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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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