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Rusty is right when he says it is taking those of us building P.Ports forever. It would be so much easier if the final product did not have to be stuffed inside a cowl.
The design of the intake manifold to include both ram and alt air has taken me six months, mostly spent on bad ideas that I was slow to realize had fatal flaws. What needed to be brought together (to make ME happy) was cold side fuel, ram and alt air, and accurately tuned pipes, combined and shaped to tuck inside my Tailwind's cowl. A couple of weeks ago, the pieces of the puzzle suddenly fell in place. I just woke up one morning knowing how to do it. I am amazed to be able to say that the intake that will meet all the above objectives, is doable and that I am ordering materials this week as soon as I decide whether to make the first one out of steel or aluminum.
The performance of the P port is well documented. Power Sport has proven that it can operate over a wide power band and deliver the significant HP. Most people I have talked with have recommended a relatively small port, opening late for best performance in our rpm range which is below 7500 rpm. So that is what I have done. There is nothing about building a p port that will take much time or money once the size, timing and intake manifold are figured out.
Jerry
On Wednesday, January 5, 2005, at 01:13 AM, Lehanover@aol.com wrote:
In a message dated 1/4/2005 11:31:46 PM Central Standard Time,
13brv3@bellsouth.net writes:
<< I know PP is one of Lynn's favorite subjects, so maybe he'll chime in here.
I want to believe, really.
Cheers,
Rusty
Richard Sohn has both on his single rotor. I believe he said the side port
had no advantage. From a standstill the Pport is far more tractable than the
bridge ported engine. I have both style engines. If you make your own, you will
be controlling the overlap and the closing point. So the Pport will be as
tractable as you make it.
Others have built the butterfly close to the rotor housing to improve idle
and off idle performance. My car has runners tuned for about 8,800 RPM. Very
short. In the aircraft the runners would be much longer, and there might be an
argument for moving the butterfly to get a good idle. The long runner at well
below ambient pressure provides a large volume that fills with exhaust gas at
idle, acting like a vacuum cleaner. The short runner just has less volume, so it
screws up the idle a bit less.
When I get some time I will build a Pport 13B with well over 200 HP. Starting
with little overlap and a small port and going up to way too big. And dyno
at each step.
We need to get pointed in the right direction on this stuff and quit spinning
our wheels.
If you turbo at very low levels I see a very late closing intake Pport and a
very late opening for very little overlap at all. Off idle would stink a bit,
but once the boost starts to over come some of the reversion caused by
compression, things would pick up nicely. With maybe high pressure mechanical
injection between the spark plugs. just before TDC. Just some ideas
Lynn E. Hanover
Homepage: http://www.flyrotary.com/
Archive: http://lancaironline.net/lists/flyrotary/List.html
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