Return-Path: Received: from [204.127.202.56] (HELO sccrmhc12.comcast.net) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 593608 for flyrotary@lancaironline.net; Thu, 06 Jan 2005 14:05:51 -0500 Received-SPF: none receiver=logan.com; client-ip=204.127.202.56; envelope-from=kenpowell@comcast.net Received: from 204.127.205.148 ([204.127.205.148]) by comcast.net (sccrmhc12) with SMTP id <2005010619043401200p293qe>; Thu, 6 Jan 2005 19:04:34 +0000 Received: from [166.102.160.133] by 204.127.205.148; Thu, 06 Jan 2005 19:04:33 +0000 From: kenpowell@comcast.net To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: P-Port stuff- was Re: RV-3 engine rebuild Date: Thu, 06 Jan 2005 19:04:33 +0000 Message-Id: <010620051904.7311.41DD8BBF000264B700001C8F220073544604040A99019F020A05@comcast.net> X-Mailer: AT&T Message Center Version 1 (Dec 17 2004) X-Authenticated-Sender: a2VucG93ZWxsQGNvbWNhc3QubmV0 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_7311_1105038273_0" --NextPart_Webmail_9m3u9jl4l_7311_1105038273_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit 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 78º BTDC and close at 75º 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 > > > > --NextPart_Webmail_9m3u9jl4l_7311_1105038273_0 Content-Type: text/html Content-Transfer-Encoding: 8bit

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 78º BTDC and close at 75º 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
>
>
>
>

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