X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost02.isp.att.net ([207.115.11.52] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2713801 for flyrotary@lancaironline.net; Sun, 03 Feb 2008 18:53:54 -0500 Received-SPF: none receiver=logan.com; client-ip=207.115.11.52; envelope-from=keltro@att.net Received: from fwebmail14.isp.att.net ([207.115.9.154]) by isp.att.net (frfwmhc02) with SMTP id <20080203235314H0200ac831e>; Sun, 3 Feb 2008 23:53:14 +0000 X-Originating-IP: [207.115.9.154] Received: from [4.245.53.37] by fwebmail14.isp.att.net; Sun, 03 Feb 2008 23:53:13 +0000 From: "Kelly Troyer" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] How to tell: High compression rotors Date: Sun, 03 Feb 2008 23:53:13 +0000 Message-Id: <020320082353.6306.47A653E8000D3AF9000018A222230650629B0A02D29B9B0EBF019D9B040A05@att.net> X-Mailer: AT&T Message Center Version 1 (Oct 30 2007) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_6306_1202082793_0" --NextPart_Webmail_9m3u9jl4l_6306_1202082793_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Bob and Ed, My 13B Cosmo is 9.0 to 1......20B should be the same.......... -- Kelly Troyer "Dyke Delta"_13B ROTARY Engine "RWS"_RD1C/EC2/EM2 "Mistral"_Backplate/Oil Manifold -------------- Original message from "Ed Anderson" : -------------- > Bob, the compression for the turbo rotors on some models of the 13B were as > low as around 8.4:1. If that is also true of the 13B, then my opinion is > you will see a considerable improvement in power over the low compression > rotors. I went from the 9.4 to the 9.7:1 rotor on my two rotor and liked > the results. I know that small a difference in compression should not > translate into a terrific power increase, but it seemed make a noticeable > difference. Now the challenge is getting the 9:7:1 - there are not many > used ones out there and those that are can be very worn. Make certain you > check the apex seal slot wear measurements before you stick any in your > engine (actually all of its seal slots should be checked) if using used > ones. If apex seal slot wears past the limit and if you are using the > somewhat brittle stock apex seals, they will break - don't ask me how I > know. > > > One thing make certain you are getting 9:7:1 rotors. If you place a > straight edge across the compression dish and then measure vertically down > until you hit the top of the rotor it should be around 3.8-4 mm. If it > measure more than that it may be the lower compression 9.4:1. But, even the > 9.4:1 should make a noticeable difference IF the stock turbo 20B is using > the 8.4:1 > > Ed > ----- Original Message ----- > From: "bob.kaufmann" > To: "Rotary motors in aircraft" > Sent: Sunday, February 03, 2008 4:44 PM > Subject: [FlyRotary] Low compression rotors > > > > Gang > > > > I have a 20B that I have taken the turbos off and will be using it in an > > aircraft, a RV-10. A friend of mine said that I should use the 9.7 > > compression rotors instead of the turbo rotors. What say you all? > > > > I have pulled the engine off to powder coat the engine mount and if I'm > > going to switch rotors, now is the time before I hang the engine again. I > > have the flat plate on milling machine so I could make plates for the 20B > > if > > people wanted. I think I would be competitive. I would like to do them > > in > > groups of ten if people are interested. > > > > Bob K > > Finished except all the parts aren't together yet. > > > > > > -- > > Homepage: http://www.flyrotary.com/ > > Archive and UnSub: > > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html --NextPart_Webmail_9m3u9jl4l_6306_1202082793_0 Content-Type: text/html Content-Transfer-Encoding: 8bit
Bob and Ed,
     My 13B Cosmo is 9.0 to 1......20B should be the same..........
 
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold




-------------- Original message from "Ed Anderson" <eanderson@carolina.rr.com>: --------------


> Bob, the compression for the turbo rotors on some models of the 13B were as
> low as around 8.4:1. If that is also true of the 13B, then my opinion is
> you will see a considerable improvement in power over the low compression
> rotors. I went from the 9.4 to the 9.7:1 rotor on my two rotor and liked
> the results. I know that small a difference in compression should not
> translate into a terrific power increase, but it seemed make a noticeable
> difference. Now the challenge is getting the 9:7:1 - there are not many
> used ones out there and those that are can be very worn. Make certain you
> check the apex seal slot wear measurements before you stick any in your
> engine (actually all of its seal slots should be ch ecked) if using used
> ones. If apex seal slot wears past the limit and if you are using the
> somewhat brittle stock apex seals, they will break - don't ask me how I
> know.
>
>
> One thing make certain you are getting 9:7:1 rotors. If you place a
> straight edge across the compression dish and then measure vertically down
> until you hit the top of the rotor it should be around 3.8-4 mm. If it
> measure more than that it may be the lower compression 9.4:1. But, even the
> 9.4:1 should make a noticeable difference IF the stock turbo 20B is using
> the 8.4:1
>
> Ed
> ----- Original Message -----
> From: "bob.kaufmann"
> To: "Rotary motors in aircraft"
> Sent: Sunday, February 03, 2008 4:44 PM
> Subject: [FlyRotary] Low compression rotors
>
>
> > Gang
> >
> > I have a 20B that I have taken the turbos off and will be using it in an
> > aircraft, a RV-10. A friend of mine said that I should use the 9.7
> > compression rotors instead of the turbo rotors. What say you all?
> >
> > I have pulled the engine off to powder coat the engine mount and if I'm
> > going to switch rotors, now is the time before I hang the engine again. I
> > have the flat plate on milling machine so I could make plates for the 20B
> > if
> > people wanted. I think I would be competitive. I would like to do them
> > in
> > groups of ten if people are interested.
> >
> > Bob K
> > Finished except all the parts aren't together yet.
> >
> >
> > --
> > Homepage: http://www.flyrotary.com/
> > Archive and UnSub:
> > http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
> < BR>> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
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