While designing this carb I needed to know what to expect
in terms of fuel flow and mixture as I changed the pressure
inside the fuel chamber. This is the pressure difference across
one main jet. Some is due to lower than atmospheric  pressure in the venturi
and some is due to the higher than atmospheric pressure in front of the
diaphragm.
It is the difference between these two that flows the fuel.

I was amazed that such low pressure difference
of .5 psi can change the flow so drastically.
This is  based on a formula that Kinsler had in their
catalog and a chart of water flow for different
size main jets. The jet size chosen here for starting
purposes is .079 inches in diameter. The rotary will run
up to a mixture ratio of 17:1.

New flow = old flow times the square root of new pressure divided by old
pressure.


Here is the data, the program and the flow charts it was based on.
Check my math.

All of this is ground adjustable in my design including the main jet area
for each rotor.

The spring force on the diaphragm will initially cause the pressure
in the fuel chamber to be in the range of 2 psi. The fuel pump pressure
will be higher than that of course or you would not be able to fill
the carb with fuel. As the spring force is reduced by a manually controlled
cam the pressure in the fuel chamber will lower leaning the mixture. This
is very similar to the way Dial A Jet works.

This should be a relatively low cost, very effective
and very reliable carburetor with so few parts of any kind.

Paul Lamar ...No rotor no motor.


Paul,
Just remember these numbers will only be accurate with the kinsler pills.
The inlet radius, surface finish, hole size tolerance and exit shape all
effect these numbers. That's why I never mix manufacturer's jets when tuning
a carb.
Larry

Thanks Larry. Yes absolutely true. In fact this is water and not gasoline.
I am just looking for ball park numbers here so I get the diameter
of my jets and diaphragm spring forces roughly correct. The manual adjustments
will take care of the differences. I am now working on getting a handle on the
venturi pressure signals across the RPM range. I'll then add the various
pressure to get a rough overall pressure drop across the main jets
over the entire RPM range.

I got the SS tube for the RX8 p-port intakes yesterday so I hope
to have the rotor housings done next week. I'll then take them down to Mazdatrix
so they can rebuild the RX8 engine. I'll need that cracked RX8 front housing
back around then. Please ship it directly to Mazdatrix. Then if you can find
time to build this carb we can run it on the bench with no load and work out
the starting and idle issue before we get it on the dyno. The 58 Webber will
be a fall back solution if this thing don't work. If it does work it will cut
a couple of thousand off the cost of a Mazda aircraft installation.