Paul,
 Thanks for the info for ordering the Versa Mounts. While I'm
 placing an
 order with McMaster-Carr, I thought I would also buy the teflon for
 the slide
 throttle. There is a lot to choose from and its pretty confusing. Do
 you have a part number for the stuff you recommend ??

 Don

 There are two ways of doing it. Make the slide out of solid
 Teflon 3/8th of an inch thick which is the old expensive way.
 3/8th comes in cheaper low tolerance material or more
 expensive close tolerance material... probably milled.

 The cheaper way is to make the slide out of 1/4 inch thick
 aluminum and use a layer of 1/32" Teflon on either side.

 Here is the procedure for doing that thanks
 to Craig Smith. It is also the way our kits for the
 two rotor are done.

 This is the stuff I recommend.
 http://www.mcmaster.com/#plastics/=5yakjv

 Paul Lamar




 Thanks Paul,
 That link takes me to the main index area that I was finding before.
 These are the materials that come up when I search for Teflon :

 Don

 This is the stuff you want.

 Virgin Electrical Grade Teflon® PTFE


<http://www.mcmaster.com/param/asp/psearch.asp?FAM=plastics&FT_138=117610&FT_130=641&FT_101=50336&FT_1215=48565&FT_1199=87677&session=plastics;1215=48565;101=50336;138=117610;130=641;1199=87677

<http://www.mcmaster.com/param/asp/psearch.asp?FAM=plastics&FT_138=117610&FT_130=641&FT_101=50336&FT_1215=48565&FT_1199=87677&session=plastics;1215=48565;101=50336;138=117610;130=641;1199=87677>


<http://www.mcmaster.com/param/asp/psearch.asp?FAM=plastics&FT_138=117610&FT_130=641&FT_101=50336&FT_1215=48565&FT_1199=87677&session=plastics;1215=48565;101=50336;138=117610;130=641;1199=87677

<http://www.mcmaster.com/param/asp/psearch.asp?FAM=plastics&FT_138=117610&FT_130=641&FT_101=50336&FT_1215=48565&FT_1199=87677&session=plastics;1215=48565;101=50336;138=117610;130=641;1199=87677>>>:

 Made with virgin Teflon® polytetrafluoroethylene (PTFE) resins, this
 material surpasses most plastics when it comes to electrical insulation
 properties, low friction chemical resistance, and performance in
extreme
 temperatures.

 Thew glass filled stuff is a no no and that may have happened
 with Mark Steitle and why he noticed higher throttle cable forces.
 We actually tried that and I was rather disappointed in the
 friction performance.


 Paul Lamar

Paul,

Did you have a chance to look into the friction coefficients of the
various types of teflon? Everything I look at on the McMaster site
states a friction coefficient no greater than 0.2.
I reduced the thickness and width of my teflon slide to give a little
more clearance for thermal expansion. But that won't help with the high
forces at low throttle settings. I was wondering if anodizing the
inner wear surface would help with that problem.
Mark S.
Austin


P.S. No I didn't know Joseph Stack. ;-)

Sorry Mark about your problem. I thought I discussed all this years
ago when we first started. I'll have to update the web site and
add a caution.

I know the glass filled stuff is not good as I tried it.

I used the old printed catalog #108 Page 3281 and 3282.
"Precision ground blanks." "Very low friction."
My guess is that means it is around .05.
Unfortunately they said that about everything which
was a lie :) The expensive stuff I choose for Mark Supinski's
slide was no problem.

Tolerance on 1/32" thick is .003" The 3/8th inch thick is real
expensive at $138 for a 12" by 24" sheet.
That is why I changed to 1/32" thick and an aluminum slide.

I have no idea about anodizing. I doubt it however.

If you put coefficient of friction Teflon In Google
http://hypertextbook.com/facts/2004/GarvinTam.shtml
Here is a jpg.

Use a fish scale on the throttle and see what force
it is taking.

Here is an idea to fix yours. Get some 1/32" and sandwhich
it in there. It will be Teflon on Teflon.

Joseph Stack? What about him?

Paul Lamar



Paul,

I had been wondering if teflon on teflon would yield a lower coefficient
of friction.  According to the chart, it shold reduce it considerably.
I'll do a test and see if that could work.

That comment about Joseph Steck was my attempt at a bit of humor.  He
was the pilot who flew his Cherokee into the IRS building in Austin last
week.  Knowing that I'm a pilot, many of my co-workers, casual
acquaintances, relatives, etc. had to ask if I knew him.

Mark S.