X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 13 Sep 2010 07:53:02 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-dupuy.atl.sa.earthlink.net ([209.86.89.62] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4464768 for lml@lancaironline.net; Mon, 13 Sep 2010 07:52:11 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.62; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=oXeLCd59zouB+568/lc1dgkr0Qy9528nlGavpGGCPrPsie//AMZ3n2rxwerbLP2k; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.85] (helo=[192.168.1.100]) by elasmtp-dupuy.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1Ov7ZP-0005jj-WB for lml@lancaironline.net; Mon, 13 Sep 2010 07:51:36 -0400 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: multipart/alternative; boundary=Apple-Mail-31--1018666315 Subject: Re: [LML] Re: Engine failure ATC Transcript Super Legacy Twin Turbo TSIO 580 X-Original-Date: Mon, 13 Sep 2010 07:51:35 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <5712C162-4E29-4F43-A844-1768FC586561@earthlink.net> X-Mailer: Apple Mail (2.1081) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940f311ca48a1fcf6649e5c5ce9d9823fb4350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.85 --Apple-Mail-31--1018666315 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii I like that actually. That eliminates the very hot exhaust balance = tube. Also, I don't know if other people see this but one of my turbo's inlet = temps is always hotter than the other. (I think it's the right one). I = always wondered if it had something to do with back pressure in the = transfer tube. My concern is that if the turbo compressed air outputs are not joined = at the air inlet of the engine, then the incoming pressure is not = balanced among the cylinders, which also means the mixture is not = balance unless you have multiple fuel controllers. On Sep 12, 2010, at 8:42 PM, Matt losangeles wrote: > Has anyone heard of the Turbo sr22 Cirrus having this sort of problem. = It does not have the exhaust interconnect that the typical tsio-550 has. = It has instead, two wastegates. There is a cable connecting one to the = other and the one controller moves them both this way. > =20 > Lynn, does your exhaust have an interconnect or does it have two = wastegates like the Cirrus? > =20 > Matt >=20 > From: Gary Casey > To: lml@lancaironline.net > Sent: Fri, September 10, 2010 12:18:12 PM > Subject: [LML] Re: Engine failure ATC Transcript Super Legacy Twin = Turbo TSIO 580 >=20 > The questions below are certainly correct. Another post said that the = two turbos were plumbed to be independent from each other, each with its = own wastegate. Then how was the fuel metered? One could use a separate = fuel control servo on each turbo, but I doubt that it was done that way. = I suspect a single servo fed both turbos, measuring the total air. = That's the difference between the Continental proprietary system and the = Lycoming system built by Precision Airmotive(was Bendix). The Bendix = system measures air flow and the Continental system measures throttle = position and engine speed, with altitude compensated versions being = compensated for manifold pressure. Regardless, having one bank = pressurized to a different pressure than the other makes accurate fuel = metering difficult or impossible. If indeed one bank lost boost it = would be very unlikely that the engine could be made to run on more than = 3 cylinders at a time (and I also suspect that the report of "3,4,6" was = incorrect - it mostly likely was 2,4,6 or 1,3,5. Or it would not be = unlikely that the temp probes were mixed up and never detected. >=20 > When I changed any part of the design I used the rigor of conventional = Failure Modes and Effects Analysis (FMEA) to evaluate all possible = failure modes. That would have driven me (I hope) to provide an intake = manifold interconnect between engine banks. I like single turbos, = partly for that reason. >=20 > Gary Casey > ES, not P, not even T >=20 >=20 > notwithstanding Charlies' comments I don't understand exactly what = happened to 3,4,6. The video says Mark tried moving the mixture both = directions with no success. I'm not understanding why that didn't = help...unless half the cylinders have reduced pressure and other half = have higher pressure so there is not optimal mixture. Also why 3,4,6 = and not 2,4,6. Was this a Lycoming? also, also, why did the plugs = foul so quickly? >=20 > on a Continental the turbo outputs are merged so that if you lose, = e.g. one hose, you would lose pressure on all cylinders. at least then = all cylinders face the same mixture situation. >=20 >=20 >=20 --Apple-Mail-31--1018666315 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii I like that actually.  That eliminates the = very hot exhaust balance tube.
Also, I don't know if other people = see this but one of my turbo's inlet temps is always hotter than the = other.  (I think it's the right one).  I always wondered if it = had something to do with back pressure in the transfer = tube.

  My concern is that if the turbo = compressed air outputs are not joined at the air inlet of the engine, = then the incoming pressure is not balanced among the cylinders, which = also means the mixture is not balance unless you have multiple fuel = controllers.

On Sep 12, 2010, at 8:42 PM, Matt = losangeles wrote:

Has anyone heard of the = Turbo sr22 Cirrus having this sort of problem. It does not have the = exhaust interconnect that the typical tsio-550 has. It has instead, two = wastegates. There is a cable connecting one to the other and the one = controller moves them both this way.
Lynn, does your exhaust have an = interconnect or does it have two wastegates like the Cirrus?
 

From: Gary Casey <casey.gary@yahoo.com>
To: lml@lancaironline.net
Sent: Fri, September 10, 2010 = 12:18:12 PM
 [LML] Re: Engine failure = ATC Transcript Super Legacy Twin Turbo TSIO 580

The questions = below are certainly correct.  Another post said that the two turbos = were plumbed to be independent from each other, each with its own = wastegate.  Then how was the fuel metered?  One could use a = separate fuel control servo on each turbo, but I doubt that it was done = that way.  I suspect a single servo fed both turbos, measuring the = total air.  That's the difference between the Continental = proprietary system and the Lycoming system built by Precision = Airmotive(was Bendix).  The Bendix system measures air flow and the = Continental system measures throttle position and engine speed, with = altitude compensated versions being compensated for manifold pressure. =  Regardless, having one bank pressurized to a different pressure = than the other makes accurate fuel metering difficult or impossible. =  If indeed one bank lost boost it would be very unlikely that the = engine could be made to run on more than 3 cylinders at a time (and I = also suspect that the report of "3,4,6" was incorrect - it mostly likely = was 2,4,6 or 1,3,5.  Or it would not be  unlikely that the = temp probes were mixed up and never = detected.

When I changed = any part of the design I used the rigor of conventional Failure Modes = and Effects Analysis (FMEA) to evaluate all possible failure modes. =  That would have driven me (I hope) to provide an intake manifold = interconnect between engine banks.  I like single turbos, partly = for that reason.
Gary = Casey
ES, not P, not even = T


notwithstanding Charlies' comments I don't = understand exactly what happened to 3,4,6.   The video says Mark = tried moving the mixture both directions with no success.   I'm not = understanding why that didn't help...unless half the cylinders have = reduced pressure and other half have higher pressure so there is not = optimal mixture.   Also why 3,4,6 and not 2,4,6.   Was this a = Lycoming?  also, also, why did the plugs foul so quickly?

on a = Continental the turbo outputs are merged so that if you lose, e.g. one = hose, you would lose pressure on all cylinders.   at least then all = cylinders face the same mixture = situation.

= --Apple-Mail-31--1018666315--