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Thanks Richard, I didn't realize it was a slide
carbie, however what about the 38mm carbie. I'm trying to understand why you
couldn't get the full range with that carb and felt it may be a restriction like
a venturi.
I can see why a larger carbie feeding a smaller (
38mm) runner would be the best mix for best velocity.
George ( down under)
----- Original Message -----
Sent: Wednesday, June 23, 2010 3:42
AM
Subject: [FlyRotary] Re: Peripheral Port
13B Rotary Engine
The Mikuni VM series, as most any slide
throttle carbs do not have a venture throat. The throat size changes with
the slide setting. Mixture is maintained with different components at
different slide opening. These are, idle jet-needle with jet-main jet. Also,
the shape of the slide opening is contributing to throttle
response.
See Mikuni web sites for details.
Complicated function with simple
mechanics.
Richard Sohn
N2071U
----- Original Message -----
Sent: Tuesday, June 22, 2010 4:00
AM
Subject: [FlyRotary] Re: Peripheral
Port 13B Rotary Engine
Thanks Richard,
That's interesting! Did you have a choke or
reduction in throat size in the 38mm carbie, and does the Mikuni have a
venturi throat
George (down under)
George,
I had focused on the 38mm and was doing
pretty good with it, until I realized I could not maintain a good mixture
over the whole operating range. Obviously, that is why the specification
says it is good for up to 65hp.
Even so the
carb is 44mm now, my intake runner is still 38mm maintaining the intake
tuning.
Richard Sohn
N2071U
----- Original Message -----
Sent: Monday, June 21, 2010 4:59
PM
Subject: [FlyRotary] Re: Peripheral
Port 13B Rotary Engine
Richard,
Ah The magic 44mm. I know you are
running a 12A but at what rpm are you running out of breathing,
provided you have had the single that high. I would have to run
the numbers but thought you would get away with a 38/40mm carb and
push up the velocity.
George (down under),
this flywheel is my design, it is steel
with the cut outs for balancing. The steel section is 14mm thick, and
the ring gear is 250mm diameter, coming off a Metro Geo engine.
I calculated my hp from fuel flow using a
BFSC of .5 . May be a little optimistic. Mixture was slightly rich at
the tests.
I am running now a Mikuni VM44
carb.
Richard Sohn
N2071U
----- Original Message -----
Sent: Monday, June 21, 2010
3:39 AM
Subject: [FlyRotary] Re:
Peripheral Port 13B Rotary Engine
Richard,
We seem to be singing from the same
sheet of music in regard to projected HP at RPM, at optimum
performance. So what weight have you got on that flywheel, it seems
to be a cut down manual cast flywheel from a past photo. I figured I
might need a heavier flywheel than the flexplate and was considering
having one of those aftermarket steel ones made and have mounting
holes included to suite what ever damper I incorporate.
BTW this is single rotor specific if
anyone was confused.
George (down under)
Is anyone
flying with a Mazda 13B peripheral port engine? If so, how is it
working? Can you
describe the advantages and
disadvantages?
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