Fuel/Water, Bearing/Rust

Sat Dec 6 07:12:29 AKST 2003

Think about this. Have you ever seen bearings rust in a tank with aluminum tubes and no clunk as in a Tetra bladder tank setup ?? I've seen it, Dave Funk's OS 140RX in his Hydeaway rusted the original bearing in very few flights. IMHO I wouldn't expect bearings to rust in a container of clean unburnt fuel just because of the roughly 20% oil content. I do agree the fuel breaks down into some sort of compound that along with type and mix of materials used in many of our glow engines promotes some form of corrosion. If you look at the YS engines it is rare to see a rusted wrist pin or crankshaft, IMO due at least in part to the different plating YS does to their engine components. Dave Funk and I had to replace the aluminum tubes in my year old Tetra tank at the Sydney NY contest late Saturday evening, the fuel supply tube was black as coal and broken off in the tank right where it entered the rubber stopper. I have never seen that happen with brass tubes in the tank. Seems we all forgot the days of the piped 60's, we all had bearing problems back then. The only engine from the factory that I didn't have a bearing rusting problem was my YS61AR which at least my engine came with a pre-lubed stainless steel rear bearing with 2 SEALS. But my YS61 long stroke would rust a standard rear bearing in the time it took to consume a cup of coffee. I know Dave Lockhart has hundreds of flights on a OS140RX w/a stainless rear bearing with 2 seals, in Boca Bearing talk "2RS" not metal shields which are designated "ZZ". The fact he has hundreds of flights on those sealed stainless rear bearings also dispels the myth the rear bearing on the OS140 is undersized IMO.
Ed M.

  ----- Original Message ----- 
  From: Bob Pastorello 
  To: discussion at nsrca.org 
  Sent: Saturday, December 06, 2003 10:11 AM
  Subject: Re: Fuel/Water, Bearing/Rust

  Good point, Bill.
      Does anyone KNOW if the "brass corrosion"/conversion into acetic acid is the REAL deal?  How can we find out?
      Wouldn't it be bizarre if the corrosion on bearings issue was due to something like this?

  Bob Pastorello, Oklahoma
  NSRCA 199, AMA 46373
  rcaerobob at cox.net
  www.rcaerobats.net

    ----- Original Message ----- 
    From: Bill Glaze 
    To: discussion at nsrca.org 
    Sent: Saturday, December 06, 2003 9:48 AM
    Subject: Re: Fuel/Water, Bearing/Rust

    Bob:
    You might want to take a look at the plated clunks occasionally, I've had the plating break down, (possibly from vonstant vibratory contact with the bottom of the fuel tank) and then the brass begins to corrode.  Bill Glaze

    Bob Pastorello wrote:

Also, most clunks I've seen lately aren't brass-looking.  They apparently
are plated and look shiny-brite metal.  I've drilled some of them, to find
they're brass underneath.  So that sort of begs the question, WHY would fuel
tank manufacturers add the expense of plating a KLUNK ??
    My Mintor setup has no brass that I can see; it will be interesting to
see how this goes.  Has an MK tank, aluminum tubes, nylon tees in lines.
Plated clunk in the tank.

Bob Pastorello, Oklahoma
NSRCA 199, AMA 46373
rcaerobob at cox.net
www.rcaerobats.net

----- Original Message ----- 
From: "Brian Young" <b4598070 at yahoo.com>
To: <discussion at nsrca.org>
Sent: Friday, December 05, 2003 7:45 AM
Subject: RE: Fuel/Water, Bearing/Rust

Cant remember if the fuel needed the water in it to
break down into acetic acid..anyone recall?   ;0

I have had older brass clunks corrode the nipple off
at the end of the tubing.....I have noticed the little
green brass particles plugging up the ports on some of
my engines....always wondered why they used the brass
for this stuff. I use plastic or aluminum if I can,
and steel clunk if available.

--- Dwayne & Nancy <dwaynenancy at cox.net> wrote:

Bob, Joe said that blaming water in the fuel as the
cause of bearing
rust was a "folk tale".  The cause was the fuel
decomposing into acetic
acid (vinegar).  The decomposition is caused by the
catalytic effect of
the brass components inside the fuel tank.  Joe
tried leaving bearings
in several brands of fuel for four months without
any rust forming.  You
should read the magazine more carefully.  You can't
tell when something
valuable with show up.  <VBG>  Dwayne

-----Original Message-----
From: discussion-request at nsrca.org
[mailto:discussion-request at nsrca.org]
On Behalf Of Bob Pastorello
Sent: Thursday, December 04, 2003 8:25 PM
To: discussion at nsrca.org
Subject: Re: Fuel/Water, Bearing/Rust

Okay - Matt - since my MA already found it's way to
the shredder....
    WHAT did he say about rust protection?

Bob Pastorello, Oklahoma
NSRCA 199, AMA 46373
rcaerobob at cox.net
www.rcaerobats.net

----- Original Message ----- 
From: Rcmaster199 at aol.com
To: discussion at nsrca.org
Sent: Thursday, December 04, 2003 6:11 PM
Subject: Fuel/Water, Bearing/Rust

The diatribe of the last week or so on this list has
been, shall we say,
rather........ interesting, (except for the news
about Kirk Gray, that's
plain sad). It's time for something new.

In this month's Model Aviation, Joe Wagner talks
about experiments he
has run with a trusty old engine. He ran baseline
performance data with
his regular fuel and then he added water in his fuel
to see how badly
performance would be affected. His results where
very interesting. Shall
we say that he made chopped meat out of that "sacred
cow".

He also briefly touches on what really is the root
cause of bearing
rust. Even the uninitiated should find that
interesting. Could a
solution to all of your OS bearing woes be this
simple?

There, that ought to whet your whistle.

Matt K

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