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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