Al Gietzen wrote:
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
That straight line HP function is typical for the rotary and is
why I have been pushing for the 2.85 gear box all these years :)
Ironically an aircraft engine also has a straight line HP function
from 2700 up to about 3600 RPM or so. That means the red line is there
for the life of the engine and the breathing is way more than
adequate at 2700 RPM. Same goes for the rotary at 6000 RPM but but
the life is way less affected by RPMs up to say 7500 RPM.
Yes I know Scott. Our man Jeff Spitzer also works for GA Aeronautical systems.
Rotor heads all at that company including the Pres. :)
I am surprised you have enough pull to get in there. You must
own a lot of stock :)
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.