Another bearing question....

[george kennie]

Hey Wayne,
I believe ya, buddy. I'm just trying to understand the scientific reasoning
behind the phenomenon.
G.

Wayne Galligan wrote:

> Georgie,
>
> The key word there is "possible bad bearing"  I can only assume that it may
> have something to do with the vibration the bearing makes at that particular
> rpm or something. I really dont know.  All I know is that when it starts
> happening on my OS I was having a bearing problem that I confirmed by
> wiggling the prop at the tips and had some end play.  It did not have the
> rough feeling when turning spinner. Replaced the bearing and it ran perfect.
> Didn't mean to confuse...   Perhaps there is a more technical explanation
> for it.  That's just my experience with this particular engine.
>
> Wayne Galligan
> ----- Original Message -----
> From: "george kennie" <geobet at gis.net>
> To: <discussion at nsrca.org>
> Sent: Thursday, October 23, 2003 1:03 PM
> Subject: Re: Another bearing question....
>
> > Boy, that blows me away! Somebody that's an engine guru please explain why
> a
> > faulty bearing causes the mid-range loading-up problem.
> > I have a 60 size engine that is a few years old that will turn a 12x7 prop
> over
> > 12K rpm and idles below 2000, and transitions beautifully, but if I run it
> up to
> > full power and let it run for about 30 seconds, at which time it sounds
> awesome,
> > and then reduce the throttle to 9000 rpm, it will run good for about 5
> seconds
> > and then start to load up and will quit, while at this setting after about
> 15
> > seconds.
> > It just happens to be sitting on my benchtop with a prop on it and I just
> went
> > in and turned it over. The bearing feels smooth, there is no slop in the
> prop
> > tips and there is absolutely no end play.
> > Maybe I should keep the bearing and order the rest of the parts to build
> up a
> > new engine.
> > Hmmmm, .........still confused.
> > Georgie
> >
> > Wayne Galligan wrote:
> >
> > > My OS will do the loading up in the midrange and die thing.  It has
> happened
> > > on the last two bearings thus giving me the warning.  Then of course I
> could
> > > verify the end play at the tips of the prop. Funny thing was I couldn't
> feel
> > > any roughness.  But after a fresh bearing it ran fine.
> > >
> > > Wayne
> > >
> > > ----- Original Message -----
> > > From: "White, Chris" <chris at ssd.fsi.com>
> > > To: <discussion at nsrca.org>
> > > Sent: Wednesday, October 22, 2003 2:55 PM
> > > Subject: RE: Another bearing question....
> > >
> > > > Thanks Wayne.... The first 2 I would expect, the 3rd is new to me, and
> the
> > > > fourth....well that kind of says why we care....:)
> > > > Chris
> > > >
> > > > -----Original Message-----
> > > > From: Wayne Galligan [mailto:wgalligan at goodsonacura.com]
> > > > Sent: Wednesday, October 22, 2003 2:47 PM
> > > > To: discussion at nsrca.org
> > > > Subject: Re: Another bearing question....
> > > >
> > > >
> > > > If you rock the spinner back and forth and it is not smooth or you
> feel
> > > > roughness.....bad bearing.   If you grab the prop by the tips and
> wiggle
> > > it
> > > > back and forth and there is end play.... bad bearing.  If you
> experience
> > > > sudden changes in the midrange like loading up and engine quits on
> spool
> > > up
> > > > and plug is OK....possible bad bearing.
> > > >
> > > > Or if you see metal filings coming out the exhaust....... TOO LATE bad
> > > > bearing and engine.
> > > >
> > > > Wayne G.
> > > > ----- Original Message -----
> > > > From: "White, Chris" <chris at ssd.fsi.com>
> > > > To: <discussion at nsrca.org>
> > > > Sent: Wednesday, October 22, 2003 2:32 PM
> > > > Subject: Another bearing question....
> > > >
> > > >
> > > > > Hi!
> > > > > I hear of guys getting anywhere from 35 to 400 flights on bearings:
> > > > >
> > > > > What are the first signs of bearing problems. Since starting
> > > Intermediate
> > > > > practice in July, I have just got into flying the same
> airplane/engine
> > > > > regularly enough to wear on an engine and tell the difference in
> > > > > performance.  I have 97 flights on a Zen/Webra 145AAR combination. I
> use
> > > > > Cool Power 15% and after run oil religiously.  I have a  tach which
> > > varies
> > > > > so much with light emissions that I deem it as unreliable.  So what
> do
> > > you
> > > > > look for?
> > > > >
> > > > >
> > > > > Thanks, Chris
> > > > >
> > > > > -----Original Message-----
> > > > > From: gene.maurice at comcast.net [mailto:gene.maurice at comcast.net]
> > > > > Sent: Wednesday, October 22, 2003 2:07 PM
> > > > > To: discussion at nsrca.org
> > > > > Subject: RE: bearing question
> > > > >
> > > > >
> > > > > Try WWW.AFCBEARING.COM. Great prices and so far a good product. They
> > > carry
> > > > > all of the standard sizes, but some of them have to be shipped from
> > > Japan.
> > > > I
> > > > > am using their sealed SS bearing in my OS 160 with the seals and
> grease
> > > > > intact. 120 flights (+-) without a problem. And I am using crank
> > > pressure
> > > > to
> > > > > power a Perry pump. This is after going through 2 sets of carbon
> steel
> > > > > bearings after less than 35 flights each.
> > > > >
> > > > > --
> > > > > Gene Maurice
> > > > > AMA 3408 NSRCA 877
> > > > > Plano, TX
> > > > > gene.maurice at comcast.net
> > > > >
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