X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 25 Aug 2009 06:17:43 -0400 Message-ID: X-Original-Return-Path: Received: from betsy.gendns5.com ([65.254.38.234] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3823490 for lml@lancaironline.net; Mon, 24 Aug 2009 23:01:40 -0400 Received-SPF: none receiver=logan.com; client-ip=65.254.38.234; envelope-from=paul@tbm700.com Received: from s01060018f83ecf6d.cg.shawcable.net ([70.72.197.235]:56784 helo=[192.168.3.106]) by betsy.gendns5.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1MfmHP-0003Up-SQ for lml@lancaironline.net; Mon, 24 Aug 2009 23:01:05 -0400 X-Original-Message-Id: <60AF4430-E149-4711-80F5-1456C7C43ABD@tbm700.com> From: paul miller X-Original-To: "Lancair Mailing List" In-Reply-To: Content-Type: multipart/alternative; boundary=Apple-Mail-7-131621246 Mime-Version: 1.0 (Apple Message framework v936) Subject: Re: [LML] IV-P Manifold Pressure Problem X-Original-Date: Mon, 24 Aug 2009 21:00:44 -0600 References: X-Mailer: Apple Mail (2.936) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - betsy.gendns5.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tbm700.com --Apple-Mail-7-131621246 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit If that were to have happened on my TSIO-520 engines I would immediately think the VAPC (variable absolute pressure controller) was operating with a fully closed wastegate and not regulating on takeoff. I think you have the slope controller so I don't know if it is exactly the same situation but I think the WOT operation is identical. In the pattern, it sounds like it is bootstrapping and simply fixed wastegate with changes in MP coming from airspeed changes. The symptom that is interesting is the takeoff problem. If the cabin is pressurized after takeoff and the bleed comes from turbocharger then that would suggest to me that the VAPC thinks it has less MP after takeoff then on the ground. It sounds as if it is permitting a complete close of the wastegate and maximum MP. That would translate into high fuel flows except (my recollection from the TSIO-520) that the maximum fuel flow should be limited to a maximum value in the fuel controller. Also, if you have a maximum pressure relief valve that would pop at roughly 2 inches over maximum MP. From your description, all the safety protection seems to have been bypassed. Does that sound right? Hope it gets resolved quickly. Paul (ex-C414A driver) Miller Calgary At 50 ft AGL the manifold pressure starts to run away I have ordered a new controller and it should be available in the next few days. We have also found that the manifold pressure wonders 0.3 in Hg in level flight and will decrease in a climb and increase in a decent by approximately 1.4 in Hg. --Apple-Mail-7-131621246 Content-Type: text/html; charset=US-ASCII Content-Transfer-Encoding: quoted-printable If that were to have happened = on my TSIO-520 engines I would immediately think the VAPC (variable = absolute pressure controller) was operating with a fully closed = wastegate and not regulating on takeoff. I think you have the = slope controller so I don't know if it is exactly the same situation but = I think the WOT operation is identical. In the pattern, it sounds = like it is bootstrapping and simply fixed wastegate with changes in MP = coming from airspeed changes. The symptom that is interesting is = the takeoff problem. If the cabin is pressurized after takeoff and = the bleed comes from turbocharger then that would suggest to me that the = VAPC thinks it has less MP after takeoff then on the ground. It = sounds as if it is permitting a complete close of the wastegate and = maximum MP. That would translate into high fuel flows except (my = recollection from the TSIO-520) that the maximum fuel flow should be = limited to a maximum value in the fuel controller. Also, if you = have a maximum pressure relief valve that would pop at roughly 2 inches = over maximum MP. =46rom your description, all the safety = protection seems to have been bypassed. Does that sound right? = Hope it gets resolved quickly.

Paul (ex-C414A = driver) Miller

Calgary

At 50 ft AGL the manifold pressure starts to = run away

I have ordered a new controller and it should = be available in the next few days. We have also found that the = manifold pressure wonders 0.3 in Hg in level flight and will decrease in = a climb and increase in a decent by approximately 1.4 in = Hg.

= --Apple-Mail-7-131621246--