The other option is to run a standard butterfly valve as close to the chamber as possible. The older powersport throttle was bored through the housing. There is a different way to do this that is simpler and we're working on it.
Bill JepsonSent from my Verizon Wireless BlackBerry
From: Tracy Crook <tracy@rotaryaviation.com>
Date: Fri, 9 Apr 2010 22:03:06 -0400 To: Rotary motors in aircraft<flyrotary@lancaironline.net> Subject: [FlyRotary] Re: Tuned lengths
"One nice thing about the p-port motor is that the intake is super simple
make. Of course, you've got to build a slide throttle. ;-) "
Just curious Mark, are you just kidding or do you really think the slide throttle is a necessity? When and if I ever build a P-Port engine I'll use a standard throttle body. I don't see a significant advantage to the slide throttle. It's still too far away from the inner port entrance to help the idle. With a conservative port timing the idle is OK for aircraft use anyway. Richard's P Port idled OK using a carburetor and it was a one rotor which has a even harder time at idle.
Tracy
On Fri, Apr 9, 2010 at 8:31 PM, Mark Steitle <msteitle@gmail.com> wrote:
Bill,
One nice thing about the p-port motor is that the intake is super simple make. Of course, you've got to build a slide throttle. ;-)
Mark
On Fri, Apr 9, 2010 at 12:36 PM, Al Gietzen <ALVentures@cox.net> wrote:
My
understanding is that one advantage to using individual throttles as you did
was that it mitigated the effect of pulses between the intakes and tuning
became less critical.
Where
did you get the tubes to weld-up? I’m planning on making a casting
myself but it would nice to know alternate sources.
Bill;
I don’t recall where I got the
tube – there are a number of vendors. I think I bought U-bends
which were then cut and welded. The tube size was chosen to have a circumference
close to match that of the ports. The fabricator then made mandrels to
shape the tubes to match the ports – then welded into the water-jet cut
flange.
Al
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Thursday, April
01, 2010 5:06 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Tuned lengths
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Tuned
lengths
Please
post drawings/photos/specs...Yvon
Some
photos of the intake manifold for the 20B are attached. It is 4.5” from
flange to flange; the TB flange is at a slight angle to fit my installation;
the TB is TWM 3003; 44mm diameter bores.
Another
builder built his from my drawings and had a couple extra made. At least
one is still available. The price is around $1000; I’ll have to check.
That’s a real deal – by the time I had mine fabricated and heat
treated it was over $2000. Let me know if anyone is interested.
Al
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