Hi Doug,
I am anticipating a problem feeding 40-50 HP into the front
e-shaft through a multi V belt system.
Depending on the size of the smaller pulley there will be a
significant side load due to belt tension on the e-shaft. There
are two manifestation of this. Bending loads in the e-shaft and side
loads on the front main bearing. This can be mitigated some what by
mounting the alternator on the opposite side of the engine.
The ultimate solution would be an auxiliary bearing and shaft inside of the
new e-shaft pulley with a flex coupling to the existing e-shaft alternator
and water pump pulley.
For more info see http://www.rotaryeng.net/beltpsr4.gif
Paul Lamar ...No rotor no motor.
Paul
Yea for initial testing I'll whip up something to capture the load.
For the final design I might bring the power in the other end as I
originally planned. The semi-automatic,flat RX-4 bell housing I have has a
nice side slot and a large 1" id bearing mounted in the center.
Doug in Japan
-----------------------------------------
Opss just thought of something that will put a kabosh in your plan
of feeding the turbine power into the rear of the engine.
The stock turbo charger compressor and hence the shaft you are going to
extract power from faces the FRONT side of the engine. Therefore the
Rotrex gear box needs to face the front side of the engine.
Other wise you will have to make a custom exhaust manifold and redo
the considerable oil and water plumbing for the turbo.
Which way does that Rotrex rotate looking at it from the compressor
wheel side? Clockwise or counter clock wise? I guess I can figure it
out by looking at the compressor wheel. OK that worked. It rotates
clockwise. Looking at the back side of the rotary it too rotates clockwise.
Now the question is will the Rotrex work feeding the torque
in from the compressor wheel while rotating the compressor wheel
clockwise. Normally the torque goes in the other end.
Ops again. Unfortunately the stock turbo looking at it from the back side of
the engine rotates counter clockwise. Darn!!!!
I guess you have no choice except to turn the turbo around, redo the plumbing
and build a custom exhaust manifold and feed the power into the back side of
the
engine. One advantage is the belt side load will have no affect on the e-shaft
or
main bearing.
I guess you knew that already. You are way ahead of me :)
Paul,
Yes you got it. I have to turn the turbocharger assembly around or stick
the turbocharger way back in (in my application) behind the traction box
near the front of the engine. I want to keep as much weight forward as
possible to counter act the heat exchangers behind the firewall so it looks
like a custom exhaust manifold is needed. I had counted on making one in
any case because I doubt I'll end up actually flying with the Mazda
turbocharger.
Yes its tricky. The problem is that the input and output shafts of the
ROTREX traction drive, rotate in OPPOSITE directions. The engineers told me
the traction drive will work equally well in either direction but actually
the nut and bolt holding the compressor and pulley on have been designed to
tighten under operation. This means the compressor side thread is reversed.
Naturally this is a good thing:)
I don't think the rear of the engine will be much more robust concerning
side loads than the front and I might need a plate sandwiched between the
bell housing and engine to support another shaft bearing. This same shaft
will insert into the engine e-shaft on one side and contain the PSRU sun
gear on the other side of the 5 inch thick bell housing.
Bill,
Yes I looked into a Prius type of transmission early on. I was concerned
about the weight, diameter, and complexity of such a transmission, isolating
the transient load the prop would place on the unit, and matching step down
ratios from the gear drive. Other than that its great design:) Presently I
plan to mount the ring gear with elastic bushings around the bolts. I am
aiming at achieving the effect that Tracy accomplishes with his input shaft
and dampening plate.
Now I am sketching a design that brings the turbo compound power in before
the planetary reduction mainly because the traction drive gives a power
reduction of 9.47 :1 and with an additional 1.7 or so pulley reduction, we
are very close to engine rpm.
A belt CVT is still possible for testing since the driven pulley on the
power shaft is under spring pressure only and can spin with the shaft. The
variator on the traction drive output side, contains the clutch and has a
mechanical governing mechanism. Some of the CVT units I have found have
round weights within the variator that slide outwards at higher rpms forcing
the variator plates together and thereby raising the rpms applied to the
driven pulley. This would allow us to create, within a narrow speed band,
a self adjusting torque converter by selecting different weights.
Personally I think the belt CVT is rather clunky and wouldn't want to fly
with it. Hopefully we can use Rotrex adjustable speed unit when is comes
out in the summer of 2006. This might be all we need and be very compact.
Clutch would be as simple as soft engage or not.
Doug in Japan
--------------------------------------------
Are you sure about that Rotrex opposite rotation? That would mean
they are taking power off the ring gear and not the planet carrier.
Double check by turning the input shaft and watching the compressor
wheel? Kind of hard to get a ten to one reduction taking
power off the ring gear.
Paul Lamar ...No rotor no motor.
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