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I'm
trying to restrain myself from chopping up the cowl to install the
louvers. I can't see how they would help much, especially on the bottom
of cowl. Maybe on the top? Somebody STOP me!
Perhaps
it would be good to measure static pressure above and below the cowl before you
make any big ‘chops’ anywhere. Put some porous foam over the
end of your manometer tube with tube perpendicular to the flow. Problem
with louvers on top of the cowl is that any oil or coolant leaks may end up on
your windshield.
Measuring
pressure on the front face of the rad and comparing to pitot pressure may be
worthwhile. Your cowl off test may be such a radical departure from cowl-on
conditions that it could lead to false conclusions
FWIW,
Al
Tracy
On Sun, Sep 20, 2009 at 3:09 PM, Bill Bradburry <bbradburry@bellsouth.net>
wrote:
No air pressure under the cowl?? What is the
pressure drop across the radiator? What is the zero pressure referenced
to? If it is the cockpit, you may have pressure in the cockpit causing
the difference to be zero. It the pressure under the cowl is truly zero,
there will be little or no velocity of the flow out of the cowl so VGs will not
help. Al? said he had his cowl pressure at 5 inches to help speed
the air back up as it goes out.
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Tracy Crook
Sent: Sunday, September
20, 2009 9:03 AM
To: Rotary motors in aircraft
Subject:
[FlyRotary] Re: Another mixed day / Cooling experiments
"It IS seeping from the filter seal
and NOT the two hose connections...no doubt on this. "
Just from observing many rotary installation 'de-bugings' over the years
(including my own) I noticed that difficult to solve problems are almost always
caused by false assumptions.
It is possible to get several bad filters or two bad filter mounts but the
mathematical odds are staggeringly small. You haven't offered your
test proofs as to why you know they are bad and leaking but if I were betting,
I'd put my money on something else. The assumptions about the wiring
might need examination as well.
This reminds me of an oil leak the Ed Anderson had. The oil was showing
up on the back side of one of his rads. There was an oil line running
very close (< 1" as I recall) to the rad so the assumption was made
that the oil line was leaking. Long story short, the oil leak was actually
coming from something at the opposite end of the engine. What exactly was
it Ed? It defied all logic in that it was not even close to where it
showed up and the oil was traveling against the assumed airflow under the
cowl.
Speaking of assumed airflow, my cooling experiments are blowing away all my own
assumptions. I kluged up the cowl flap I mentioned and fixed it in the
open position. The trailing edge of outlet is about 1 1/2 "
below where it was. The temperatures were down a little but not
near what I wanted. Only a little better than the big giant opening I
tried. At this point I was ready to conclude that the underside of the
airplane was bad place to put a cooling outlet. Keep in mind that my
working assumption is that the pressure under the cowl is too high to allow
good airflow through radiator and oil cooler. I had installed a pressure
probe under the cowl but forgot to look at the reading. Figuring I
might as well know how big a problem I had, I made another flight to check the
under cowl pressure. Duhh, almost nothing! Checked the probe
to make sure it was not blocked, pinched, etc, and everything looked
OK. I need to check pressure in a few other spots to be sure about
this. There is something odd going on with airflow under the cowl but I'm
back ti head scratching mode again.
One builder on the RV list said he got a big improvement in cooling by
installing VGs on the trailing edge of the cooling outlet. This is so
non-intuitive that I can't imagine why it would work but its so easy to try I might
have to do it while scratching my head.
Tracy
.
On Sun, Sep 20, 2009 at 1:37 AM, Chris Barber <cbarber@bellairepolice.com>
wrote:
Made it out to the
hangar for most the day and decided to take the advice here and modify my start
up routine based on what was suggested here and in the manual. So, I
cranked the mixture full rich with no priming and it started up in a few
blades. Ran for a while, shut down and started back up with mixture in
about the 2:00 oclock position....and it started fine. Kewl.
The first bad news is that I replaced my romote oil
filter mount and installed a new filter. As I have mentioned here I have
had it leaking at the rubber filter seal. The old one looked ok, but
since replacing the filters no less than three times and knowing that the
eye cannot see all inperfections, I replaced the mount AND filter (K&N 2004
filter). But, NO JOY. It is still leaking where the filter mounts.
It IS seeping from the filter seal and NOT the two hose connections...no doubt
on this. I know the rotary's oil pressure is higher than other engines
but I would not think it would be so much that it is overwhelming this standard
mount and seal. This is just a standard screw on remote oil mount made
out of AL...Made in the USA.
Looks like many others I have seen. Y'all have any ideas.
Second good thing is a guy from a few hangars down
turns out to be a welder by trade. He came down as I was working on the
new stainless turbo exhaust manifold the other day after offering to help me
modify my manifold.. As was mentioned here before, the old cast iron
manifold I had wold work if mounted upside down. It puts the turbo lower
(the oil return being about 2 inches higher than the oil inlet return in the
pan) to the rear of the engine and it clears my aileron control link. I
will have to make a very small modification to the lower cowl to give me proper
clearance EXCEPT the wastegate interfeared with the Mistral intake fuel rail.
So, I ordered a stainless copy of the cast iron one I had, based on John Slades
suggestion. My welder friend said it would not be too big a job to turn
the wastgate extension around which should allow it to miss the fuel rail
completly. We looked at the options and he took the manifold with him
saying he would cut off the old wastgate extention and come back to fit the new
part on in a few days. Kewl.
The second bad news is that I was doing some continued
tuning. I even transferred A to B as B was a bit rough from the factory
and it worked fine. HOWEVER, later in the day, after feeling pretty good
about the lasted progress (excepting the continued leak) the engine stopped.
Huh? It will not restart. I checke the first fuel filter and it is
clear. I decided to start at the beginning and just run the EC2's
diagnostice test. Damn, no chattering of the injectors (even though I was
able to hear an individual click when I primed it). Put on a test
plug and wire and got no spark. All the other electrics are working fine.
I pulled my extra EC2 out and installed it and I got
injector clattering away and spark on three of the inectors. The
secondary on Rotor one did not seem to fire. Hmmmmm? I put on an
extra injector that I had and tried again, and it didn't fire...then fired for
a few seconds and then stopped. Looks like I have some more wire issues.
Damn, I though I had really gotten past most of those.
I am really confused about the EC2 seeming to just
shut down. The other electrical componants are all working, but the EC2
componants are not. Strange since I thought each items (injectors and
coils) had there own power source thus should not shut down as a
"team" like this. Yes, it is the same on A and B.
Currently I am very discouraged so I stopped for the night and decided to crawl
into bed with a hot blond and sulk (she was actually gracious enough to hang
out in the hangar with me for a few hours...whata gal)....well, she helps me
from sulking too much.....this dating in my 40's ain't all that bad
<g>
I anxiously wait commentary and possible explanations
from y'all. Upon my return to the hangar (today was MY Sunday)
hopefully tomorrow night after work I will be looking at my, apparntly piss
poor, wiring.
As always my friends, Thanks.
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