George

I also found that shape to be the most compact.  I assume that when the
slide is 99% close there is only a small eclipse (new moon) shape remaining
to allow it to idle?  Let me build a working prototype before I send you
some pictures. I am trying to make it as small as possible so I can hug the
engine. It can be motorized if desire.

Doug

Doug,
Yep! I must have done a thousand calculations only to prove that the half on
half moon cut was the most linier - mind you it's obvious when looking at
it. I also wanted to get a feel on how the needle should be shaped using
those calculations.

The small eclipse you speak of, I was going to increase that with a notch,
but decided against that as my calculations never got to the point of
estimating air flow and fuel flow at idle speeds. I decided to just make the
needle adjustable up and down as I had originally planned. The notch is
primarily for air feed to the idle jet ( which I don't have). The O2 monitor
and adjustable height needle ( turn on a thread to adjust) is the best
approach in my honest opinion. The low pressure adjustable regulator is a
good idea as well.

As I plan it I will have 3 modes of adjustment. One with the regulator, Two
with the inlet valve ( turn knob on thread- needle into seat). These two can
be the set-up adjustments and the third, a manual cockpit control to adjust
the needle up and down for lean and rich control. The O2 monitor will be my
primary reference tool.

I notice that some slide carbs have manual needle adjustments, i.e. take out
and reseat ( higher or lower), others have the same replacement needles (
rich and lean) and others turn the needle L or R for rich and lean. I
believe it can be done in one step by adjusting the needle up and down and
remotely ( only one needle required). From grinding the needle manually I
believe the one needle shape can be adjusted quite easily by hand. Many of
the commercially available needles can vary quite a bit  and can be
difficult to balance - unless your prepared to give the needle a bit of a
rib with wet and dry( apparently racers do this regularly). If your prepared
to do that you might as well make the needle from the onset.

I will look forward to seeing your developments.
George ( down under)


I don't know what you guys are smoking but I don't see how A is more compact
than B.

Paul Lamar ...No rotor no motor.

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