X-Mozilla-Keys:                                                                                 
Mike Wills wrote:

  Well the more comments I read on this the less enthused I become. Ive
spent some more time eyeballing the engine and the stock mount and I'm
beginning to think this is more trouble than its worth. Since I'm really
not qualified to engineer it the tendancy would be to overbuild it with
lots of bracing to the engine block. On the right side thats easy but on
the left side much more difficult. And in the end  if overbuilt its
probably going to be heavy though I still think it can be built to be
comparable to Tracy's submount weight of 13 pounds. Im going to continue to
sketch on this and will probably still mock up a prototype but Im also
going to look at a more conventional mount. The real benefit to this design
is the amount of space it frees up under the engine for radiator and oil
cooler. If I use a conventional mount Im going to have to totally re-think
my cooling system.

  Another option would be to build a welded submount from 4130 that bolts
rigidly to the stock Vans mount with arms that project out parallel to the
oil pan rail. Something like Paul's hat section and rubber bushings could
then be attached to the engine/PSRU/prop cg. The engine could then be
bolted through bushings to the ends of those arms. This would probably
still weigh around 12 - 15 pounds but would still preserve the stock mount
and free space under the engine. Of course this would require some
triagulation between the horizontal and vertical members of the submount
which again would be tough on the right side. I'm going to look at this also.

  To James Phillips: this design will weigh more than a conventional mount
and it will place the prop flange about 5 inches further forward than a
Lyc. The forward cg would likely be a problem on an RV6. Less likely to be
a problem on the RV4 which tends to be tail heavy anyway but it is
something Ive worried about. Vans factory mount is sure a nice piece of
work and its gonna be tough for me to force myself to cut it up.

  Paul, I would be interested in seeing any other drawings you may have on
your planned mount and hat section. Post them or email them direct,
whatever is most convenient for you.

Thanks for all the input on this,

Mike Wills

I will have to do some part drawings soon as I am getting ready to have
some hat sections bent up and welded.

Paul Lamar
 
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