Chris, you must be the token target for
all the ill winds regarding rotary in aircraft.
If you are using the TES Teflon Encased
Silicon “O” rings, I would be surprised if they have failed under
the circumstances you have described. They can take a LOT
of punishment.
In a “freak” incident, I had
the triangular part of an apex seal drop down to the side of the rotor (fell
into one of the lightening holes milled in the rotor) and caused such heat from
friction that it turned the iron housing metal blue for an area the size of a
silver dollar or so. That much heat did cause compromise of the O ring in that
area but for only a very small segment (approx ½ -3/4” long) where the O
ring had shriveled into a thinner cross section. As Tracy, pointed out these “O”
rings can be somewhat difficult – well, at least they take some care- in
positioning them in the grooves and then assembling the parts without them
falling out of position. I use Halamar gasket sealer to hold mine in place.
For what it’s worth, I have seen the
situation where after a number of days of very cold weather I would get a seep
of coolant through the exhaust. It was a small amount and after firing up the
engine and running it the leak would not re-appear. This was shortly after a
rebuild so not certain whether the O rings had not yet seated in the grooves
completely or what – but, it did go away.
So unless you have warped or side housings
damaged in the area of the groove, the only likely cause I can think of it the “O”
ring fell out of position and got “pinched”. Since you indicated
new housings that are an unlikely source of the problem. However, if you do
take it apart, check inside the “O” ring grove with a metal dentist
pick to see if it catches on anything. If it does examine that area very
carefully to make certain there are no cracks. In some cases, cores apparently
shift in casting and can lead to very thin areas around these grooves and they
can be relatively easy to damage if you for instance drop a side housing on
that edge.
Good luck, hope you find you don’t
have to tear the engine down. I’ve be come rather good at it, but don’t
recommend it as a skill to acquire {:>)
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Christopher Barber
Sent: Monday, January 26, 2009
1:41 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Frying pan
into the fire....Arrgh
Perhaps one day I will post with good news. However,
today is not the day. I have really been having some fun as I move my project
from "proof of concept mode" to "flight prep mode".
The engine and wires have been my focus since I had to rebuild the strakes in
my Velocity following my Jeffco failure. (BTW, I may have discovered the
reason for my Jeffco failure...more on that later).
Since I have seemingly gotten most my electrical
gremlins tamed as in the engine running, the alternators charging and lights
working properly, I was gonna start to actually hook up my Dynon D-100, radios,
GPS's and audio panel today. I was also gonna take out my EC2 and EM2 to
send to Tracy
to check out one last time (my EM2 backlight stopped working so I figured I
would send it all in now while I tied up loose ends).
Since I was about to send my computers in and would not be
able to run the engine for a while I couldn't resist pushing the plane out of
the hangar and crank her up. She started up as expected. I taxied
around a bit making my "airplane" into a loud and expensive
"go-kart". I shut down after a few minutes as the temps started
to rise.
I let the bird sit for a bit and wanted to restart it.
Hmmm, not starting. Hmmmm. Let is sit a bit more. Try again.
Still no joy. I sat there for a minute and remembered it was a bit
difficult to start a second time the last couple of times I ran the
engine. UHOH! When I had to build this engine it was premised by
the old engine not wanting to start after an initial run. The first engine
got too hot and was leaking coolant into the rotor housings.
I took a big breath and went back to the exhaust.....there
was a bit of dirty liquid at the exhaust tip. Damn. Ok, take a
deeper breath and be a man (no offense Chrissi...I am a man<g>) and go
remove a sparkplug and take a look. Sure enough I removed the leading
plug of rotor two and it had a bit of liquid. I hand turned the prop and
steamy liquid blew out the hole. Damn-it, damn-it damn-it! Coolant in the
housing. Checked the front rotor and same thing, but less liquid. Damn.
Ok, when this happened to my rebuilt first engine I blamed
myself as I was in a serious learning curve. I ran it hot without a prop,
too hot with a prop and without proper sensors. I really should have
been surprised if I didn't fry it. So, when it failed it gave me an
excuse to buy new housings, end and center plates etc and build what was/is
essentially a new engine. I TOOK EXTREME care as to not to ever let it
get too hot. I would shut it down if it got between 210 and 220.
ONE TIME it got to about 225 degrees before I shut it down and that was only
for a matter of couple of seconds. None the less something has happened
to cause coolant to enter the rotor housings again. I used what were
advertised as "beefed up" O rings purchased from Pineapple racing
(kinda as a thanks to their rotaryengine illustrated website). It is
my understanding if that if the engine gets too hot these "O" rings
fail and let coolant seep through. Oh, I sooooooo hope it is just the
"O" rings and the hardware was spared. All the hardware is new
and professionally ported by Mazdatrix to a medium street port...I really was
developing some power.....
I spoke with my engineer friend, Blaine, who owns a couple
of aviation business with R&D as a major factor as well as building a
Soob/Eggenfielder RV-7 and he and I are gonna look into what I
missed. Verify that my sensors are working properly, check the cooling
system for proper flow again among other things. Very frustrating
though. I am, however, getting very good at removing my engine from
the plane. I had it off and sitting on the work table in only about an
hour. I am not gonna crack the engine open yet until I can get Blaine over for some
joint brain duty. On a positive note, there are a number of things at the
"firewall aft" that I need to address, this is giving me the perfect
opportunity to do so. They will be much easier to improve with the engine
off.
Now to resign myself to yet another engine build as we
determine the why.
And, as to another "why". I may have
determined why my Jeffco failed in my fuel strakes. As loyal fans may
remember I had to remove all the old epoxy/Jeffco from my strakes and redo them
completely a couple of months ago due to the Jeffco peeling away. Well,
as I was poking around the hangar looking for something I had placed as to be able
to find it easy later......yeah, right, I came across my old Jeffco
bottles. Hmmmm, the Hardener is labeled 3191 and the Resin is labeled
9700. Now, I remember that when I ordered it a few years ago it was
9700. I remember specifically as when I first ordered from AS&S they
sent the wrong stuff and I returned it for the 9700. THIS time I ordered
new Jeffco, but choose not to use it and just use straight EZpoxy for my
strakes, however, in the new order BOTH the Hardener AND the Resin were labeled
9700. My current thought is that I used the Hardener that AS&S
supplied with the kit assuming (yeah, bad Chris for assuming) that it was the
correct one to use with the 9700 Resin....which is what I knew to be the proper
number. It was not until the new order arrived a few months ago and I saw
both the hardener and resin are both 9700 and finding the original bottles from
a few years ago that I would have ever discovered a problem.
I intend to send a email to the company that bought Jeffco
and see if they can verify this conclusion.
As always y'all's insight, commentary, Wild ass guesses and
demeaning remarks are anticipated and relished. Please though, no gee
Chris, you sure seem to be having a lot of problems. Yes and No...I just
like to share more <g>. In the tradition of John Slade, share it
all, it can only help. Heck, this is the time to break things. Much
easier to deal with now in my own hangar and not on some deserted strip or
worse yet, in the air....even if my wallet is screaming.
So, the fun starts when???????? :-)
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