Ok. Let's shelve diesel wankel. Turbo compound rotary should achieve
the same specific fuel consumption. How do we go about making a big
turbine for the hot recover section?. Who could we hire to make this
item without charging an Aerospace prize? Could this turbine be the
flywheel itself? Thanks.

leman wings

http://www.barber-nichols.com/

Paul Lamar ......In NZ

Pratt and Whitney's PT6 is 50 years old this year, there was an
article in the AOPA about it. I recently completed my A&P, and the
DME had 3 old PT6s there for the test and for parts. The point is
that I dont think we need to reinvent the wheel. There are many many
small sized turbines that parts like the power turbine can be removed
from for testing. These are designed for the high temps and high
rotational speeds. I think maybe a turbine can be attached to either
the flywheel or the front end and eliminate much of the weight and
parts and pieces of the first generation TC. Just like Paul did for
TC 1.0 with the DD TC parts, an already produced part would keep
costs down.

As far as a diesel rotary, if the TC gets the BSFC down, the only
real benefit to a diesel rotary would be the ability to burn jet fuel
in parts of the world where avgas is not readily available.

As it relates to the low compression ratio, the older 2 stroke
detroit diesels had relatively low compression, and the answer was a
roots type blower.

Kevin Alderman


Hi Paul. Have you priced what it would cost for barber-nichols to
make your turbine? PT-6 turbine may be too small in diameter for the
job. Plus the design is for a lot higher flow mass then what a 13b
could put out. Thanks.

Leman Wings


If you want to go 3 rotor you can get a DD15 turbine and gear box
for $3000. You would have to cut away some of the cast iron and
replace it with SS sheet to reduce the 100 pound weight.

Paul Lamar

Hey Paul,

Why the intentional misalignment between the TC gearbox output and
the engine input?  Flex couplings and universal joints should only be
used to compensate for minor misalignment that could not be
eliminated by careful alignment of the two shafts.  The offset in the
drive will create unwanted harmonic vibrations that may damage the TC
gearbox. The universal will also get quite a workout at 5000 RPM.
I'll bet it fails about ten hours into the test.

Mark LaPierre

It is not a perfect world :) What happens when different parts expand
at different rates due to temperature differences?

Paul Lamar


What happens is a minor misalignment between two shafts that were
originally quite close to parallel.  That's significantly different from
starting off with a significant intentional misalignment.

I've seen failures of couplings between two shafts at much lower RPM
with far less power transferred on electric motor driven centrifugal
pumps.  I suppose this being just a test rig it's not all that
important.  If it fails no loss of life or limb will ensue.  You'll just
have to replace it before continuing the test.

 Mark LaPierre

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