I thought we might have the same deal here.
     > Paul Yaw also seems adamant about flowbench testing when modifying systems
     > and parts: http://www.yawpower.com/Flow%20Testing.html
     >
     > I know we run fairly low speeds compared to racers, but everything counts, I
     > guess.....
     >
     > Bill, you say that manifolds usually flow more than the engine can take, but
     > what about fuel/air ratio?
     > Airmass is normally measured only in one spot, before you split the air into
     > individual runners. If the flow is not absolutely the same in every runner
     > you never get the same ratio for each rotor. Unless you start to measure
     > airmass in every runner - too big an installation.
     >
     > Any ideas for a cheap flowbench? Not necessarly for the finest differences
     > for porting or so, just to match intake runners....
     >
     > Thomas J.

Thomas and Group,
 While not discounting Paul's comments about maximum power, (We
should optimize runner lengths on the dyno if possible) the spread of
WORKABLE lengths will be fairly large. If you inject into the tube as
opposed to the bellmouth the charge will be adaquately mixed in the
chamber. Paul Yaw is refering to maximum output engines used for
racing. With the use of electronic fuel injection and O2 sensors we
can map a functional fuel/air curve rather quickly. It won't be perfect
but will be closer than some people ever get carburators!
 The fact is that even if both rotors don't put out exactly the same
amount of power the engine will run fine thank you. We really shouldn't
actually need the MAXIMUM power the engine can put out. In my
case I will be de-rating my engine 40% from what it makes in the car,
and that will be more than enough. 20B producing 210-250 HP.
Al Gitezen (sorry if I hacked your name Al) has already seen 275 HP
normally aspirated in true dyno tests. The optimum intakes and
exhaust WILL improve our fuel consumption in cruise a lot, which is
what we really need the most. Few of us will be running flat out in a
Sun 'n Fun 100. We seem to be approaching a workable layout.
Thanks to the efforts of Paul, Jerry, Ed and others we will be able to fit
things in. The most attention needs to be paid to the airworthyness
of the support systems. There are many rotary powered planes flying
now. The problem is to be sure the cooling, fuel and oil systems are
as bulletproof as we can make them. None of the rotary aircraft that
have had failures had a horsepower "problem". Can we all use more
sure, but it's more important that we keep making what we already
have. End of rant.
Bill Jepson

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