Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.93.67.83] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2588308 for flyrotary@lancaironline.net; Sun, 21 Sep 2003 20:01:55 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-02.southeast.rr.com (8.12.5/8.12.2) with SMTP id h8LNw3pN028517 for ; Sun, 21 Sep 2003 19:58:04 -0400 (EDT) Message-ID: <002701c3809c$754c6420$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: DIE Power Calculations Date: Sun, 21 Sep 2003 19:59:56 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 ----- Original Message ----- From: To: "Rotary motors in aircraft" Sent: Sunday, September 21, 2003 3:43 PM Subject: [FlyRotary] Re: DIE Power Calculations > Ed, > Please bring copies (electronic is OK) to Tracy's. I am interested in > understanding the math and would like to work thru the theory. Even though I'm > planning on a peripheral port engine this is really interesting stuff. > Besides, if I were to come up with a RX-8 motor then I might need this info. > > Also, you guys need to come to Tracy's and Laura's Fly-in. More fun than > Oshkosh! I'm driving 13 hours to get there and consider it time well spent. > You won't be sorry. > > Ken Powell Hi Ken, Will be good to see you again. Believe it or not, when you see how simple the equations develop (not kidding), you'll hit yourself in the forehead with "Of course". Well, at least that is what the one local rotary enthusiasts did when I gave him the briefing. In fact once, I got him on track, he was jumping ahead with the next logical step - was playing havoc with my presentation timing {:>). Once you see DIE=>Ta=Tr (if not before) all will start to fall into place. In other words, the equations are no challenge to understand. I guess I could try to map them into a polar coordinate system to make it a bit more exciting. {:>) The interpretation can be a bit more of a bite, but not much more. I took a quick look at the RX-8 intake system (well, as much as I could tell from a couple of photographs and schematics (since I haven't seen one yet). At least from the initial cut, it appears that they have decided on a different intake concept. For example, the strong pulse created when a 13B intake port opens is due to the exhaust gas residue held over from the exhaust stroke overlap. Welllll, the Renesis does not have that exhaust/intake overlap anymore, because they now have the exhaust port in the side housing (in fact their literature makes a point of this). So that implies to me that the powerful exhaust residue created pulse is no longer there. There is some benefit to be gained from the "inertia pulse" created when the port is closed (that effect is still there), but it would seem that without the "exhaust Pulse" created wave the DIE effect would be considerably diminished. But, remember what I said --- the DIE is an adjunct to a fundamentally sound induction configuration. It appears that they decided to capture that power with longer retention of the combustion cycle gases (later exhaust port opening) at the lower RPMs and by increased RPM (lighter rotors) at the higher RPM. I ,of course, could be wrong - not even having seen the engine, but that's my first cut. No saying NO DIE, but if there- I believe its considerably reduced. See you in October Ed Anderson .