X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from elasmtp-kukur.atl.sa.earthlink.net ([209.86.89.65] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTP id 6629301 for lml@lancaironline.net; Fri, 06 Dec 2013 20:57:00 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.65; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=pZ+W/VsJDwT6yvu5xdhqmxxy+UjzB3OCTa7LRhZLEcRBvOXxQjijA4AqcVGGrRzs; 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 [64.222.159.181] (helo=[192.168.1.24]) by elasmtp-kukur.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1Vp785-0006DO-7m for lml@lancaironline.net; Fri, 06 Dec 2013 20:56:26 -0500 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: multipart/alternative; boundary=Apple-Mail-148-52291226 Subject: Re: [LML] Re: cabin pressure valve vs manifold pressure drop Date: Fri, 6 Dec 2013 20:56:24 -0500 In-Reply-To: To: "Lancair Mailing List" References: Message-Id: <733C3521-BE15-4A75-AA70-26CE0FD00FC1@earthlink.net> X-Mailer: Apple Mail (2.1085) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940dc742afdb02bd1d826a5dfba9b725408350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 64.222.159.181 --Apple-Mail-148-52291226 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 just curious - has anyone on the list experienced what they think is a = compressor stall with the tsio-550? On Dec 4, 2013, at 9:59 AM, pete@leapfrogventures.com wrote: I was told a few years ago that the intercoolers with the pressurized = air takeoff ports ahead of the intercooler required that some air be = bled out through this port (or the =93cold=94 air port we add downsteam = of the intercooler) or a compressor stall can occur. Thus, just closing = off the port is not an option. =20 On the Cirrus and Columbia installations of these same engines, max = engine HP is capped at 310 hp. I wonder if this has something to do = with the compressor stall issues, as neither of their intercoolers has = the pressure takeoff ports like ours do. =20 Pete =20 From: Colyn Case [mailto:colyncase@earthlink.net]=20 Sent: Tuesday, December 03, 2013 9:09 AM To: Lancair Mailing List Subject: Re: [LML] Re: cabin pressure valve vs manifold pressure drop =20 Bob, =20 what would you expect to happen if your system had sonic nozzles on the = hot side and not on the cold, you had set the mixer to "cold" and then = you shut off cabin air? It seems to me that would result in more MP = loss than if you had it on hot. =20 ...which leads to an observation that Craig Berland made some while = back, which is that if the cold-side cabin air plumbing is compromised = (e.g. a clamp lets loose) , you will suffer a loss of engine power. =20 Colyn =20 =20 On Dec 3, 2013, at 11:54 AM, Robert R Pastusek wrote: CWFMD, =20 I=92d need more info to diagnose this completely, but write me directly = and I=92ll try to help. rpastusek@htii.com =20 Some basics on the pressurization system (applies to the IV-P with = Continental TSIO-550 engine ONLY--you didn=92t specify the = aircraft/engine): The engine is designed to =93vent=94 part of the turbocharger output = overboard during normal operation, through what are called =93sonic = nozzles=94 that basically maintain a rather constant flow rate over a = range of pressure differentials. The IV-P (and some other pressurized = Lancairs with big bore Continentals) uses this bleed air to pressurize = the cockpit. The air is routed through a mixer/control box mounted near = the top center of the firewall in the engine compartment. This = gold-colored aluminum can (about 2/3 the height of a quart oil can) has = a cockpit-controlled shuttle valve that allows selection of a mix of hot = air directly from the turbochargers and cooler air that has already = passed through the intercoolers. It also has a separate valve, with = cockpit control, that shuts off airflow to the cabin and diverts it out = the bottom of the engine compartment when cockpit pressurization (and = associated heat) is not needed. =20 As to heat, at full throttle, the turbocharger output air temperature = can be up to 300 degrees, and in the cabin heat on mode, flows pretty = directly into the cabin. With the heat control turned off, the = turbocharger air passes through a pair of air-to-air intercoolers before = heading to the cockpit for pressurization. The problem is that these = intercoolers only lower the temperature; they don=92t deliver =93cold=94 = air out the backside. When the input is at 300, the output is warm, at = best; hot in Texas in the summer. So, without air conditioning, there is = not a good source of really cool air available to pressurize the = cockpit. =20 As to the fixes: First check is to be sure the valves in the controller = are functioning as intended. Second check is to be sure you have sonic = ports installed in your turbocharger output lines that feed to this = controller. The variation you report in MP would tend to indicate there = are no sonic ports installed, and that you=92re getting =93full flow=94 = through the system, rather than restricted flow as intended=85but this = is just a guess at this point=85 not enough data. Talk or write? =20 Bob =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = cwfmd@yahoo.com Sent: Tuesday, December 03, 2013 7:01 AM To: lml@lancaironline.net Subject: [LML] cabin pressure valve vs manifold pressure drop =20 We put a new canopy seal in the IV-P. I fiddled with the cabin pressure = valve to try to reduce or locate a squeal. (My Grainger smoke matches = don't light, with reduced partial pressure of Oxygen at altitude) I = noticed that pulling the cabin pressure control partially out, reduced = the cabin inflow, as expected, but also dropped the manifold pressure by = about 4 inches with a loss of about 50 hp (estimated). This was at = flight level 230. I had not previously noticed this large effect on = manifold pressure, but it could demystify performance changes in = previous data. Who knew the cabin pressure valve affected the "throttle" = setting :) It makes sense because the previous cabin pressure just dumps = overboard at the firewall. Wondering why this is set up this way.... Why = not just close the valve to the cabin, when not needed or wanted, and = leave the manifold pressure in the manifold?? In general, I noticed others have similar issues with the cost of = repair of the Dukes valve. I would rather redesign the system, using the = on-board instrumentation and computers that already know the static = pressure and the cabin pressure. I hot climates I prefer to minimize the = heat entering the cabin, and maybe just use 4-5 psi relief valves to = distribute air flow. I think my system where all the inter-cooled air = routes thru the firewall to under the back seat was designed by Eskimos, = who always need max heating. =20 --Apple-Mail-148-52291226 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 just curious - has anyone on the list experienced = what they think is a compressor stall with the = tsio-550?

