Douglas Fir wrote:

Hi Paul and everyone,

I just returned from Hiroshima and the trip was a wee bit of an eye
opener.
What follows are just a few of the points discussed.

I spent most of my time with the F.C. design office which specializes
in
electronic fuel injection systems, both control and injector design.
Their
main business is catering to recip. engines though.

Mr. Nakane just captured the world record (Guinness) best fuel
mileage for
the second year in a row and Mr. Kagawa designed the fuel system for
the 4
rotor winning LeMans' engine. Both have extensive design and test
data on
rotary and recip. engines both in building and in dyno time. Both are
ex-MAZDA engineers who thought they could "do better work" on their
own.

We spoke about the concept of turbo compounding the rotary as a way of
improving fuel performance and they said that it will be tricky with
only
one turbine and its other gearing, and  were of the opinion that it
wouldn't
have a chance with MAZDA MOTORS accepting it in their  automobiles.
They
weren't very  positive about MAZDA's rotary engine and remarked that
the sub
systems and controls had gotten very complex and as such reliability
suffered.  They remarked that Mazda's had every reason to be nervous
about
their rotaries flying in aircraft. They were both thinking that we
homebuilt
aircraft people just stuck in the automobile engine 'as is' and go off
flying.  This seems to be a common misconception by all people who
hear the
words 'flying with an auto engine'.

It was at this point I  gave them a brief review of how  rotary
powered
aircraft used a highly modified engine that has evolved over the last
5
years with the help of a talented international group of individuals
that
have networked to improve the reliability of the engine. I remarked
that
except for the block and a few perhiehals, the engine was an totally
different animal.  They were happy to hear that one individual Tracy
Crook
has succeeded in flying so many hours with the 13B, but were
concerned he
had changed to a RENESIS engine.   Interestly enough their
professional
opinion was that the 13B is far more superior than either Renesis
engine.
Remember though until I spoke with them they were thinking auto with
all of
its mufflers, and smog burners attached. They said the 13B does breath
easier.

They stated that the RENESIS engine configuration  simplifies the fix
of low
rpm rough idling problems, and as we all know  improves the low end
torque.
They said that it was common for all Japanese auto companies to
overstate
the performance numbers (with the blessings of the government) and
that only
the German automakers gave accurate data. They were VERY skeptical
about the
RENESIS engine improved fuel mileage claims.

Remember many of their friends still work at MAZDA as part of the
Renesis
development team so they get an good idea of what is being reported.
Perhaps like Paul says the zoomers are very lead footed. Mr. Nakane
said for
turbo applications the exhaust P-port is superior to the the high
drag and
heat absorbing side port RENESIS. In addition he stated the long
combustion
chamber of the rotary and its heat losses to the housing is one
reason the
fuel BSFC won't ever match the recip.'s engine.

Also Nakane   said that after 2000 rpms the 13B's fuel mileage
increases
when some of the exhaust gas is recycled into the next intake charge.
 He
also mentioned that the better turbo charger is the one that diverts
the
exhaust gas into two streams and enters the turbo from the  front and
back.
I may have misinterpreted this last bit of information though.

Both guys were a wealth of information but they didn't know
everything,
especially pertaining to aircraft applications.  To the elder Mr.
Kawagawa's
credit, he wanted to know more about the use of rotaries in airplanes
and
asked for me to send him  some pictures of installations and the
flying
video. He asked 3 times which is pretty standard way of saying over
here, "I
am really serious about this request" I will try to make him up a CD
of
different planes and designs.

His eyes lit up as I explained to him that yes I realized the rotary
seals
are easy to break in high boost situations but I would only want to
use high
boost for short time intervals when maximum climb power is needed and
then
only enough to 'normalize' the engine at higher altitudes and use the
excess
exhaust energy to run the turbo compound system.  He seemed to
understand
and grasp the advantageous immediately as I told him that airplanes
fly long
distances with few power setting changes. He seem to knows about
common
aircraft engine designs. He mentioned at an aside that most turbo
compound
applications had advantageous in the larger engines. Mr. Kagawa did
say 4300
rpms continuous were not a problem with the rotary. I didn't ask the
upper
continuous rpm. setting but suspected he wouldn't agree with the 6000
number.  I expect that Tracy has the most data on those ranges.

