Doug in Japan::
 Hope all is well

 I notice Rotrex has a new small compressor that apparently spins our
 direction up to 240Krpm. I hav'nt seen enough postings here regarding
 traction drive compounding so I am not sure of some of the critical
 details like the relative size of the turbo conjoined to size 'X'
Rotrex

 I did some business with a local turbo rebuilder recently who talked
 about left hand and right hand turbin scrolls. I hav'nt looked yet; my
 guess is, there will likely be something that could be retrofitted to
 the inlet side of a Rotrex.

 I am considering modifying an Aerocharger for this purpose; if,
 Aerocharger does not make a right hand turbin scroll setup.

 Ed Carver

 There is a bunch of stuff
 at http://www.rotaryeng.net/turbo-compound.html

 Also here are some pictures of the rotrex.


 Paul Lamar


Ed,

The designer of the Rotrex traction drive told me it would work in
either direction, however the oil pump ports,  the drive shaft
thread, and drive plate thread need to be reverse to turn CCW.  I
haven't played with the little one you mentioned  but I think it is
for motorcycles.  The 13:1 ratio  30's series can handle up to about
30 hps.  The 7:1 ratio 35's series up to 70hp. Turbo compound
devices  increases the torque to the shaft and the final drive
pulley can get large or the traction drive outlet very small.
 Matching a turbine to the traction drive is no easy trick.  The
best way may be to have an axial turbine constructed by some of the
small jet engine hobbyists.  Jet Beetle comes to mind.

Concept viability can be tested using a radial turbine however.
Doug in Japan


 Reversing the rotation means both sides get reversed. If that is true,
 then we must use a right hand scroll turbine because our engines spin to
 the right, the rotrex drive to the right, and the rotrex compressor to
 the right (veiwed from their respective ends. So even the small one will
 not solve our problem if using a left hand turbine.

 The only belt drive I know of that will reverse the rotrex pulley,
 thereby facilitating our right hand drive engine and a right hand drive
 turbine, is a timing belt with cogs on both sides and an idler pully
 placed furthest from the crank used as the tensioner.

 I believe you are suggesting that if we use a max turbine speed of
 80krpm, then the compressor side of the rotrex should also be turning
 the same speed at our desired engine speed. This means that both the
 turbine and the rotrex outlet shaft should each have an equivalent
 linear rotation speed up to our desired redline.

 I suppose before the engine comes up to power, the turbine is being
 driven by the rotrex until at some point the exhaust begins pushing the
 turbine and power recovery begins.

 I think it is time to look hard for a suitable right hand turbine with a
 sweet spot on the turbine map at around 80krpm. I guess that is where
 you left us before Doug. Just making sure I'm part of the way caught
 with ya.

 Ed Carver

 This device works with most turbo's. You don't need reverse
 rotation.

 Paul Lamar



Paul, Pardon my lack of knowledge but what is a "traction drive", I
haven't heard of one before, and looking at your photos I still cannot
see how it works,:'( . The gears with teeth are OK just the other bits
w/out teeth has got me.
  John Burey.

Gears have RPM limits so traction or friction drive is used for extremely
high RPM. 50,000 and above.
http://www.uspto.gov/web/patents/classification/uspc476/defs476.htm

Same as the steel wheel of a locomotive on a steel rail.

McCulloch AKA Paxton used planetary drive steel balls.

Several auto transmission on the market use the principle as does
a zillion motor scooters in Europe.


Paul Lamar


Hi  Paul, Thanks for those pictures, I still am at a loss, with the
Paxton ball drive the picture looks to have a variable flange pulley for
a belt, but does it have each flange running opposite directions? and
then one can move the driven (or drive) in and out to get the speed one
requires? I would have thought the friction would chew up the drive.
 Thanks  John Burey.

I am not sure the two pictures are of the same device.

Paul Lamar