X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ey0-f180.google.com ([209.85.215.180] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4586739 for flyrotary@lancaironline.net; Sat, 20 Nov 2010 21:54:17 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.180; envelope-from=msteitle@gmail.com Received: by eyf18 with SMTP id 18so3613582eyf.25 for ; Sat, 20 Nov 2010 18:53:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=oxsZ+cYg9+ibuEIlsylm2fZoXbO2dtW0wflAY+Z5ITQ=; b=a081dGdWBLrxNpLTZtg9QVxy9DmDX/CLv2Tt5T0bmCXjRlfB4/2Cu1dzlwje3AZpTv /8J27re4yew9AwrcaPSLV5LShjzvPI0X7fvhhInwKtpvmGJ3l5+omZywAX8AJciaUng9 7vWgtUxbX4Gf1/DbHXDeT71Gv3bvBqOBovF4Y= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=SVAXePsqJsX1DFXTtBCXYkcwPs92+G5ABx/6jUZOjANNeHZ3tlLyTvaOkSaulizd7x YnNnzaaFt8LnOSaJQwUmUXxc6vA9FtdOp+lQOH4x3W8jMHeGnYXP/uMCDIzrKgBVFhYr c2EnhgXcYLxGCNaBMADut4AiWo5StefSZe8Ss= MIME-Version: 1.0 Received: by 10.213.17.139 with SMTP id s11mr3146791eba.51.1290308020479; Sat, 20 Nov 2010 18:53:40 -0800 (PST) Received: by 10.213.36.17 with HTTP; Sat, 20 Nov 2010 18:53:40 -0800 (PST) In-Reply-To: References: Date: Sat, 20 Nov 2010 20:53:40 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Exhaust Calcuations From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174c3d6a3627af0495873f6b --0015174c3d6a3627af0495873f6b Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Bill, That's one reason why I asked the question about the rotary being more like a 2-stroke when it comes to exhaust design. The other is that there is no exhaust valve to open and close. Instead, there is a revolving door that passes across the exhaust port, never really closing. So, I took Ed's recommendation and ordered the book on how to hot rod the rotary engine. There's a chapter on exhaust design that I'm hoping will explain all this in terms that I can understand. Mark On Sat, Nov 20, 2010 at 8:42 PM, Bill Bradburry w= rote: > Here is where I show my lack of understanding=85. > > > > Isn=92t 40 cu in the size of one rotor and shouldn=92t this calculation b= e > based on the rotor faces instead of the entire rotor? With a recip eng= ine > the exhaust valve on a cylinder opens once every other revolution of the > crankshaft, but with the rotary, a rotor face exhausts every revolution o= f > the e-shaft. So there are twice as many pulses in a rotary header pipe a= s > in a recip header. > > So can the calc for a recip be used for a rotary without some > modifications? > > > > Bill B > > > ------------------------------ > > *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] *O= n > Behalf Of *Ed Anderson > *Sent:* Saturday, November 20, 2010 12:21 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Exhaust Calcuations > > > > Mark, > > > > 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. > > > > 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 var= y > the rpm in the first set of equations until you get the length determined= by > manipulated equation. > > > > 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 you= r > configuration. > > > > Ed > > > > *From:* Mark Steitle > > *Sent:* Saturday, November 20, 2010 11:18 AM > > *To:* Rotary motors in aircraft > > *Subject:* [FlyRotary] Re: Exhaust Calcuations > > > > Ed, > > > > 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 powe= r. > 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 clim= b. > > > > Have you used the header designer tool available from Burns Stainless? Y= ou > need to know all the timing numbers, rpm, etc. I may give it a try and s= ee > 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. > > > > Mark > > > > On Sat, Nov 20, 2010 at 9:55 AM, Ed Anderson > wrote: > > Mark, > > > > Here is the corrected spreadsheet - I've colored the changeable cells blu= e > - you can plug in any rpm and EVO. The rest of the cells are protected t= o > keep from accidently overwriting them. > > > > Ed > > > > 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 > > > --0015174c3d6a3627af0495873f6b Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Bill,=A0

That's one reason why I asked the question = about the rotary being more like a 2-stroke when it comes to exhaust design= . =A0The other is that there is no exhaust valve to open and close. =A0Inst= ead, there is a revolving door that passes across the exhaust port, never r= eally closing. =A0So, I took Ed's recommendation and ordered the book o= n how to hot rod the rotary engine. =A0There's a chapter on exhaust des= ign that I'm hoping will explain all this in terms that I can understan= d.=A0

Mark

On Sat, N= ov 20, 2010 at 8:42 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote= :

Here is where I sh= ow my lack of understanding=85.

=A0<= /p>

Isn=92t 40 cu in t= he size of one rotor and shouldn=92t this calculation be based on the rotor faces instead of the entire rotor?=A0=A0=A0 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. =A0So there are twice as many pulses in a rotary header pipe as in a recip header.

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

=A0<= /p>

Bill B

=A0<= /p>

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

=A0

Mark,

=A0

I did some algebraic manipulations to find H= PL based on a selected HPD (tube diameter) and got an answer.=A0=A0 However, I am somewhat skeptical of it although it does tend to fit with the general theo= ry of larger dia pipes =3D shorter lengths.

=A0

By arbitrary selection an diameter=A0 - you automatically=A0select =A0the rpm factor in the equation (but, its hidden in the HPD value).=A0 The way you check what your new rpm sweet spot=A0 with the arbitrary diameter is to vary the rpm in the first set of equation= s until you get the length determined by manipulated equation.<= /p>

=A0

So the revised equation for 1.8" dia tu= bes gave 27.58" inches for the HPL.=A0 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.

=A0

Ed

=A0

From: Mark Steitle

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

Subject: [FlyRotary] Re: Exhaust Calcuations

=A0

Ed,

=A0

OK, that answers my question. =A0By going with 1-7/8= " OD pipe (.049 wall), it would be tuned for about 7800 rpm. =A0Obviously, this is to= o high for our purposes. =A0I'll go with 1-5/8 (.063 wall) to shoot for 6= 700 rpm peak power. =A0This 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 t= o cruise climb.

=A0

Have you used the header designer tool available fro= m Burns Stainless? =A0You need to know all the timing numbers, rpm, etc. =A0I may give it a try and see what I come up with. =A0I have a test p-port housing that I mad= e up to see if the tube could be welded to the inner liner. =A0So, I can use that with a spare rotor to verify the EVO and EVC numbers. =A0

=A0

Mark


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