> -----------------------------------
 > Paul,
 >
 > I thought we talked about a larger diameter, slower turning turbine some
 > time ago. This looks very good! I need one for around 5500 continuous
 > engine rpm.
 >
 > Steve Brazil
 >
 > ------------------------------------------------
 > I think we finally have a handle good enough to recommend a direct
drive turbine
 > diameter and blade configuration as a starting point.
 >
 > I'll run through the numbers for you. Such a low engine RPM may not
be practical
 > for a direct drive turbine. So don't get your hopes up too high.
 >
 > Paul Lamar

Steve:  In February of 2008 I suggested several, larger-diameter
turbines as a means to effectively turbo compound the Renesis engine with
its side-exhaust arrangement (see attached images).

Paul:

I bring up the multiple larger-diameter turbine idea again as a possible
solution to problems you stated in your post, namely:

 1. leakage around the ends of the blades.
 2. centrifugal loads on the blades
 3. metal loses it strength as the temperature of the metal increases.

Paul, your initial design makes all the stresses pass through one
turbine.  Might more than one turbine, for example, two turbines, each
receiving only half the stresses that the single turbine design would
receive.  Might that make it easier to tighten up clearances, reducing
leakage?  Since the blades only have to produce power from half the
amount of exhaust, might that not result in lighter blades, resulting
smaller centrifugal loads, and lessen the thermal loads on the blades?

Perhaps the two turbines could be placed one at each end of the engine,
attached to each end of the e-shaft?

I am not in love with my idea.  I am just trying to think out of the box
to have your idea succeed.

Les Nordman

Pretty good drawings.
It is a possibility as you would be dealing with half the total heat.
You need dual scrolls however as you need to distribute and focus
the exhaust gas  on all the blades simultaneously. The e-shaft torsional
frequency would be lowered and you might get into torsional resonance problems.
It would certainly work.

Paul Lamar