Looks Good, Richard.
My experience was that at least up to the
6000-6500 rpm range that my engines produced more power with a longer runner
than a shorter one. I’m certain at some point up the rpm curve at higher
intake velocities that the curve would cross over to favor the shorter runner.
My calculations and experience (for the two rotor) indicates a PORT to Throttle
body length of around 22-26” was optimum up to around 6000 rpm depending
in part on your intake porting. So 24” sounds good to me.
Just for your info I idle my two rotor at
around 2000 rpm.
Ed
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Richard Sohn
Sent: Wednesday, November 05, 2008
9:40 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] single rotor
performance
Another step in the right direction.
In deciding which way to go with the intake for the single
rotor, I ran two tests. The first one with a short 8" long intake runner,
and a second one with a 24" runner.
The results are certainly not surprising, however, I had to
check the possible impact on idle characteristic.
Except for a different idle mixture setting, I was not able
to detect a difference in idle characteristics at 2000RPM. There is no need for
lower idle with a 3.33 : 1 gear ratio. If for any reason I want to go lower
with idle, I would have to increase the fly wheel inertia. With no load on the
engine it idles down to 1300RPM with the 8" runner.
The long runner also resulted in a 1" higher MAP over
the short runner.
The 24" runner as shown in the picture will in the
final configuration be at least 3" longer, because the carb has to com
lower than it is now.
The engine config is 12A rotor and housing using 1 1/2"
p-port.
The HP calculation is based on a bsfc of .5 . This is
probably conservative with EGT at 1700F and mixture ratio at 14.6 .
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