> > > >  > Here is an interesting subject that I have not seen
discussed in my

 > > >>  years on this list.
 > > >>  Has anyone tried to duplicate the overriding clutch or whatever it
 > > >>  is/was on the "twin pack" rotary set up done by that European outfit
 > > >>  several years ago? Can't remember the name (Swiss company?), I think
 > > >>  they are out of business. Anyhow, it seems a very elegant
solution to a
 > > >>  high hp redundant twin, esp for helicopters or even a
large cabin class
 > > >>  craft.
 > > >>  How did that tranny work? The engines were side by side.
 > > >>
 > > >>  BTW, any word on those PT6 gear drives?
 > > >>  [Marc Wiese]

 > >    From Ken Welter
 > >   Yes I have here is a photo of my twin pack that will go on the 4
 > > place coot that I am starting to build, I installed this pack on my
 > > present coot and tested it for 11 hrs and was a bit heavy for it but
 > > should work on the bigger one, the front engine is a 670 Rotax
 > > snowmobile engine that puts out 125 hp but there is no reason that it
 > > should not work with two rotary's however part of the design to stop
 > > resonant vibration is to run two very different rpm's so you would
 > > run two different gear ratios and I would suggest running a 12a and a
 > > 13b, the spag clutches that I used were made by SSK and sold by Morse.

 Ken we just realized what this message was all about.
 We have been looking at a way to run a pair of rotary's together
for a helicopter

 engine.
 Do you have any more details, pictures, drawings etc on this setup.
 Royce

  From Ken Welter

   Unfortunately as a eyeball engineer most of the blue prints are in
my head and I have not found a modem cable to download it into my
computer yet but I will give you the basics of it. The key is to stop
resonant vibrations and to do this I mounted the engines separately
on rubber mounts rather than mount the engines solidly together and
then rubber mount them as a package. That is the reason for the CV
joints and axle so they can float independently and also run the
engines and different RPM's. Ideally have two different types of
engines so that they have different resonant frequency's. That is also why
I say run a 12a and a 13b. I would run the 12a at say 6500 rpm while
the 13b would be at 5500 to 6000 rpm.

  As for the clutches I ran a sprag on the Rotax, that is the drum
looking thing that the CV joint is connected to and I ran a dog
clutch on the Mazda but that would not work for your application. You
would need a sprag on both. For information on sprags check out a
Morse catalog. They have all the engineering data on them also if you
need custom pulleys I make them for the redrives that I  sell check
out my web page at http://homepage.mac.com/rotarycoot/

 
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