Sender: <marv@lancaironline.net> (Marvin Kaye)
To: flyrotary
Date: Wed, 23 Apr 2003 20:17:36 -0400
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Reply-To: <alventures@email.msn.com>
From: "Al Gietzen" <alventures@email.msn.com>
Subject: 20B dyno results
Organization: ALVentures
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For those of you not also on the "other" list;

>After much double checking, head scratching, and some further testing
we finally concluded that the only explanation could be that the timing
was actually very much early.  And the only way that could be true was
if the timing marks and the pointer did not relate to the position of
the rotors.  

 By viewing the position of the apex seal through the two sparkplug
holes, measuring angles, etc. we made a new TDC mark on the pulley, and
a new 20 Degree BTDC mark.  The original marks were about 15 degrees
off.  

We re-set the static timing on the crank angle sensor, and fired up.
Ran well, and disabling leading had a bigger effect than disabling
trialing, as one would expect.  To verify timing we put a pressure
transducer into the trailing plug hole, ran an oscilloscope trace
triggered by an inductor on the leading plug wire. A very small timing
adjustment (about 1.5 degrees) gave us the trace we wanted.
(Fortunately, the operators know what the right trace looks like based
on their prior 4- rotor engine development work).  We then ran up to
Tracy's recommended set point of 5000 rpm > 22" MAP (actually 24") and
found we were RIGHT on our new 20 degree mark.  Problem solved.

> Runs went fine after solving timing issue.  Don't want to publish 
> before data is complete, checked and analyzed; but right now I'm 
> pretty excited.  Torque curve very flat 2500 - 6000 at about 200 - 220

> ft--lb, hp about 255 at 6000; still going up in a straight line; so we

> are going to have to run to higher rpm.  Coolant flow 48 gpm @ 6000, 
> oil flow 15 gpm @6000.
> 
> Al

Thanks Al. Good info on the coolant flow and oil pump flow. Is that
through a rad and an oil cooler? I assume you have flow meters in the
systems. Whose dyno? Perhaps some of us would like to rent some
development work. 85 HP per rotor at 6000 RPM not bad. 
(two rotor equivalent 170 HP).

Paul;

Flow is through the engine and through the heat exchanger on the dyno.
Have data on pressure drop through the dyno heat exchangers.  I'll see
if they have any. Yes, we have flow meters in the system that read out
on the data channels.  At my insistence early on we plumbed in meters to
calibrate; turns out they had an incorrect scaling factor in the oil
flow readout giving too low a reading.  Correct data agrees exactly with
the one data point I got from Atkins a couple of years ago. 

I also plan on putting the thermostat back in and getting another flow
rate curve on a fully open thermostat.

85 hp per rotor is nothing to shout about, but is definitely good for an
unoptimized brief run to that rpm, with my tangential muffler and
secondary muffler, followed by the dyno system which includes another
muffler.  We will be doing runs with a straight pipe out of the
tangential muffler, and a bit more tweeking, so I'm going to guess we
can find another 10-15 horses.  This is also with the stock 20B rotors,
9.0-1 compression ratio.  

Based on data that Mazda generated on compression ratio, the difference
between 9.0 and 9.7 at 6000 is probably about 10 hp on this engine.  We
may get a some of that back on a bit more spark advance.  The
interesting thing is that the HP is still climbing in a straight line at
6000, so we will be testing to somewhere around 7000 rpm, a point where
the compression ratio difference is pretty much gone.

More testing planned for tomorrow evening.  I will eventually post
curves here, but be patient because my next month is fully booked,
including getting married and a week away from here.

The dyno facility belongs to GA Aeronautical systems, and is leased by
one of the owners, who I happen to know (that helps).  I think you met
his man, Scott Duffy, who was doing the all-aluminum 4-rotor development
program.  Scott is running these tests for me in his spare time.  The
4-rotor development is shelved at the moment, maybe for good.  I will
inquire of Scott about possible testing for others.

Al