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Hi Andrew: Based on your photos and what we can’t see, I’d say you have only a couple options. 1) Open the duct entry and 2) if there is no internal plenum
divider you could add one to separate the radiator airflow from the oil cooler. I must say you have an unconventional or unique install compared to the norm … the Mellmoth story does show that it can be done.
I think if you abandon this setup for a belly-scoop, you’ll need to replace both cores with more suitable profiles: wide but not too tall.
Jeff
From: Andrew Martin [mailto:flyrotary@lancaironline.net]
Sent: Tuesday, June 21, 2016 8:56 PM
Subject: Re: [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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