On Dec 4, 2013, at 9:59 AM, pete@leapfrogventures.com = wrote:

I was told = a few years ago that the intercoolers with the pressurized air takeoff = ports ahead of the intercooler required that some air be bled out = through this port (or the =93cold=94 air port we add downsteam of the = intercooler) or a compressor stall can occur.  Thus, just closing = off the port is not an option.
 
On the Cirrus and Columbia installations of these = same engines, max engine HP is capped at 310 hp.  I wonder if this = has something to do with the compressor stall issues, as neither of = their intercoolers has the pressure takeoff ports like ours = do.
From: Colyn = Case [mailto:colyncase@earthlink.net] 
Sent: Tuesday, December 03, 2013 = 9:09 AM
To: Lancair Mailing = List
Subject: Re: [LML] Re: cabin = pressure valve vs manifold pressure = drop
what would you expect to happen if your = system had sonic nozzles on the hot side and not on the cold, you had = set the mixer to "cold" and then you shut off cabin air?   It seems = to me that would result in more MP loss than if you had it on = hot.
...which leads to an observation that Craig = Berland made some while back, which is that if the cold-side cabin air = plumbing is compromised (e.g. a clamp lets loose) , you will suffer a = loss of engine power.
On Dec 3, = 2013, at 11:54 AM, Robert R Pastusek = wrote:
CWFMD,
 
I=92d need more info to diagnose this completely, = but write me directly and I=92ll try to help.   
The engine is designed to =93vent=94 part of the = turbocharger output overboard during normal operation, through what are = called =93sonic nozzles=94 that basically maintain a rather constant = flow rate over a range of pressure differentials. The IV-P (and some = other pressurized Lancairs with big bore Continentals) = uses this bleed air to pressurize the cockpit. The air is routed through = a mixer/control box mounted near the top center of the firewall in the = engine compartment. This gold-colored aluminum can (about 2/3 the height = of a quart oil can) has a cockpit-controlled shuttle valve that allows = selection of a mix of hot air directly from the turbochargers and cooler = air that has already passed through the intercoolers.  It also has a = separate valve, with cockpit control, that shuts off airflow to the = cabin and diverts it out the bottom of the engine compartment when = cockpit pressurization (and associated heat) is not = needed.
From:Lancair = Mailing List [ On Behalf Of cwfmd@yahoo.com
 Tuesday, December 03, 2013 = 7:01 AM
To: lml@lancaironline.net
Subject: [LML] cabin pressure valve = vs manifold pressure = drop
We put a new = canopy seal in the IV-P. I fiddled with the cabin pressure valve to try = to reduce or locate  a squeal. (My Grainger smoke matches don't = light, with reduced partial pressure of Oxygen at altitude) I noticed = that pulling the cabin pressure control partially out, reduced the cabin = inflow, as expected, but also dropped the manifold pressure by about 4 = inches with a loss of about 50 hp (estimated). This was at flight level = 230. I had not previously noticed this large effect on manifold = pressure, but it could demystify performance changes in previous data. = Who knew the cabin pressure valve affected the "throttle" setting :) It = makes sense because the previous cabin pressure just dumps overboard at = the firewall. Wondering why this is set up this way.... Why not just = close the valve to the cabin, when not needed or wanted, and leave the = manifold pressure in the = manifold??
  In = general, I noticed others have similar issues with the cost of repair of = the Dukes valve. I would rather redesign the system, using the on-board = instrumentation and computers that already know the static pressure and = the cabin pressure. I hot climates I prefer to minimize the heat = entering the cabin, and maybe just use 4-5 psi relief valves to = distribute air flow. I think my system where all the inter-cooled air = routes thru the firewall to under the back seat was designed by Eskimos, = who always need max = heating.