The Murphy Builders Site

Good stuff, Paul !

Using the AIL-26 brass bushings on the elevator & rudder end
supports is now pretty much a standard mod. It is important to
use the nylon 'pog' washers at the ends, between the end caps
and the bushings, to ensure that there is no end play, and to
protect the bushings from the rivet heads, especially on the
bottom of the rudder. I think Wayne still supplies these ....
The bushings have their flanges turned down in a lathe, so they
don't stick out much beyond the support, and, as Paul has done,
are pinned in position with a countersunk rivet - and some have
used a bit of Loc-Tite on install, as well. The flange faces
inward in all brackets.

For those who have already finished their control surfaces -

Don't worry - just GET IT FLYING !!!

While several new builders are adding these bushings as they
build, it's NOT urgent. Even if you DO add them now, you WILL
need to replace the bushings at SOME time interval....

The 912 Rebel went about 1,000 hours and 10 years before
it needed the bushings - it's a combination of the engine/prop
combo, and the kind of flying you are doing, and the environment,
that causes the wear. (The tail shakes a lot when on amphibs,
and a lot of sand isn't good for anything ...)

We only had about 250 hours on the O-320 Rebel before there was
enough wear to warrant dis-assembly & installing the bushings,
but there were extenuating circumstances - like a failed trim
tab horn that resulted in severe elevator flutter through a
looooong descent from 7,500 ft. or so ... compounded by elevator
tips that were thin fiberglass that was flexing - we added .032
strips about 2"+ wide inside them for stiffness, and extra counterbalance.
I add a drop of oil to each of these bushings every month or so
during pre-flight ... and after washing the Rebel to remove dust.

Maybe we need to add this one to the list of "Ontario Mods". ;-)

--
......bobp
http://www.prosumers.ca
http://bpatterson.qhealthbeauty.com
http://apatterson2.qhealthzone.com

-------------------------------orig.-------------------------
On Thursday 30 November 2006 09:15 pm, C&P Kucera wrote:

I ordered and installed the same brass bushes that are used on the
flaperons. I reamed the aluminum brackets for slide fit, press fit would add
stresses. To stop the bushing from rotating I put in one 3/32 solid flush
rivet thru the bushing flange and the bracket. I had this OKd by MAM.
------------------ snip ! --------------------------------------

My elevators and rudder ride on the flanges of the bushings.
I only did all this because I saw some significantly worn bracket holes on
some well enjoyed Rebels.

Now Im just building by the manual, no improvements at all except for "the
must do Rebel beef-ups", so that I get it done and flying.

Paul K
Mississauga
rebel 453R


----- Original Message -----
From: "Jones, Michael" <Michael.Jones@snclavalin.com>
To: <rebel-builders@dcsol.com>
Sent: Thursday, November 30, 2006 8:47 AM
Subject: RE: [rebel-builders] Horizontal Stabilizer

Ken

Believe on builder from stoney creek put brass bushings in all locations
on
tail feathers, might have even been approve by Murphy but it would have to
be confirmed to be sure

mike

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Thursday, November 30, 2006 8:30 AM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Horizontal Stabilizer

The thing is that the bolt itself has little ability to resist side
loading or wobble. It is the 3/8 steel bushing tight against the spar
cap that provides most of the resistance to side to side movement of the
bolt. I would not be comfortable simply replacing the steel AIL-26
sleeve with a plastic part.

The other proposal made from time to time is to bush the holes that the
AIL-26 goes into. Except for the bottom of the rudder, I'd guess that
the 3/8" id x 1/2" od flanged bushings would be fine. It does not sound
like this is really a high wear area though and my aluminum brackets
don't have a lot of extra metal there to drill out. The next question
would be - can you actually source the bushings without buying a
thousand of them, or do you have a lathe to make your own? The flange
will take up a bit of space if the control surface is a tight fit. Wayne
might comment, but I consider most of those plastics with various trade
names like acetal, acetron, etc. to be equivalent to delrin. Anyway I
built to the plans, assembled them with grease, and will bush them later
if they wear.

I did put a brass bushing at the bottom of the rudder though. That
lower bushing does have higher loading than the others and it does
collect a lot more dirt ,oil, and water, than the others. Maybe it
wouldn't collect the dirt if it was plastic and dry instead of oiled but
in my mind the loading might be a bit high for plastic??

Ken

rognal@dcsol.com wrote:

Question: If the Rebel rudder/elevator pivot bolts/bushings/brackets are
high wear areas, and if these bolts/bushings do not need to be "too
tight",
why not replace the steel bushing(s) with a synthetic (?) bushing such as
these:

http://qbcbearings.com/RFQ/B610HTML/B610P116.html Plain sleeve
bearing/machined acetron/non-metallic/self-lubricating,

Or http://qbcbearings.com/RFQ/B610HTML/B610P118.html Plain sleeve
bearing/non-metallic/teflon

Or something similiar ie; nylon, delrin, etc.

I have no real familiarity with the properties of any of this material,
but
it seems I've seen most of it described as having high wear and self
lubricating properties.

Under 'not too tight' conditions could these synthetic bushings be
suitable
as a replacement bushing with no need for additional lubrication.

Thanks for any comments.

Roger Hoffman #687R
Eugene, OR USA!

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