X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from sccrmhc12.comcast.net ([204.127.200.82] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1154058 for flyrotary@lancaironline.net; Wed, 14 Jun 2006 11:10:02 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.200.82; envelope-from=kenpowell@comcast.net Received: from smailcenter71.comcast.net ([204.127.205.171]) by comcast.net (sccrmhc12) with SMTP id <2006061415091601200c8lq6e>; Wed, 14 Jun 2006 15:09:16 +0000 Received: from [68.51.59.156] by smailcenter71.comcast.net; Wed, 14 Jun 2006 15:09:16 +0000 From: kenpowell@comcast.net To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] compression ratios Date: Wed, 14 Jun 2006 15:09:16 +0000 Message-Id: <061420061509.3687.4490269C000134B400000E67220076369204040A99019F020A05@comcast.net> X-Mailer: AT&T Message Center Version 1 (Apr 11 2006) X-Authenticated-Sender: a2VucG93ZWxsQGNvbWNhc3QubmV0 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_3687_1150297756_0" --NextPart_Webmail_9m3u9jl4l_3687_1150297756_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Steve, I think you are overestimating the power loss of converting over to NA. See this link: http://www.442.com/oldsfaq/ofcrc.htm. My understanding is that you will only suffer a 2.4 -4.2 HP loss if assuming the NA engine produced 200 HP (depending on a comparison of 9.4 rotors or 9.7 rotors as opposed to the 9.0 turbo rotors). Compression ratio is much overated if you are not trying to make up for radical cam profiles in piston engines. Ken Powell Bryant, Arkansas 501-847-4721 C150 / RV-4 under construction -------------- Original message -------------- From: Steve Brooks > Buly, > With your engine, removing the turbo makes sense. You can probably get enough > horsepower with the NA setup. > > In my case, with a lower compression turbo engine, I'll have to stick with the > turbo to get enough power. > > I have about 42 hours now on my already used stock turbo, with no problems. I > have been nursing it along though, and don't exceed 5-6 lbs of boost on > takeoff, and usually fly at 0-2 lbs of boost max. Sometimes I cruise around > at less power than that to conserve fuel, if I'm just flying around. > > I do think that the stock turbo is going to fail, and I have all of the parts > to convert to a T04 turbo, which appears to be the best long term turbo > solution. > > As I recall, when Dave had his turbo trouble, he gutted the turbo, and still > used his same exhaust system. Is that what you did, or did you redo your > exhaust ? > > Steve Brooks > > > > > On Tuesday 13 June 2006 11:21 pm, Bulent Aliev wrote: > > On Jun 13, 2006, at 10:13 PM, John Slade wrote: > > > Joe, Buly > > > I think the bottom line on my "escapades" is that the stock turbo > > > just isn't up to the task. So far I have about 25 hours on my T04 > > > Turbonetics + external wastegate setup with zero problems. The > > > engine is purring very smoothly these days. Just a matter of using > > > the right tools for the job. > > > John > > > > Just came from the hangar. Managed to convert the engine to NA in 3 > > hours. Didn't run it since it was almost 11PM and I was missing one > > plug for the cooling port for the turbo. > > While doing it, I opened up John's old stock turbo that he imported > > from NZ. Many of the turbine blades were missing chunks. > > That convinced me that it was the right thing to do. At the moment > > I'm not up-to spending another 2G's for a T4 turbo after I just spent > > $2,400 for a prop. Hope I'm able to spin the prop to the static RPM > > needed? The good part is I can convert it to a 2 blade fast :) > > Buly > > > > -- > > Homepage: http://www.flyrotary.com/ > > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ --NextPart_Webmail_9m3u9jl4l_3687_1150297756_0 Content-Type: text/html Content-Transfer-Encoding: 8bit
Steve,
I think you are overestimating the power loss of converting over to NA.  See this link: http://www.442.com/oldsfaq/ofcrc.htm.  My understanding is that you will only suffer a 2.4 -4.2 HP loss if assuming the NA engine produced 200 HP (depending on a comparison of 9.4 rotors or 9.7 rotors as opposed to the 9.0 turbo rotors).  Compression ratio is much overated if you are not trying to make up for radical cam profiles in piston engines.

Ken Powell
Bryant, Arkansas
501-847-4721
C150 / RV-4 under construction
 
-------------- Original message --------------
From: Steve Brooks <prvt_pilot@yahoo.com>

> Buly,
> With your engine, removing the turbo makes sense. You can probably get enough
> horsepower with the NA setup.
>
> In my case, with a lower compression turbo engine, I'll have to stick with the
> turbo to get enough power.
>
> I have about 42 hours now on my already used stock turbo, with no problems. I
> have been nursing it along though, and don't exceed 5-6 lbs of boost on
> takeoff, and usually fly at 0-2 lbs of boost max. Sometimes I cruise around
> at less power than that to conserve fuel, if I'm just flying around.
>
> I do think that the stock turbo is going to fail, and I have all of the parts
> to convert to a T04 turbo, which appears to be the best long term turbo
> solut ion.
>
> As I recall, when Dave had his turbo trouble, he gutted the turbo, and still
> used his same exhaust system. Is that what you did, or did you redo your
> exhaust ?
>
> Steve Brooks
>
>
>
>
> On Tuesday 13 June 2006 11:21 pm, Bulent Aliev wrote:
> > On Jun 13, 2006, at 10:13 PM, John Slade wrote:
> > > Joe, Buly
> > > I think the bottom line on my "escapades" is that the stock turbo
> > > just isn't up to the task. So far I have about 25 hours on my T04
> > > Turbonetics + external wastegate setup with zero problems. The
> > > engine is purring very smoothly these days. Just a matter of using
> > > the right tools for the job.
> > > John
> >
> > Just came from the hangar. Managed to convert the engine to NA in 3
> > hours. Didn't run it since it was almost 11PM and I wa s missing one
> > plug for the cooling port for the turbo.
> > While doing it, I opened up John's old stock turbo that he imported
> > from NZ. Many of the turbine blades were missing chunks.
> > That convinced me that it was the right thing to do. At the moment
> > I'm not up-to spending another 2G's for a T4 turbo after I just spent
> > $2,400 for a prop. Hope I'm able to spin the prop to the static RPM
> > needed? The good part is I can convert it to a 2 blade fast :)
> > Buly
> >
> > --
> > Homepage: http://www.flyrotary.com/
> > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/
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