X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0c5) with ESMTP id 770558 for flyrotary@lancaironline.net; Sun, 16 Oct 2005 23:58:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-025-165.carolina.res.rr.com [24.74.25.165]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j9H3vdfV004671 for ; Sun, 16 Oct 2005 23:57:40 -0400 (EDT) Message-ID: <000301c5d2ce$ee9a6940$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Displacement - Again? Date: Sun, 16 Oct 2005 23:57:45 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine I think we are on the same choo choo train,Bob. I mean what kind of folks would we be if we couldn't get fired up about some obscure technical point {:>) Ed ----- Original Message ----- From: "Bob White" To: "Rotary motors in aircraft" Sent: Sunday, October 16, 2005 11:29 PM Subject: [FlyRotary] Re: Displacement - Again? > Thanks Ed, > > I don't disagree with a thing you've said. > > Paul L. (and Dave agreed) says "One rev and one rev only for a four > cycle determines the displacement." I said "This I totally disagree > with. . . . . . . it takes two complete revolutions to get all pistons > to pump that displacement." I think we agree. :) I want one of them > to tell me how to get 2.6L displacement in _one_ revolution. That's > the only issue I have with the 2.6L number. > > My take on the displacement is that fundamentally it has nothing to do > with comparing to something else. It's just a calculated volume. A > piston engine is based on bore, stroke, and number of pistons. To > compare a 2 cycle piston engine with a 4 cycle piston engine I would run > thru a comparison, like you've done below for the rotary, and I would > say a 1.3L 2 cycle engine is equivalent to a 2.6L 4 cycle engine. > I would NOT say the 2 cycle engine is a 2.6L engine. So for the rotary I > calculate the displacement just like I do for the piston engines. Let > the thing run thru a complete cycle and I find that it displaces 3.9L > (the rotors making one complete revolution). Now, using your analysis > below, I would say the 3.9L rotary is equivalent to a 2.6L 4 cycle > piston engine. How displacement relates to output shaft rotation > depends on what kind of engine it is. 2 cycle piston, one rev, 4 > cycle piston, two revs, and rotary three revs. Does that make sense? > > Bob W. > > PS: I just saw Richards comment and your reply. If I had anything > better to do on a quiet Sunday night, I would be doing it. ;) > > > > On Sun, 16 Oct 2005 22:38:14 -0400 > "Ed Anderson" wrote: > >> Been there, done that {:>). If you are going to compare the power >> production of 13B rotary engine with a normal reciprocating engine, then >> the accepted standard for a power cycle (for a four stroke) is 720Deg >> crankshaft degrees of rotation. 720 degrees of a reciprocating engine >> has all cylinders firing be it a 4,6,8 or 12 cylinder engine. >> >> Clearly the 80 CID or 1.3 Liters comes from simplistic sum of the two 40 >> CID chambers per rotor. The 2.6 liters takes a bit more explaining. >> >> Where I believe the controversy comes in is that 720 degrees of a rotary >> leaves two faces of the 13B yet unfired. For all six faces to fire it >> takes 1080 degrees of crankshaft rotation. Each rotor face rotates 120 >> rotor degrees for a complete cycle- since the e shaft is geared 3:1 then >> 120 deg rotor rotation = 3*120 = 360Deg of E shaft rotation. Or another >> way to look at it is 360 deg of rotor rotation ( a complete rotor >> revolution) = 3*360 = 1080 deg of e shaft rotation. >> >> Now you can argue that the rotary has not finished its combustion cycle >> (all chambers firing) until all six faces have fire (1080 deg) - however, >> the accepted standard for a complete cycle of a reciprocating 4 stroke is >> 720 degs. >> >> So IF you are interested in comparing oranges and oranges, then its >> generally accepted you compare only 720 deg of the rotary's rotation to >> equal the 720 deg of a normal 4 stroke reciprocating engine. >> >> IF you do accept that - then that means 4 rotor faces have gone through >> their cycle in 720 deg of e shaft rotation. So at approx 40 CID per face >> we have 4 x 40 = 160 CID for the 720 deg cycle. And that turns out to be >> 2.62 liters