X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4586780 for flyrotary@lancaironline.net; Sat, 20 Nov 2010 23:22:34 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=uESSSoDEku2quKX/oFXS2Smn5+55LTFcWFr5T5T8nFs= c=1 sm=0 a=uD6Wf0l6qdcA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=Ia-xEzejAAAA:8 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=7g1VtSJxAAAA:8 a=ISifT36N9HeFMn2p8jcA:9 a=kahbVwmgY3d_Qh3UxNgA:7 a=KbR1es76K-h8MychTYmHRJTf3hcA:4 a=wPNLvfGTeEIA:10 a=Qa1je4BO31QA:10 a=EzXvWhQp4_cA:10 a=vZseifpddZsiFqcd:21 a=WznyIod433DY895d:21 a=pedpZTtsAAAA:8 a=pGLkceISAAAA:8 a=UdTeXeg2jTB_6wQ6LZAA:9 a=zn78s3nJi-YYH3SkRzkA:7 a=HzwaeNcykz4cee3JEuMZ7YXpK2MA:4 a=eJojReuL3h0A:10 a=MSl-tDqOz04A:10 a=rV8WajEEsic8DIAp:21 a=ZHXasuLFuIlbibsv:21 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:63825] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 32/22-07087-66E98EC4; Sun, 21 Nov 2010 04:21:59 +0000 Message-ID: <41AADFC927794923983CD3A772D78440@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: Exhaust Calcuations Date: Sat, 20 Nov 2010 23:21:39 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002D_01CB8909.AF3C0B90" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_002D_01CB8909.AF3C0B90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bill, Without the original document in which the theory lead to the = equations there is no way to be certain. But, apparently at least the = diameter of the exhaust tube is based (in part) on the amount of gas it = is expected to carry - ergo, the need to know whether the gas volume is = based on 40 cid cylinder or a 100 cid cylinder rather than the number of = rotor faces. At least that seems to make sense to me. More cylinder = volume would imply needing a larger diameter tube.=20 Second, the length of the exhaust tube is apparently base on the = scavenging effect of the reflected "suction" wave and the rate of = opening and closing of the exhaust port - so there could be that the = actual length for the rotary should be 1/2 of what the equation for a 4 = stroke piston engine since a 2 stroke engine (which the rotary acts like = exhaust wise) would do just that - just don't know, but that would be = my best guess. None of this is simply, but my experience is that you can work it out = using either rotor reference (rotor rpm, rotor degs) or e shaft = reference (which seems to be the way the books mostly do it) as long as = you stay consistent. My preference is to work it out rotor reference = (makes my head hurt less) and then convert every thing to e shaft = reference. Ed From: Bill Bradburry=20 Sent: Saturday, November 20, 2010 9:42 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Exhaust Calcuations Here is where I show my lack of understanding.. =20 Isn't 40 cu in the size of one rotor and shouldn't this calculation be = based on the rotor faces instead of the entire rotor? With a recip = engine the exhaust valve on a cylinder opens once every other revolution = of the crankshaft, but with the rotary, a rotor face exhausts every = revolution of the e-shaft. So there are twice as many pulses in a = rotary header pipe as in a recip header. So can the calc for a recip be used for a rotary without some = modifications? =20 Bill B =20 -------------------------------------------------------------------------= ------- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Ed Anderson Sent: Saturday, November 20, 2010 12:21 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Exhaust Calcuations =20 Mark,=20 =20 I did some algebraic manipulations to find HPL based on a selected HPD = (tube diameter) and got an answer. However, I am somewhat skeptical of = it although it does tend to fit with the general theory of larger dia = pipes =3D shorter lengths. =20 By arbitrary selection an diameter - you automatically select the rpm = factor in the equation (but, its hidden in the HPD value). The way you = check what your new rpm sweet spot with the arbitrary diameter is to = vary the rpm in the first set of equations until you get the length = determined by manipulated equation. =20 So the revised equation for 1.8" dia tubes gave 27.58" inches for the = HPL. You vary the rpm value in the first equations until you get an HPL = of 27.58" and you get an rpm of approx 7900 - so I agree, probably too = high for your configuration. =20 Ed =20 From: Mark Steitle=20 Sent: Saturday, November 20, 2010 11:18 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Exhaust Calcuations =20 Ed,=20 =20 OK, that answers my question. By going with 1-7/8" OD pipe (.049 wall), = it would be tuned for about 7800 rpm. Obviously, this is too high for = our purposes. I'll go with 1-5/8 (.063 wall) to shoot for 6700 rpm peak = power. This is typically the rpm I see on ground roll and early climb = before I start adjusting the prop down to a lower rpm to transition to = cruise climb.=20 =20 Have you used the header designer tool available from Burns Stainless? = You need to know all the timing numbers, rpm, etc. I may give it a try = and see what I come up with. I have a test p-port housing that I made = up to see if the tube could be welded to the inner liner. So, I can use = that with a spare rotor to verify the EVO and EVC numbers. =20 =20 Mark =20 On Sat, Nov 20, 2010 at 9:55 AM, Ed Anderson = wrote: Mark,=20 =20 Here is the corrected spreadsheet - I've colored the changeable cells = blue - you can plug in any rpm and EVO. The rest of the cells are = protected to keep from accidently overwriting them. =20 Ed =20 Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html =20 ------=_NextPart_000_002D_01CB8909.AF3C0B90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Bill, Without the original document in which the = theory=20 lead to the equations  there is no way to be = certain.  But,=20 apparently at least the diameter of the exhaust tube is based (in part) = on the=20 amount of gas it is expected to carry - ergo, the need to know whether = the gas=20 volume is based on 40 cid cylinder or a 100 cid cylinder rather than the = number=20 of rotor faces.  At least that seems to make sense to me.  = More=20 cylinder volume would imply needing a larger diameter tube. =
 
