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Date: Thu, 6 Jan 2005 16:30:16 -0500
Subject: Re: [FlyRotary] Re: P-Port stuff-  was Re: RV-3 engine rebuild
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From: Jerry Hey <j-winddesigns@thegrid.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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Bob,   This is like waiting for the baby to be born.  On one hand I'm 
looking forward to it, but  there is this anxiety about it being 
functional......Jerry

On Thursday, January 6, 2005, at 04:15  PM, Bob White wrote:

> I figured worst case it has to breathe better than the cast iron
> manifold with a straight pipe.  I just hope it muffles pretty good too.
> On the inlet side, I have a street port which won't flow as well as 
> your
> Pport Jerry.
>
> When I was looking at tuned pipes, it seemed like the correct length
> ended up with the muffler at a very awkward location so I had sort of
> given up on tuning them anyway.
>
> If your exhaust system flows as well as a stock exhaust and cuts the
> sound level to something I can fly with I'll consider it a success.
>
> Bob White
>
>
>
> On Thu, 6 Jan 2005 15:19:49 -0500
> Jerry Hey <j-winddesigns@thegrid.net> wrote:
>
>>> Ken,  There are no test results.   It is all theory  and wishful
>>> thinking at this time.  Bob White bought an exhaust system, even
>>> though it is unproven, and he will be the first to test it.  I am
>>> sure
>>>  your comments have gotten  his attention today.  I forget how long
>>>
>>> the tuned exhaust pipe is  supposed to be.  I do recall  it was long
>>>  enough there was no hope of getting one inside the cowl and then
>>>  there
>>> is that muffler hanging out in the breeze. I can't see that on a
>>> Tailwind.  Drag and weight are penalties of the tuned exhaust. As
>>> far  as performance is concerned it might be a wash.  No one knows
>>> until we  do the tests.
>>>  BTW,  the exhaust pipe on my system has much greater capacity than
>>> the combined two inch pipes of a tuned system.  Easy breathing is
>>> what  I am hoping for.   Jerry
>>>
>
>
>>
>> On Thursday, January 6, 2005, at 02:04  PM, kenpowell@comcast.net
>> wrote:
>>
>>> Hi Jerry,
>>> As you know I am also a great proponent of Pport.  Since I am
>>> building  a RV-4 room is a problem under the cowl (Rusty knows what
>>> I mean!).   While your exhaust would solve many problems for me I
>>> think you are  going to be disappointed in the HP output without the
>>> scavenging  effects of a properly tuned (and pipes merged) exhaust.
>>> I hope you  prove me wrong, but I hope you are flexible in your
>>> design to add full  length pipes.  I suspect the untuned exhaust may
>>> cost as much as 30 HP  (yes, this is a real swag without any data to
>>> back it up so it isn't  worth much).  Do you have any test results
>>> (from anybody) to show the  results of a short untuned pipe?
>>
>>> Ken Powell
>>> Bryant, Arkansas
>>> .
>>>
>
>>>
>>> -------------- Original message --------------
>>>
>>>>
>>>>
>>>> On Thursday, January 6, 2005, at 01:28 PM, Russell Duffy wrote:
>>>>
>>>>
>>>> My p ports open at 78__ BTDC and close at 75__ ABDC. This
>>>> drawing shows how much later the ports open in comparison with the
>>>> Leman P Port and how they close at nearly the same time. According
>>>> to calculations made by Rolf Peiffer who helped me a lot, my
>>>> little port has sufficient capacity up to 8000 rpm. After that you
>>>> would want to go bigger. The exhaust port was left stock with the
>>>> splitters in. . JerryArialFFFF,0000,0000
>>>> r>
>>>>
>>>>
>>>>
>>>> ArialFFFF,0000,0000Thanks
>>>> for the info, and pic Jerry. Do you have an estimate of how much
>>>> HP you expect to make at 7500 rpm? And can you get that thing
>>>> running in the next month, so it will be easier for me to decide
>>>> what to do :-)
>>>>
>>>>
>>>>
>>>> ArialFFFF,0000,0000Cheers,
>>>> or>
>>>>
>>>> ArialFFFF,0000,0000Rusty
>>>>>
>>>>
>>>>
>>>>
>>>> Rusty, The hp question???? A worse case scenario I feel would be
>>>> 230 hp at 7500. I think around 250 hp is realistic if we can get
>>>> it up to its potential. It depends on so many factors that will
>>>> have to be ironed out on the dyno. I have a 2:17 drive and a 800
>>>> lb airplane so if I equal PowerSport's performance of 215 at 6000
>>>> that would be sufficient to get the heart pumping on climb out.
>>>> That said, I think PowerSport's intake is too long and also they
>>>> could benefit
>>> from
>>>> ram air. So maybe I will do a little better then they have. My
>>>> exhaust is a free flowing, zero back pressure design and I am
>>>> hoping it will help too. Best thing for you to do is to haul that
>>>> engine to Lynn"s and knock out a p port in a couple of days. Jerry
>>>>
>>>>
>>>>
>>>>
>>>
>>
>
>
> -- 
> http://www.bob-white.com
> N93BD - Rotary Powered BD-4 (soon)
>
>>>  Homepage:  http://www.flyrotary.com/
>>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>