This trick will roughly  double the flow signal
for a diaphragm type carb. It is similar to Dial A Jet.

Dynamic pressure is applied to the back side of
the diaphragm. It works in conjunction to the vacuum in the
venturi to increase the fuel flow all other things being equal.
If you made the venturi shallower it would add to the HP as there
would be less of an air pressure drop across the venturi.

If you made the main jet smaller to maintain the same
flow the fuel mist would be finer. Sort of a low pressure
fuel injection effect.

For an accelerator pump version you route the dynamic pressure
to the air pump on the throttle knob.

The dynamic pressure here is that pressure measured in the pito tube in the intake
runner the velocity of which which can be up to .4 mach. The actual intake velocity
is strictly a function of how much air the engine is using. This is not the
forward velocity of the airplane. It is the velocity of the air going into
the engine through the intake runners.

This scheme gives a very powerful signal as dynamic
pressure is proportional to velocity squared. The carb can also be leaned
using this scheme as a needle valve can be inserted into the line from the pito tube
to the pump knob on the throttle and thence to the back side of the diaphragm.
Also merely twisting this tube can change the amount of dynamic pressure
recovered.

There is a version of this on the Ellison carb. Here is a picture of that.

It cost a few cents for hose and a brass tube.

I owe this entire thread to Aubrey for suggesting a diaphragm carb to begin with.
Sure is simple and cheap to make.

As soon as a sort out the parts needed I will upload the 3D drawings.

Paul Lamar ...No rotor no motor.

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