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From: "George Lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-981257@logan.com>
Subject: Re: [FlyRotary] Combining ports on 6-port
Date: Thu, 2 Jun 2005 09:44:19 +1000
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Ernst,
I'm more than a little concerned at suddenly increasing a runner volume - if
that's what you mean.
I reflect back to a problem with Steam - when it is expanded into a larger
diameter pipe, it's no longer steam but hot water. The water droplets drop
out of suspension, due to the pressure change.

I feel the same happens with fuel - but perhaps some of the engineers ( on
here) can add further to this.

George (down under)

> Found the answer to the question I had the other day.  On a 6-port, why
> not just combine the two runners in the side housing?
>
> From  http://www.mazdatrix.com/faq/port6p.htm
>
> "If the separate ports (in the end housings) are simply made into one
> large port, the bottom and mid-range torque suffer a lot, and the port
> velocity is compromised as the intake flows from the manifold into the
> intake runner. The intake port timing of this configuration is: later on
> opening than a peripheral port, but roughly equal to intake closing on a
> peripheral port! That's a LOT of timing and port volume for a street car."
>
>
> Bottom and mid-range torque are all but meaningless to us as long as
> it'll idle.  Right?
>
> The port velocity will only be compromised if you were using the stock
> intake that.  I don't know of any airplane builders doing that.  If
> you're building your own anyway, you'd make the runner big enough so
> there isn't an upstream obstruction and maintain the velocity throughout.
>
> It seems to me that joining the outside runners on a 6-port is an
> excellent idea for an airplane application.  Somebody set me straight
> before I do something stupid.
>
> --
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