Here is a some rare and interesting data on the fuel consumption
characteristics of a Mazda rotary at partial power. Something I have never
seen on a Mazda rotary engine before. I think Tracy will find this
interesting as it confirms the research he is doing by leaning
the 13B at altitude and partial power. This is a mild street
ported EFI Mazda four rotor engine. Note the numbers are
under .45 pounds of fuel burned per HP per hour at 5000 RPM.
This is a conventional peripheral exhaust port so the RX8
version should do even better with side exhaust ports.
The intake manifold is nothing special and not particularly
well optimized IMHO. More pictures on the engine shortly.

I am indebted to Scott Duffy VP of Spectrum Power for sharing this
with me. It is from some dyno runs on an all aluminum four
rotor Mazda aircraft engine engine Scott designed using stock
Mazda 13B rotor housing. More on the aluminum end housings
later. I am working on Spectrum to offer them for our use.

Paul Lamar

Amazing!   That data correlates almost exactly with what I'm seeing in the
airplane.  I get a look of disbelief from most people when I mention mixture
ratios of 20 : 1  and .46 - .47 BSFC but that is where I typically run at
cruise.   This is off the bottom of the scale on my Air/Fuel mixture monitor
where a piston engine would normally not run at all.  I think this supports
the 'centrifugal stratified charge' theory and I'm surprise this has not
been mentioned (as far as I know) by Mazda or any SAE papers.

The peak efficiency around 5000 rpm also correlates with what I see, another
reason for targeting this rpm range for cruise conditions.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

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