Is there any reason why the particular gear ratio between the rotor and
the
output shaft (not sure if this is the proper term) was chosen?  Would
there
be a way to modify this so that the PSRU was essentially integrated into
the
motor?  So, for example, so that 4 turns of the rotor were necessary for
one
turn of the shaft instead of 2?

Just a thought, but might save alot of weight and one of the major risk
factors of auto conversions.

Thanks,
Brannon

I am not sure what you mean by "integrated".
Can you come up with a sketch?

Paul Lamar


Brannon, The PSRU ratio ideally is the engine RPM at max power for
take
off devided by the RPM where the prop tips are going supersonic. The
next
factor is that in our case we don't particularly want the added weight
of
offsetting the thrust line above the E-shaft center. The planetary gear
arrangement puts the output shaft directly in line with the e_shaft with
 the
added benefit of driving through 6 planet gears for a minimum of 6 teeth
transmitting the power rather than one tooth on a gear to gear drive.
There
is also a lot  of cumulative line contact on the gears with the
planetary,
therefore a relatively small gearset can be used. The gearset of choice
is
from Real World Solutions designed by Tracy Crook. This PSRU uses
a superduty ford diesel (E40D) low range planetary which happens to be
2.85
ratio  when the ring gear is held and the planetary drives the prop
Holding
the ring gear also turns the prop the same direction as the engine
rather
than reversing the rotation allowing a larger selection of props to
use..
Ideally  we could use more gearing in the range of 3.20 to 1 but to
use
mass produced gearsets we have to choose something commonly available.
In
my case (6 Rotor) I need a larger gearbox for 700 HP and after looking
at
photographs of planetary gearsets for sale on E-bay I chose the 4 wheel
drive transfer case planetary from the same superduty Ford F350
transmission. The ratio is 2.64 to one. More gear would be better,
however,
this gearset needs no machining off of extra parts  and is well
supported
with bearings. It is also 4 pounds heavier than the E40D but I  can't
compare the weight of something not strong enough with something that is
overkill. This planetary is only used when the 4-wheel drive is in low
lock
so even used there are very few hours of operation on the parts. I
bought
 my
set for $45 and it looks like new. I entered all the Ford parts in
Rhino4
last weekend and am designing the housing next weekend. I still don't
have
the shaft mounted oil pump that fits around the input shaft in the truck
which I will use for pressure lubrication after running the oil through
a
cooler. This will allow useing gear lube in the PSRU rather than engine
 oil.
I well attempt to attach a JPEG image of the Rhino4 drawing showing the
 Ford
parts and the thin wall prop shaft designed to use this gearset. All
drive
is thru splines including one that has to be cut near the end of the
propshaft The rest of the splines are used as is..The JPEG named
geartrane
shows the Ford parts which are used as they come out of the truck. The
JPEG
named PSRU componets includes the propshaft as well as the parts
assembled
for use. In both images there are two lineups of the parts showing the
view
from both ends.


george grimes


George,

I wonder what propeller you plan to use.  Avia?  In order to get 700hp
from a 6 rotor, it seems that you'll need to run the engine at upwards
of 6000 rpm (naturally aspirated).  That will make your prop RPM
around 2300+.  An engine of similar horsepower is the PW R1340.  Most
of those are direct drive - like mounted on the old T6 Texan (SNJ),
and are generally rated at 2200 RPM.  In that application, the two
bladed prop is terribly noisy at takeoff (full) RPM, certainly losing
some efficiency.  I understand that they are 108" diameter.  A 3
bladed prop of smaller diameter will help..  Being able to turn the
prop slower would be even better.


Regards,

Matt-

I would not put too much credence to a six rotor. The output shaft on
the last rotor is not getting any larger. My guess is 5 rotors is pushing
it.
Emon Hurley built one years ago.

Paul Lamar


Wow six rotors all lined up, thats a commendable effort.
And not cheap either, that box of apex seals look like it could
cover this months mortgage. Pauls right, that rear shaft will be
taking a hammering. The output may prove to be OK, but the
coupling with the next shaft will see 4 rotors of torque loadings.
Ultimately it will come down to how strong the couplings are,
and with a bolt that long to join them, I wouldnt bet my house on its
chances of survival. I'm assuming that there are 4 main bearings,
and that the middle 4 rotors are using their neighbours for
counterweighting. Have you flow tested the end secondary sized
intakes to balance their airflow with the rest of the primary type intakes?

No front mounting for that engine, it'll need a solid type mount
or two even, 1 around the centre, 1 at the rear. Those old style end plates
have very little meat around the dowels. If you use after market full length
dowels, and they are larger O.D. than standard, then there will be even less
meat there. (can you get dowels and engine bolts that long?) Mazda
beefed up the endplates in this area you may have noticed from the series
4 engine onward, even for the N/A engine. Also why they changed to rear

It would be good to hear you have success with this engine, failure will be
very expensive.  Full length engine dowels/ bolts is a must for this block.
Vibrations and long engine bolts are already a problem with two rotor
engines.  I'd also recommend bolting a 1 inch thick aluminium plate to the
base of the engine between it and the sump, this will add to the blocks
torsional rigidity and sadly the overall weight.  A few strategic holes, and
it makes a great oil baffle pan too.


By the way what a lovely looking set of headers.
Good luck mate

Sam Watson