Paul Lamar wrote:
This one truly does it all. combination throttle body, plenum,
alt air valve and ram air valve. it is about six inches in diameter
and with a bit of tweaking I might be able to get it down to
five inches in diameter and still have a 3 inch ram air port and
three inch throttle body.
This is a classic sleeve valve. The inner sleeve rotates and is
controlled by cables and a wheel on the instrument panel. This
one wheel controls the throttle and the alt air selector.
Ram air comes in from the top. Alt air comes in from the side.
The ends are capped of course and this is designed to work with
side ports and four or more runners. Best place for throttles
in P-ports are close to the block. Not applicable to P-ports.
Nothing that can do all these functions will be simpler or
lighter in weight than this. Easy and cheap to make in the bargain.
Here is the five inch version. Really tricky. The break through was
five throttles instead of only one when in the alt air position.
Don't ask.
The inner sleeve starts out closed with the three inch hole pointing
straight down. Rotate it clockwise 90 degrees and you are wide open
throttle on alt air. Rotate it another 90 degrees and you are wide
open throttle on ram air. To close the throttle rotate it 180
degrees counter clockwise.
Even easier to do if you don't need alt air.
Is anybody interested in this other than me? I am thinking of
having a pattern made and a bunch cast up. Next iteration will
be 4.5 inches in diameter and will have injector holders. At
wide open throttle this is superior to a butterfly and as good
as a slide throttle.
Casting seems the only practical way of making it but a composite
mold is not out of the question.
Hold on a minute there, mister.
OK, first, let's make certain I understand: you're using this rotary
valve as both the air source selector *and* the engine throttle,
correct? (If not, then the remainder of this post is perhaps moot.)
I like the way it automatically goes from off, to filtered, to ram air,
and back. It "automatically" uses filtered air when the plane is likely
to be near crap on the ground. But it isn't obvious how one would
"throttle back" and yet still keep the ram air source. Perhaps ram air
isn't useful if one is throttling back, though. D'Oh!
Second, I think you can forgo all of the slotted holes in the valve for
the runners. Just make the valve cover the two air sources.
Third, instead of actuating the valve from the end caps (where I assume
you're going to put the cable connection), slot the outer housing and
actuate it from very near the intake nipples. Put a pair of large snap
rings on the inside to keep the valve positioned, or maybe just put two
slots in the housing and pin it that way.
Fourth, I assume you're going to make a semi-transparent Rhino rendering
showing the fuel rail, injectors, and intake runner bell mouths. I'm
not assuming too much, am I? :-)
Finally, as for casting it, can you not find two close fitting large
diameter (5") tubes? Might need a pair of slippery O-rings (Teflon?),
but as you're found of saying: a small air leak in the intake is not a
problem.
Russell Kent
" Just make the valve cover the two air sources. " I don't follow your there
Russell.
I searched for the tubes and 5" thin wall tubes are hard to find.
Extrusions would be great but expensive if not off the shelf.
Paul Lamar
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