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