Paul,
I'm starting to model a rotary in my spare time, and I am in need of
some accurate dimensions for the 13B and/or RENESIS engine. I've
drawn the trochoidal housing and rotor shapes from Yamamoto's
equations and numbers published in his book, but I don't have an
example around that I can measure for the other dimensions.
What I need mostly at this point are critical dimensions like rotor
housing depth, center housing depth, thickness of the rotor housing
wear surfaces, locations/spacing of the tension bolt holes, major
e-shaft dimensions, stationary gear height and diameters, and so
on...
My purpose is to design new housings and possibly rotors that can be
used with the mazda e-shaft, gears, bearings, etc.
I've seen pictures of your models... are they detailed to this level,
or are they mostly just for mock up?
Josh
I have a iges of a rotor housing. Can your email handle a zip file?
Paul Lamar
Yes, zip is just fine.
Josh
Here it is.
Paul Lamar
Hi Josh
I have extensive V5 background with aero design and have thought
about doing something similar. Will your final models be for your
use only or is their some possibility for sharing? Just don't want
to duplicate the effort. Will exterior surfaces and interfaces be
accurately modeled? (plus/minus .030)
Creating new housings (please make some RB aluminum housings for
half price...I will be happy to buy) is interesting but my current
main goal would be to create a firewall forward DMU (digital mock up)
for EBU (Engine Build Up) purposes. The aircraft will be an RV7A
(have it but it is still in the crates). Once this is created and
appropriately parametrized I can run thru multiple scenarios of
different EBU configurations as well as get some idea of engine
location vs weight/balance impact which would aid in mount design
etc...
Thanks,
Kent Baxter Contract Design engineer (Aerospace) presently OTR (on
the road)
Kent,
It wasn't my intention to duplicate Mazda housings, but to create
models for new parts that will work with other Mazda parts. If we
can come up with something to compete with the RB housings, that'd
be great. I also intend to attempt a design of some rotor housings,
possibly with replaceable friction surfaces, but I haven't really
thought into it too much. I'm more than happy to share what I come
up with with a sort of honor system license... If you sell anything
based on what you get from me, throw something my way.
I was also a contract engineer until recently. I went direct with
the company I was contracting through for GE. My work has mostly
been in Wichita and Middle River, MD. I'm currently back in
Wichita.
Josh
Josh, Did you get the zipped IGES of the rotor housing I sent?
BTW do you or anybody else on here know anything about the HP
capability of J section belts at 6000 RPM?
Paul Lamar
Paul, It depends on the number of ribs of course, but Gates has
charts for them. Go ti the Gates web site and search Micro-V. J
section is fairly small. K might be better for power transmission.
Bill Jepson
I did but I found no engineering manual. They wanted me to contact
them and they wanted a bunch of info. If you have a pdf please email
it.
The only thing I could download was this chart. I want to operate in
the red box so I know I need a J section. What about pulley diameters
for that range?
Paul Lamar
Josh, I have modeled in Rhino 3Dm format the rotor housings and
endplates with
appropriate aircraft modifications. The modifications include
parallel cooling,
additional external tension bolts, a larger water pump, dry sump
oiling system,
reworked intake ports (8 port) with stock renesis exhaust, A 3 inch
bellhousing
flange extension to space Jeff's CNC plate and also a front housing
with a
bellhousing connector to stack 2 or 3 rotor engines. The housings are
2 piece
sandwiches so no casting cores are needed. Everything is "O" ring
sealed. Material
specified is 398 aluminum alloy with 17 percent silicon carbide
nodules which are
the wear surface. There are motor mount ears (or not) for front,
middle, or rear
mounting although I will mount from the PSRU plate. THESE HOUSINGS
ARE
NOT 1/2 THE WEIGHT OF THE STOCK IRON HOUSINGS. ALUMINUM IS 1/3
THE WEIGHT OF IRON BUT ONLY HALF THE STRENGTH. Therefore I used a
little more
material even with the higher hot strength of the 398 alloy.
There is a 3
rotor intermediate
housing in the drawings, also 2 piece and 8 port although P-port
is also
useable. At persent
I have CNC routered all the patterns and done 1/2 the touch up
sanding but
don't know
what to seal MDF patterns with for the foundry?????? I also have
drawings
of the
housings in machined condition with the machining allowance cut
and "O"
ring grooves.
I can send attachments in yahoo mail a few at a time of the 3Dm
files if
it would
help in your project. My yahoo mail is george_grimes7 at
yahoo dot
com.
A few suggestions would be to remember the stock
housings are
cored (hollow)
and you could do the same, however a two piece sandwich allows CNC
machining
directly or casting from patterns. Also you can opt for an iron
wear face
inset in the aluminum
housing which would give access to machine out material behind
the wear
surface.
The thing is that there are a lot of things to keep separated.
Coolant
water that
is ported thru the rotor housings and cools the end housing
combustion side
faces
and oil in and out for lubrication and rotor cooling and also
cooling on
the center housing.
Then there is combustion air and fuel (if side ported) and
exhaust gasses
if using
the renesis exhaust. Water cooling around the exhaust ports and
sealing the
water around the tension bolts as well as oil through the hollow
dowels for
the
stationary gear bearings. Most of the oil exits thru the center
housing but
some
from the front housing accesory case has to get to the pan. The
rotors
basically
sit on the E-shaft journal bearing located longitudinally only
by the side
seals
running in the side housings. Therefore additional oil needs to
be plumbed
into
the lower surface of the drive end rotor for a verticle
installation in a
helicopter.
After trying several other arrangements I am of the opinion that
only the
Mazda
layout is really workable. The engine as it comes is durable and
the only
reason
to change it is to get some weight out of it. And once you commit
to that
there
is no reason not to increase cooling capacity and tension bolt
strength. My
goal was to build a 4 to 6 rotor which would be difficult with
the stock
accesory end
side plate. There is no reasonable flat area to bolt to,
particularly at
the
tension bolt locations, and the tensiobn bolts are threaded into the
housing at the
accessory end. This project seemed simple at the outset but
spiraled out of
control in short order. One other suggestion. I added 3 tabs to the
patterns so that
I can mount the castings in my lathe and face them off and do
the boring of
the stationary gears without removing the part from the lathe.
The second
side
gets faced mounted in an adapter fit into the finish bored
stationary gear
mount.
That leaves the interhousing "O" ring groove and bolt holes to
drill and
reem.
Seems simple but I haven't done that part yet.
george grimes
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