 As the younger Mr. Nakane remarked,  "Mr. Kagawa has more graphs and
information in his head then any sophisticated smart computer program
you
could every create for the dyno testing."  He also said that "with Mr.
Kagawa understanding of the rotary engine, he could probably
accomplish in
one month of dyno testing what would take another professional two
years to
do." They lead me to believe he knew enough about the idiosyncrasies
of the
rotary engine that he could  pinpoint some good working ranges for
our turbo
compounding application.  I got some hand written graphs on BSCF
research
they did with the 13B and I will try to get it into a useable format
to
post.

 They did agree that the two turbine set-up discussed earlier on this
list
was the safest way to test the turbo compound method. He advised me
to make
or modify  a cast iron  manifold with inconel butterfly valves and
not to
link the two valves together but have some sort of safety system so
they
could not both close at the same time.  Both have witnessed many
rotaries
detonate, and the chain reaction of several different components
failing.
When I get more details I will post them, but I think we all know that
highly pressurized fuel spraying on a hot exhaust manifold is not a
good
thing. Water and oil hoses coming off on test rigs were also
mentioned.

So it seems we have some advise and information to give to them as
well:)
They need to put the fuel rail on the cool side and double clamp
silicon
hoses with a quality spring loaded clamps.  I'll have to mention about
testing the coolant for high level TDS (Total Dissolved Solids) as
well.
After I explained I wanted to build my own dyno, they warned me to
seek
professional help. I took it to mean an offer for helping to test the
engine, but perhaps they were questioning my sanity as I was naive
enough to
think I could put in on the test stand for a few hours walk away and
have
the computer run the experiment:)  They both said that in their
experience
they sit and watch the engine and computer monitors like hawks. They
said
there are to many variables that despite our best efforts could fail
and
destroy the engine.

Other news:

K.C. Design is presently developing a small rotary engine for RC model
airplanes, they just purchased a small Wren jet turbine to play with
to
improve the fuel burn no doubt, and they have their own RC model
airplane
dyno test software ready to ship with a small eddy current device to
load
the engine for testing.  They recommended eddy current device as
being much
more stable for maintaining  constant rpms. They poo pooed the idea
of a
water pump with a dyno for accurate work. I am not informed enough on
either
approach to comment. I would appreciate anyone's' thoughts.

The more I think about it, Tracy, Paul, and Jim M. got it correct. I
should
use a prop to load the engine. I will need to borrow a two blade
constant
speed prop (able to handle 200 hp) for an year for testing if anyone
can
steer me in the right direction.

I just got my information package from the  Land and Seas dynamometer
company. Very nice and professional info. package. They sell just the
software if you are interested. They have an interesting concept that
I am
considering to put on my plane. Imagine if you could always monitor
the
torque that is going to the prop shaft.  With a small inline
transducer
(circular strain gauge) you can. Then by feeding this data along with
the
rpm and other temperature and pressure inputs into a  laptop running
the
dyno-Max software you have an system that logs data and conditions
every
time you fly. BSFC, fuel flow, and other data is available in real
time as
well as being saved for later review in less stressful times.  If
Windows
was more robust I would even be tempted to use this system as an
engine
monitoring system. Wonder if we can get them to port it to  Linux OS?

Down load your free software demo kit here:  www.land-and-sea.com

Doug in Japan.

Most engineers working for the automotive companies have a limited
view of
or control over  the  big picture. It takes a technically well
educated CEO
with imagination and vision to lead a company to greatness.

IMHO the efficiency of the ICE must be improved as the price of fuel
in the world goes higher and higher. ICE 30% fuel efficiency is not
acceptable in the
long term. Power plants using bottoming cycle (recovering energy from
the
waste heat in the exhaust) gas turbines are achieving
50% over all efficiency. Not practical however for moving vehicles. The
turbo compound technology is the only technology on the radar that will
result in an immediate 20% improvement in fuel efficiency with little
increase in size, cost or weight. The significance of this in the world
wide energy consumption scenario cannot be overstated.  Any minor
technical
problems turbo compounding may have will pale into insignificance in
the light of
these facts. IMHO turbo compounding is inevitable sooner or later.
It just takes a automotive company CEO with the vision and
understanding of
the technical issues to accept this.

BTW Doug did you get a tour through the rotary engine plant? If so
what do
you think?

Paul Lamar

Fascinating report.   I also think that the 13B is superior to the
Renesis for aircraft. The thing about the very hot peripheral exhaust
is that it is taking  heat away.  The side port has to be experiencing
a certain amount of heat soak.  Too bad the word is out now.  I was
hoping to pick up some nice 13b's  cheap, as people jumped on the
Renesis band wagon.   Jerry

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