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Re: [TowerTalk] Add on 3" mast brake?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Add on 3" mast brake?
From: SSC - Mitch - VE6OH - CIW308 <ssc@andor.net>
Date: Thu, 17 Nov 2022 15:33:01 -0700
List-post: <mailto:towertalk@contesting.com>
Grant,

Mitch here from Alfa Radio

Don VE6JY did a lot of experimenting with shock absorbsers when he had has big 80 meter beam.

You could something like that.

I have made one from a torque disk (replaces a universal joint) on many import autos.

I used one for a Mercedes Benz - They are good for many hundred of horsepower and they are exposed to the ground so goods for all weather.


That and the Big Rak rotator my solve your problem.


Mitch  VE6OH




On 2022 Nov 16 08:37, Grant Saviers wrote:
Searched for the BMW driveshaft damper part - $1200 from BMW with a $500 discount, $31 on ebay.  Could there be a quality difference  ;) ??

Also, could make one from multiple threaded end (plate/plate) vibration isolators, but that would cost more.

https://www.mcmaster.com/64885K33 or Kipp from MSC

https://www.kippusa.com/xs_db/DOKUMENT_DB/www/KIPP/BEDIENTEILE/Technische_Hinweise/enUS/TH_009_Gummipuffer_enUS.pdf

Grant KZ1W


On 11/16/2022 06:10, jim.thom jim.thom@telus.net wrote:
M2, at one time, did offer the BMW rubber coupling isolation assy, for
their OR-2800  rotors. The rubber coupler was sandwiched between 2 x new
plates.  The 2 x new plates were bolted  between the oem drive plate...and
the oem mast clamp assy.

When I went to buy it, I was told it had been discontinued. Reason given
was hams  were....'not doing proper maintenance' on the completed assy. The
various new bolts were loosening up everywhere.

Permatex now makes... 'orange'  threadlocker. It's as strong as ..'red'
but easy to get off like ...'blue'.  IE: No heat required.  That would
probably have done the trick.

Shorting the windings on a DC motor is a simple idea, superb. On my small (K7NV + RT-21) prop pitch, it has 2 x windings, so both windings would have
to be shorted, non issue, moot point.

Yaesu at one time offered an..'anti vibration pad' that was installed
between the base of their rotor..and the  rotor plate. IMO, it won't do
much of anything.

Still another method that was used back in the 60's and 70's was 2 x masts, one inside the other, with a good overlap...like 1'.  A coil spring, like used on the front end of a car's suspension, was slid over the overlapping mast tubes.  Top of the spring was welded to the upper mast...and the lower end of the same spring was welded to the lower mast.  There is just enough
compliance between the 2 x mast sections, that the spring absorbs the
vibrations.  It worked on the same idea as the BMW rubber coupling.

The drawback of course is the 2 x tubes are not bolted together, and the
top mast tube must be able to freely rotate inside the lower mast tube. The
overlapped portion was lubricated.  Welding required.    The assy was
installed between the rotor plate and the top plate. The main mast tube,
(the long, main  3rd tube), was slid through the top plate..and coupled to the   2nd tube.  It worked, but I only knew of a few instances where it was
used.   The BMW rubber coupling version would be easier to implement,
install, and / or replace if required.

Jim  VE7RF
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