of displacement. >> >> Its really no different than adding up the total displacement of all >> the cylinders in a reciprocating engine which do happen to complete a >> power stroke in that standard 720 deg. I think the fact that two faces >> or (80 CID of displacement) have not yet fire with the rotary is what >> bothers folks in this comparison. >> >> But if you are going to compare the power of the two different designs of >> engine you have to pick one or the other as the standard of comparison. >> And keep the parameters the same for both engines. For example: >> >> If you believe the cycle of the rotary is not complete until all six >> faces have fired then you have 6 x 40 = 240 CID in the 1080 degree rotary >> cycle. >> >> We could insist that the reciprocating engine be compared to the 1080 deg >> rotation of the rotary, but then you would have to increase the effective >> displacement of the reciprocating engine to include an additional 1/2 of >> its displacement since it will have gone through another 360 deg of >> rotation to match (720 + 360 = 1080) the rotary cycle of 1080deg. That >> way you again have oranges and oranges. >> >> But, in that case both we and the recip folks could boast about even >> more HP than we do now {:>) >> >> Since I am mainly interested in comparing a rotary with the reciprocating >> engines production of power, I adhere to the 720 deg standard for the >> comparison. >> >> Not taking any sides , but someone asked where the 2.6 liter figure came >> from and I hope I have answered that. >> >> Ed A >> >> >> >> ----- Original Message ----- >> From: "Bob White" >> To: "Rotary motors in aircraft" >> Sent: Sunday, October 16, 2005 9:21 PM >> Subject: [FlyRotary] Re: flyrotary_Web_Archive Re: Banishment >> >> >> > Hi Dave, >> > >> > OK, one revolution of the e-shaft is 1/3 revolution of the rotors. So >> > each rotor has had one intake event. Each face has a calculated >> > displacement of about 650 cc. Two X 650 cc = 1.3L. If you can explain >> > why it's 2.6L, maybe I can send Paul an apology. Or are you just >> > trying to get my goat? :) >> > >> > I'm not trying to create a big discussion on the displacement of the >> > rotary, I just want to understand where that 2.6L per revolution number >> > is comming from. I haven't been able to see it. I think Paul gets it >> > from comparing to a piston engine, and I agree that the 13B compares >> > closest to a 2.6L 4 cycle 4 cylinder engine. >> > >> > Bob W. >> > >> > >> > On Sun, 16 Oct 2005 16:27:59 -0700 >> > David Leonard wrote: >> > >> >> Monty, Glad to have you and you know you will always be welcome here. >> >> However, you are wrong and 'he' is right about the displacement of the >> >> 13B. >> >> It is 2.6L or 159.6 cubic inches to be more exact. >> >> That is the volume of intake on one revolution of the e-shaft. >> >> But I think you knew that, you were just trying to get his goat. ;-) >> >> >> >> -- >> >> Dave Leonard >> >> Turbo Rotary RV-6 N4VY >> >> http://members.aol.com/_ht_a/rotaryroster/index.html >> >> http://members.aol.com/_ht_a/vp4skydoc/index.html >> >> >> >> On 10/16/05, Monty Roberts wrote: >> >> > >> >> > The doctrine of immaculate ingestion. Whereby molecules of air and >> >> > fuel >> >> > magically migrate into a very small, very perfect engine,unsullied >> >> > by the >> >> > mere laws of physics, thereby creating the salvation of the world >> >> > through >> >> > massive power levels. >> >> > In the protestant tradition of placing the individual at the front >> >> > of the >> >> > line rather than at the bottom of the church hierarchy, I will >> >> > henceforth >> >> > place all replies at the TOP of each post. >> >> > Monty >> >> > Which doctrine was that Monty? >> >> > >> >> > Bob W. >> >> > >> >> > >> >> >> > >> > >> > -- >> > http://www.bob-white.com >> > N93BD - Rotary Powered BD-4 (real soon) >> > Prewired EC2 Cables - http://www.roblinphoto.com/shop/ >> > >> > -- >> > Homepage: http://www.flyrotary.com/ >> > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ >> > > > > -- > http://www.bob-white.com > N93BD - Rotary Powered BD-4 (real soon) > Prewired EC2 Cables - http://www.roblinphoto.com/shop/ > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/