X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mtiwmhc11.worldnet.att.net ([204.127.131.115] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1022022 for flyrotary@lancaironline.net; Sun, 26 Jun 2005 10:18:49 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.131.115; envelope-from=keltro@att.net Received: from 204.127.135.75 ([204.127.135.75]) by worldnet.att.net (mtiwmhc11) with SMTP id <2005062614180411100o7159e>; Sun, 26 Jun 2005 14:18:04 +0000 Received: from [209.247.222.85] by 204.127.135.75; Sun, 26 Jun 2005 14:18:02 +0000 From: keltro@att.net (Kelly Troyer) To: "Rotary motors in aircraft" Subject: Re: Single Rotor Research Date: Sun, 26 Jun 2005 14:18:02 +0000 Message-Id: <062620051418.3391.42BEB91A000ABADD00000D3F2160466648019D9B040A05@att.net> X-Mailer: AT&T Message Center Version 1 (Feb 14 2005) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_3391_1119795482_0" --NextPart_Webmail_9m3u9jl4l_3391_1119795482_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit George and All, I do not follow !! I am familar with Lynn's suggestion to add slightly more radius to what I call the top edge of the exhaust port.........Are you suggesting additional work to this edge ?? Perhaps a simple drawing would help my simple mind visualize what you are suggesting !! -- Kelly Troyer Dyke Delta/13B/RD1C/EC2 -------------- Original message from "George Lendich" : -------------- > Ernest, > Let me try again. > The leading edge is already radiused or sloped to enhance flow into the > exhaust port, Lynn has suggested a further streamlining of that edge helps > evacuate the exhaust. > The top ( following) square edge helps to block the exhaust from entering > the inlet area. > Now the suggestion to me was to slightly radius this top edge. > My thinking it would help draw in some inlet charge and that's not so good. > However he has said he gets good performance from doing that mod. > I'm unsure !? > George ( down under) > > George Lendich wrote: > > > > > > > > It would also seem that if you radiused the following edge of the > > > exhaust outlet, it provides better exhaust flow and less contamination > > > of the inlet charge at idle. > > > For your digestion! > > > > > > OK. I'm about done digesting, so... > > > > This is completely logical, under the theory that the sharp edge will > > trip the exiting airflow into turbulence. Clean air always flows > > faster. I keep thinking about the exhaust inserts. Ed has the opinion > > that they must be eating up horses to give the noise reduction by > > causing back pressure. But what if the inserts work like a fowler flaps > > and just helps the gas to exit is an orderly manner vs all turbulated? > > Aren't laminar flow aircraft typically quieter than turbulent flow ones? > > > > Has anyone compared the noise produced before and after an exhaust has > > been radiused? > > Has anyone attempted to 'shape' the inserts so that it has a radiused > > leading edge and a tapered trailing edge (ie, aerodynamic)? I know > > they're not very thick, but their thickness is a significant portion of > > the overal exhaust ports size. --NextPart_Webmail_9m3u9jl4l_3391_1119795482_0 Content-Type: text/html Content-Transfer-Encoding: 8bit

George and All,

I do not follow !! I am familar with Lynn's suggestion to add slightly more

radius to what I call the top edge of the exhaust port.........Are you suggesting

additional work to this edge ?? Perhaps a simple drawing would help my simple

mind visualize what you are suggesting !!

--
Kelly Troyer
Dyke Delta/13B/RD1C/EC2

-------------- Original message from "George Lendich" <lendich@optusnet.com.au>: --------------

> Ernest,
> Let me try again.
> The leading edge is already radiused or sloped to enhance flow into the
> exhaust port, Lynn has suggested a further streamlining of that edge helps
> evacuate the exhaust.
> The top ( following) square edge helps to block the exhaust from entering
> the inlet area.
> Now the suggestion to me was to slightly radius this top edge.
> My thinking it would help draw in some inlet charge and that's not so good.
> However he has said he gets good performance from doing that mod.
> I'm unsure !?
> George ( down under)
> > George Lendich wrote:
> >
> > >
> > > It would also seem that if you radiused the following edge of the
> > > exhaust outlet, it provides better exhaust flow and less contamination
> > > of the inlet charge at idle.
> > > For your digestion!
> >
> >
> > OK. I'm about done digesting, so...
> >
> > This is completely logical, under the theory that the sharp edge will
> > trip the exiting airflow into turbulence. Clean air always flows
> > faster. I keep thinking about the exhaust inserts. Ed has the opinion
> > that they must be eating up horses to give the noise reduction by
> > causing back pressure. But what if the inserts work like a fowler flaps
> > and just helps the gas to exit is an orderly manner vs all turbulated?
> > Aren't laminar flow aircraft typically quieter than turbulent flow ones?
> >
> > Has anyone compared the noise produced before and after an exhaust has
> > been radiused?
> > Has anyone attempted to 'shape' the inserts so that it has a radiused
> > leading edge and a tapered trailing edge (ie, aerodynamic)? I know
> > they're not very thick, but their thickness is a significant portion of
> > the overal exhaust ports size.

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