as per the manual.
Now the whole
problem was caused by the idiot operating it, I was so preoccupied trying to
get oil cooling under control I had forgotten that I had the wrong coolant
inlet hose on, I had done this on purpose during construction as it enables
purging the air from the system without the multiple heat cycles saving time.
the needed reinforced hose was still on the shelf. so there goes, I admit it.
and to think Lynn
has made comment about this in his posts recently, I can only kick myself. Nuff
said.
A few observations
My plane flies
beautifully. I'm really happy with it, it feels safe.
The exit air
openings on the top front of the cowl work (Peter Garrison/Mellmoth style).
could quite easily see the low pressure area working above the cowl during the
steam clean. coolant on the windscreen is an annoyance but no worse than flying
in rain. Oil could be worse but a cessna with catastrophic oil leak puts it on
the windscreen too. I saw the very first puff out of the cowl and was able to
land within a couple of minutes with coolant remaining. steam exiting engine
between rotor housing & rear end plate in region of spark plugs. once the
engine cooled down refilled coolant, engine started & ran as normal just
slow pressure leak.
Oil cooler is 20b
Cosmo, but is just not working good enough, think it is because it shares
plenum with radiator and radiator possibly has less air flow restriction, don't
know. will try again when motor is going then attack the cooling system. May
even start from scratch if it tries to scare me again.
Currently plenum
opens just under the prop 28 sq" diffuses for 700mm/27.5" to 68
sq" turns about 80 deg up at the firewall base, is pinched to 59 sq"
in the turn into a wedge duct on the back of the radiators which sit side by
side. coolant radiator fin area is 450mm x 380mm x 60mm, oil 220mm x 290mm
about same thickness but denser fins. air the exits on top front of cowl &
3 exits on bottom.
I always presumed
my cooling problems caused by the exits as I can run the engine all day at
reasonable power on the ground with top cowl off. but obviously not at rpms
capable of collapsing bottom hose
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