> >>>Michael McGee wrote:
> >>>
> >>>>Doing some dreaming..
> >>>>
> >>>>What do you guys think of the viability of a front
cover
cast into the form
> >>>>of a standard Lycoming dynafocal-1 mount?
> >>>>
> >>>>A loose collection of my thoughts so far:
> >>>>
> >>>>I think it would sell well enough to get the price
under
$500 for the
> >>>>kit. I was bs-ing with the local rotary engine
builder
the
other day and
> >>>>he showed me a very nice third-gen oil pan that was
cast
as
a replacement
> >>>>for the stamped steel original. The reason behind
the
pan
is another story
> >>>>but the casting work looked great (from this
engineer/
non-casting expert's
> >>>>perspective anyway). He insists that he has a
casting
guy
that is capable
> >>>>of making what we need if I can get him a proto type
part.
> The idea behind this is fairly sound since it would
eliminate
some of the
> engineering rotary conversion folks go through. You need
to
control the price
> as much as possible to keep it attractive. Would this be
an
addition to a
> traditional dynafocal mount that basically adapts the
Mazda
engine to it, or a
> dynafocal-like mount with multiple pieces, that could
support
either engine?
> Would your front plate be enough to mount the engine
with, or
would we still
> need to fabricate additional support members to the far
side
of
the engine?
>
> Brock's Lycoming mount for the Cozy is $625. If your item
is
an
adapter to a
> dynafocal, it would cost me, as a builder, $1125 for this
combination. The
> Conversion Concepts mount (if you set aside Paul's issues
with
it for the time
> being) is $1098. That's not unattractive for a mount that
does
more (by
> allowing the use of either engine, making the plane
easier to
sell, or making
> retrofits easier). However, if the cost climbed much
above
your
estimate or if
> additional engineering was still required, it would be
harder
to
compete.
>
> With respect to the water pump, should I tease Paul and
suggest
an electric
> water pump? =)
>
> How serious are you about creating this? If you started
and
then
changed your
> mind after making a few, would you publish the
specifications
and a
> dimensional drawing? Knowing that a part will be
available
when
I'm ready to
> actually mount the engine is one of the factors a builder
has
to
consider.
>
> Regards,
> Chad
Have you considered CG issues??? When I looked at this a
couple
of years ago I considered building an engine adapter to fit the
standard
conical
mount (for a RV-4) but determined that the CG of the engine
would
be moved forward a significant amount. I don't remember the exact
amount, but I
think that it was about 2 inches.
Ken Powell
Once I get the mockup shaped out of Styrofoam I'll have a better
idea of
exactly where the CG will end up. I'm pretty sure it won't be any
worse
than an O-360 with a constant speed prop.
Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode, RD-1C, EC-2
Mike you might want to make it fit the RX8 engine. Here are some
pictures
of the RX8 front cover. If you can... move the stock water pump
cartridge
down along side the engine instead of up top. This minimizes the bad
effects
on the front cover when the engine is run at high speed with low water
levels.
More on that later.
It also gives a straight shot into the back side of the pump impeller
improving the pump efficiency..
Paul Lamar
Also note that the Renesis is ~20 lighter than the 13b (according to
Tracy).
Ken P.
I think that is ten pounds Ken and not twenty. Some of that is due to
the aluminum water pump housing and the one pound lighter rotors and
consequently lighter balance weights. The rest is pretty much the same.
Here is what I have in mind for a side mounted water pump.
Also what happens to the water pump if you run the engine low on water.
In the case of the RX8 this would destroy the entire front cover
because it has an integral water pump housing.
Paul Lamar
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