I didn't know about the requirement to replace the lower spacers but I have
no technical objections to the S-beam mount other than to pay careful attention
to the rear mount requirements as Jerry pointed out. I have seen Jerry's
work before and if the precision on the new spacers is as good as I expect, it
should be no problem.
As he also noted, the arrangement of cooling and exhaust systems will be
greatly affected by your choice of engine mount style. Know what you are
doing before making the choice. (didn't really need to say that did I?)
I would (strongly) not recommend using the redrive adapter plate
as the engine mount.
Tracy (still waiting on my 20B right hand offset CCI engine
mount)
----- Original Message -----
Sent: Sunday, January 16, 2005 10:21
AM
Subject: [FlyRotary] Engine mounts
I do build rotary engine mounts as many of you already
know. It
started out a couple of years ago with the Motor Mount
Plate concept.
That was abandoned when Bill Schertz invented
the beam mount which is
much better in every way. Lighter, stronger,
cheaper. In response to
an inquiry yesterday, I sent the
following info, that I would like to
share with every one. The
question was could I supply an engine mount
for the RV6 tri
gear.
The short answer is Yes. The engine mount I build
is called an S-beam
(Schertz Beam) mount. The concept was first
developed by Bill Schertz
and was modified by Paul Lamar and others until
it evolved into the
present configuration. The S-beam mount only
supports the front of the
engine. The rear engine support is
provided by a adjustable strut
that runs from "someplace" on
the back of the engine to "someplace" on
the firewall. The
"someplace" varies from plane to plane. For some
aircraft, such as
the Kiss Cruiser that have a plywood firewall, it is
no problem at
all. For others such as the RV, the sheet metal firewall
may have to
be reinforced where the strut attaches. I say "may"
because it might
be possible, in your case, to tie into the nose gear
assembly
instead of the fire wall. I do not provide the rear strut as
part of
the engine mount package. It is easy to build.
Another
complication is that the starter has to be relocated from 6
o'clock
(on Tracy's drive adaptor plate) to some other position such
as 3 o'clock. The reason for this is that the S beam blocks
the 6
o'clock position. If you are planning to put the radiator
underneath,
then you probably would want to relocate the starter
anyway. If you
are thinking of using cheek radiators, then moving
the starter to
either side may not be a good idea. Each Installation
has to be
evaluated individually.
A third issue is that the S Beam
replaces the lower spacers that Tracy
supplies with the drive.
I have not asked for nor received
permission to do this from Tracy
and he may well void the warranty on
the drive. If our positions were
reversed that is what I would do. The
steel spacers I use with
s-beam are precision ground to .5 thousands
of an inch tolerance.
Relocating the starter requires welding an
extension on the drive adaptor
plate which I can also do. Once again
this has not been authorized
by Tracy.
If you decide to have me build the engine mount,
I will need a
physical template of the engine mount attach points on
firewall and I
will need to know the distance from the firewall to the
face of the
prop flange on Tracy's drive.
The S-beam engine mount
was developed to make it easier to put the
radiator under the engine and
to fit the exhaust system including
turbos.
The cost, including
starter relocation, is $850.00. A fifty per cent
deposit is
required. The balance can be sent when the engine mount is
ready to
ship.
Normally it takes about one month to build an engine
mount. Jerry
P.S. I do not build engine
mounts Jan and Feb as the shop is too
cold.