This is an interesting project.  I will be wanting the magnesium parts,
if available, to develop a light weight engine for LSA application.
Will limit cruise RPM to not go over the speed limit of this class.


George G    what are you planning for a PSRU?  I was hoping to talk to
Geared
Drives at AirVenture but missed him.  How about two 3 or 4 rotors into
the PSRU with one output?
I know a guy that will be wanting the HP you are developing for his
"ultimate" 4 seater, to be started in a few years.
Dan F

A six rotor engine is not going to work. The e-shaft is not strong
enough for six rotors. It has been tried. It will have severe torsional
oscillation problems.

Paul Lamar


What if you made the e-shaft from unobtainium?
Decker, Michael

The the six rotor would then be unobtainable :)


Paul Lamar


Dan, I talked with Bud Warren at sun-n-fun 2007 an he has a well designed
product with a prop governor and constant speed prop provision. Currently he
is adapting small block chevrolet V8 and V6 engines and the interface flange
is chevrolet. For my project having the prop center centered on the engine
is desireable and bud has about 7 inches as I recall offset. I am also
concerned about using spurr or even helical gears due to only one tooth of
the gear completely engaged aid  two more engaged but not necessairly
transmitting much of the torque.

I know that tractor trailer transmissions
use spurr gears with huge torque and shock loads but I just don't want to
fly a truck. I am however at ease with Tracy Crook's PSRU even though he
rates it at 300 HP. I will get around to doing the math on it  after I have
an engine but drag racers and monster trucks run large supercharged engines
through the same six pinnion  planetary gearset at up to 1600 HP. What I wll
mostly check out is the thrust bearing capacity and bending load from
P-factor at the front bearing on the axle shaft. I would compromise to a
ground adjustable prop wih no prop extension to reduce bending load, just
haven done the math yet.

As for the six rotor eccentric shaft I have some
thoughts on that also. Bruce Terrentine has a mazda aircraft engine shop
just south or raleigh nc 70 miles west of here. I talked this projec over
with him when I was thinking four rotor. He had no problem with connecting
two e-shafts end to end, an pointed out that they are 4340 steel. There is a
web sith on craigs rotary page for grannys speed shop which raced a  circle
track  modified and has dimensions for their home-made coupeling.  There is
a compan in austrailia making a one piece shaft with keyed in place
ecentrics on four of the rotors which I saw on a link on the pineapple
racing site. I am ill at ease with torsional problems on a long one piece
shaft and also the single thrust bearing with the potential for a lot of
thermal expansion by the time you get six rotors away.

The lemans engine had
a three piece but solid e-shaft. there was a center section with two
eccentrics at 180 degree rotation and slighty tapered ends. Each end had a
cosmo like  add on fpr one more rotor at each end with the drive end a
unique  part with the full diameter shaft a on a 13B and the connection end
of a 20B configuration. The end ecentrics were rotated 180 from the next
inboard rotor. there were no counterweights for the center  section rotors
and only one thrust bearing at the accessory end. The e-shaft had a tension
bolt  through all three pieces pulling the pieces on the tapers for a
friction drive although there is a small woodruff key for assembly
alignment.

I am using three RX8 e-shafts. the accessory end doesn't know the
other two engines are there. the coupeling to the second shaft is copied
from Tracy Crooks PSRU using the automatic transmission flywheel and
urethane isolation bushings. The adapter to the accessory end of the second
engine is a   one piece hub and plate withthe hub exending back to the
thrust bearing. The injection iol pump drive gear can be bored to fit over
the hub if I need it, but the stock oil pump is not used due to everything
coming from the moroso gearotor dry pump stack. The dry sump stages pick up
the centerhousing return oil sending it all through the coolers before
coming back to the tank which  can be the sealed space between the engines
if a smaller coupeling is used.

The e-shaft on the drive end engine has it's
accessory end built up by welding and turned down and ground to a size
slightly smaller than the e-shaft bearing.

A larger thrust bearing  3
stacked set is used to reduce RPM between the thrust bearing faces to 1/3
engine RPM between stages. The coupling is as described above. All the
e-shafts are torsionally isolated and two come out of the car engines ready
to use. There is a web address lost in my terabite sized hard drive for
someone who builds up e-shafts as described above but I don't have their
address, might be  in Australlia.


I am using an aluminum water pump
cartridge
from a 426 chrysler hemi a real nice piece for $39, high flow, cast
impeller. this drives off the accessory engine. The supercharger drive is
curretly to drive off the drive end engine but if I can get the exhaust
plumbing configured for clearance I would rather drive it off the accessory
engine. Taking 75 Hp off at that point reduces what the coupling to the
drive end engine has to transmit.

I am nearly done wih the p-port drawings
which are the same as the 8 port side port engine without the ports. When
completed for side ports there is a necessary 3/16" thick bulkhead in the
port passage just inside the port opening necessary to due the moulding for
the sand casting. This recess could be cleaned flat at the foundary to
cast an unported side housing and leave the rest of the port as cast to
reduce casting weight. I made good progress on the drawings yesterday and
hope to send some postings shortly in 3D of the parts. THey will need to
send one at a time due to file size. If I can't get them to send I will mail
a CD to Paul and  he can post  them  if ther is any interest.

george grimes