Second, the length of the exhaust tube is = apparently=20  base on the scavenging effect of the reflected "suction" wave and = the rate=20 of opening and  closing of the exhaust port -  so there = could be=20 that the actual length for the rotary should be 1/2 of what the equation = for a 4=20 stroke piston engine since a 2 stroke engine (which the rotary acts like = exhaust=20 wise) would do just that  - just don't know, but that would be my = best=20 guess.
 
None of this is simply, but my experience is = that you can=20 work it out using either rotor reference (rotor rpm, rotor degs) or e = shaft=20 reference (which seems to be the way the books mostly do it) as long as = you stay=20 consistent.  My preference is to work it out rotor reference (makes = my head=20 hurt less) and then convert every thing to e shaft = reference.
 
Ed
 

Sent: Saturday, November 20, 2010 9:42 PM
Subject: [FlyRotary] Re: Exhaust = Calcuations

Here is where = I show my=20 lack of understanding=85.

 

Isn=92t 40 cu = in the size=20 of one rotor and shouldn=92t this calculation be based on the rotor = faces instead=20 of the entire rotor?    With a recip engine the exhaust = valve on=20 a cylinder opens once every other revolution of the crankshaft, but with = the=20 rotary, a rotor face exhausts every revolution of the e-shaft.  So = there=20 are twice as many pulses in a rotary header pipe as in a recip=20 header.

So can the = calc for a=20 recip be used for a rotary without some=20 modifications?

 

Bill=20 B

 

From:=20 Rotary motors in aircraft=20 [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Ed Anderson
Sent: Saturday, November 20, 2010 = 12:21=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: Exhaust=20 Calcuations

 

Mark,=20

 

I did some algebraic = manipulations=20 to find HPL based on a selected HPD (tube diameter) and got an=20 answer.   However, I am somewhat skeptical of it although it = does tend=20 to fit with the general theory of larger dia pipes =3D shorter=20 lengths.

 

By arbitrary selection an=20 diameter  - you automatically select  the rpm factor in = the=20 equation (but, its hidden in the HPD value).  The way you check = what your=20 new rpm sweet spot  with the arbitrary diameter is to vary the rpm = in the=20 first set of equations until you get the length determined by = manipulated=20 equation.

 

So the revised equation = for 1.8" dia=20 tubes gave 27.58" inches for the HPL.  You vary the rpm value in = the first=20 equations until you get an HPL of 27.58" and you get an rpm of approx = 7900 - so=20 I agree, probably too high for your=20 configuration.

 

Ed

 

From: Mark Steitle=20

Sent: Saturday,=20 November 20, 2010 11:18 AM

To: Rotary motors in = aircraft=20

Subject:=20 [FlyRotary] Re: Exhaust=20 Calcuations

 

Ed,

 

OK, that answers my question.  By going = with 1-7/8"=20 OD pipe (.049 wall), it would be tuned for about 7800 rpm. =  Obviously, this=20 is too high for our purposes.  I'll go with 1-5/8 (.063 wall) to = shoot for=20 6700 rpm peak power.  This is typically the rpm I see on ground = roll and=20 early climb before I start adjusting the prop down to a lower rpm to = transition=20 to cruise climb.

 

Have you used the header designer tool = available from=20 Burns Stainless?  You need to know all the timing numbers, rpm, = etc.=20  I may give it a try and see what I come up with.  I have a = test=20 p-port housing that I made up to see if the tube could be welded to the = inner=20 liner.  So, I can use that with a spare rotor to verify the EVO and = EVC=20 numbers.  

 

Mark

 

On Sat, Nov 20, 2010 at 9:55 AM, Ed Anderson = <eanderson@carolina.rr.com&g= t;=20 wrote:

Mark,=20

 

Here is the corrected = spreadsheet -=20 I've colored the changeable cells blue - you can plug in any rpm and = EVO. =20 The rest of the cells are protected to keep from accidently overwriting=20 them.

 

Ed

 

Edward L. = Anderson
Anderson = Electronic=20 Enterprises LLC
305 = Reefton=20 Road
Weddington, NC = 28104
http://www.andersonee.com
http://www.eicommander.com


--
Homepage:=20  http://www.flyrotary.com/
Archive and UnSub: =   http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l

 

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