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 5.3.8) with ESMTP id 4431525 for flyrotary@lancaironline.net; Sun, 15 Aug 2010 10:48:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.0 c=1 a=HvLWZw5dpCgA:10 a=N659UExz7-8A:10 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=WrMfpB0aAAAA:8 a=Ia-xEzejAAAA:8 a=NdDfFvoznTpcvyZ1DwoA:9 a=qjKTRK4wVC9RowKbLfUA:7 a=Iy5FhqXMfG0S2xoNHV-04gebmTwA:4 a=pILNOxqGKmIA:10 a=Qa1je4BO31QA:10 a=1Erk4P5SMDsA:10 a=EzXvWhQp4_cA:10 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:64834] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id 6F/5E-12447-60EF76C4; Sun, 15 Aug 2010 14:47:34 +0000 Message-ID: <483CAFD310CE4AA39BBCC2EB01E91627@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: Turbo Questions Date: Sun, 15 Aug 2010 10:47:33 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="Windows-1252"; reply-type=response Content-Transfer-Encoding: 7bit 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 Well, John, that is the conclusion I also came to as well. I put 9.7:1 rotors in my 91 Turbo block - the increased power was great, although I don't think I got 30 HP over the 9.1:1 rotors. I can spin my 74 x 88 prop 6000-6200 rpm static at 18GPH fuel flow which indicates I am likely producing around 180HP - possible a tad more on cold mornings. Yes, Leon contacted me not too long ago looking for Rusty Duffy. He let me know he was back into rotary adventures after a 2 years absence. So he is still around although apparently not inclined to get back on e mail lists. My hat's off to you for sticking with your turbo project despite the stock turbo failures - provided some pretty convincing data about the suitablity (or rather lack thereof) of the stock rotary turbo for aircraft usage. Ed Ed Anderson Rv-6A N494BW Rotary Powered http://www.andersonee.com http://www.eicommander.com Http://www.dmack.net/mazda/index.html http://www.flyrotary.com -------------------------------------------------- From: "John Slade" Sent: Sunday, August 15, 2010 9:39 AM To: "Rotary motors in aircraft" Subject: [FlyRotary] Re: Turbo Questions > On 8/15/2010 9:03 AM, Ed Anderson wrote: >> The engine doesn't know or care how this increase in pressure comes >> about - well, actually it does. If you use a turbo or supercharger you >> are also heating the air through their compression process (which is why >> you need an intercooler in many cases) thereby moving closer to >> detonation. > Ed, this sentence summarizes the advice I received from the Aussie rotary > expert, Leon Promet (anyone know what became of him?) and others. The way > he put it, using the non-turbo (9.7:1) rotors in a turbo installation gets > you an extra 30 HP "for free" because this part of the increased pressure > doesn't involve heating the air via the turbo. You still have to deal with > the potential detonation either way if mixture and timing are wrong. > > My experience with detonation (or pre-detonation) was much less severe > than yours. I heard 'popping' at high rpm during run-up at around 44MAP. > Reduce the throttle a hair and the popping ceased. This was with a big > fixed pitch prop that I could only turn at around 4900 rpm. I had the > feeling that it was rather like flooring a car in top gear on a hill. > (remember in the old days before ECUs and knock sensors when that would > get you a popping sound?). I was able to fly my first 40 hours with no > issues from detonation by keeping the throttle away from the area that > caused it during runup. I never experienced (or at least heard) any > popping once airborne, even during a high-speed run at 44 MAP and 6300 > rpm. I once tried hooking up a knock sensor to the intercom without > success. I never had any damage to the plugs. > > When I installed the adjustable IVO prop my static rpm when from 4900 to > 5600rpm and the popping sound disappeared (analogous to changing gear on > the hill?). I haven't experienced any popping since. I think Tracy's ECU > does a good job of providing a rich mixture at high rpm to keep you away > from detonation. > > Regards, > John Slade > Cozy IV, N96PM > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > Ed Anderson Rv-6A N494BW Rotary Powered http://www.andersonee.com http://www.eicommander.com Http://www.dmack.net/mazda/index.html http://www.flyrotary.com