|
Ed,
It could be their rotors don't exceed the
tolerances - by design or just luck!
Also we are running continuous high power, unlike
cars, so advice on what's acceptable in cars, do not necessarily relate to
Aviation.
I picked-up a number of damaged rotors from the
local Rotary shop and all the damaged rotors which quite obviously suffered
broken apex seals, which destroyed the rotors and quite obviously the rotor
housings - had out of spec slots. There were some that seemed
good 9.7:1 rotors until the apex seals broke - they do a nasty job on the inside
of the motor!!
If your anything like me Ed - when there's a
lemon I'm gunna get it!!
I just live with that knowledge, and check
everything now.
It's any easy thing to check!
George (down under)
Well, George, I would not take the
conclusion that far. We have folks flying with several hundred more
hours than I have with no apex seal failures. In fact to the best of my
knowledge, I am the only one I am aware of other than Chuck Dunlap who's
rotary engine swallowed a 1/4" dia steel bolt (it was retained - so we know)
to have an apex seal failure in an aircraft. However, I do believe that
folks need to be more aware of the true condition of their used engine
components - I know all probably did was look at it and not seeing any
obviously defects or dings said - "good to go!"
As you know, Leon is convinced my apex
seal failure was also due to foreign object ingestion - I certainly can
not prove it was something else (like the apex seal slop) although
I don't believe a foreign object to be the case - belief is not a
fact {:>).
Ed
----- Original Message -----
Sent: Friday, April 22, 2005 9:44
PM
Subject: [FlyRotary] Re: All Parts have
arrived, Whew!
Ed,
Good thinking and good to get the
feed-back.
I do believe we are starting to see a trend, in
regard to apex seal slot wear. I believe the problem is that it's
starting to give the rotary, for Aviation use, a bad name, and it's the sort
of thing that could easily do it.
When you think about it, too much slop is going
to aggravate the apex seal side wear, which could have resulted in
those chatter marks.
George ( down under)
George, the rotor housings had some wear -
but no gouges or groves, no missing chrome - so they were probably OK to
reuse again. However, there was what appeared to be "chatter" wear -
strips across the chrome at regular intervals. When you rubbed your
fingers along them I could detect a faint wave like pattern (valleys and
peaks). So decided with new rotors and seals to go with new rotor
housings. Those were used ones and who knows how many miles they
might have had.
Well, I was quite surprised at the amount of
wear on the seals - they were brand new 150 hours ago but the seals
were badly grooved and worn - now I am certain that wear was greatly
accelerated by the poor condition of the seal slots - but still. In
any case, new stronger seals are going to be used next - as well as
additional of an air filter. I personally don't think an airfilter
would have made any difference in the apex seal breaking - but, I also
noticed that the rotor metal oil rings were worn outside the specs and
they were new 150 hours ago. So I do believe I have had some
accelerated wear due to the dust in and around my hangar over the past two
years. Since a filter is cheap, I'm going to stick one
on.
Ed
----- Original Message -----
Sent: Friday, April 22, 2005 6:23
PM
Subject: [FlyRotary] Re: All Parts
have arrived, Whew!
Ed,
Were the old housing junked because you
spat the apex seals?
I just got a report that one bloke in
Victoria Aust is only getting 200 hrs out of new seals before they break
- I wonder if it's the same problem? I'm pretty sure it
is!
George ( down under)
Ok, folks, the fun begins. Got the
last of the parts in today, so can start the assembly
tomorrow. Waited for UPS to deliver the oil control rings all day
- so was down in the dumps when 1600 rolled around and
no UPS truck. So maundered down to the mail box and
their wedged into its opening was a USPS package - not
UPS!
Going to sit down tonight with a bowl of
pop corn and watch Bruce T perform the assembly part. I
noticed that the transcript did not have anything on the reassembly -
so assume that I either got tired of listening to Bruce, figured that
the assembly was just the reverse of the disassembly - or lost that
part.
Got all the rotor parts in plastic
sandwich bags marked for which rotor, which side of rotor and which
apex. For most parts it really doesn't matter but, for instance,
is very important when replacing the oil control seals to put the
springs back correctly according to direction of rotation and side of
the rotor. Also important on the side seals to get them in the
right slot or else all that work trimming the side seals to get that
precision fit is lost.
First time I've actually had new rotors
and housings - I like the looks - though not necessarily what
they cost. But, Bruce gave the best price out of three
quotes I got. Just wanted you to know.
Ed
|