X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 05 Sep 2013 09:40:48 -0400 Message-ID: X-Original-Return-Path: Received: from qmta08.westchester.pa.mail.comcast.net ([76.96.62.80] verified) by logan.com (CommuniGate Pro SMTP 6.0.6) with ESMTP id 6455108 for lml@lancaironline.net; Thu, 05 Sep 2013 07:59:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=76.96.62.80; envelope-from=jmorgan1023@comcast.net Received: from omta23.westchester.pa.mail.comcast.net ([76.96.62.74]) by qmta08.westchester.pa.mail.comcast.net with comcast id MPpi1m0041c6gX858Pz28l; Thu, 05 Sep 2013 11:59:02 +0000 Received: from [192.168.1.102] ([24.11.157.196]) by omta23.westchester.pa.mail.comcast.net with comcast id MPz11m00W4EXR5U3jPz1QN; Thu, 05 Sep 2013 11:59:02 +0000 From: Jack Morgan Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: multipart/alternative; boundary="Apple-Mail=_D1EF923D-AD03-420C-984E-3C9B5149C1E0" Subject: IVP pressurization X-Original-Date: Thu, 5 Sep 2013 07:59:00 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <583F2643-4905-4C31-9059-087438D33094@comcast.net> X-Mailer: Apple Mail (2.1283) --Apple-Mail=_D1EF923D-AD03-420C-984E-3C9B5149C1E0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Hi John, I fabricated a wedge from scraps which held the controller full closed = with slight tension. This allows you to confirm the tub and controller = seals are solid.The controller manufacturer confirmed this was good = practice. If you use two shop vacs (one blowing into the next) you will = generate sufficient pressure to both hear and feel any leaks from inside = and outside the cabin. It is also important to have someone on the = outside listen and feel for leaks as well. Prop the gear doors open and = have the outside person stick his head in each gear well. Be sure to = remove the wedge before doing any flying. You should be able to hear the controller motor run when you change the = cabin altitude setting to insure it is wired properly. The controller is = very reliable so it would be the last thing I would suspect. With the controller set 3,000 feet above the airport you should be able = to feel substantial warm air blowing from the vents at pattern altitude = and cruise power. The air should get hot when you change the mixing = valve setting from the coldest to a bit warmer. With the the controller set 1,000 feet above the airport the cabin = should climb right up to 4.5 psi as you climb and then remain at 4.5 psi = as you climb further. Hope the above helps. Send an email if you want to discuss further. It = took me a few tries to really get it right. Jack Morgan On Sep 5, 2013, at 6:01 AM, Lancair Mailing List wrote: > From: John Barrett <2thman1@gmail.com> > Subject: IVP pressurization > Date: September 4, 2013 7:42:10 AM EDT > To: lml@lancaironline.net >=20 >=20 > Having trouble getting my pressurization to work effectively. > I did my best to seal the pressure vessel but never got above .25 PSID = with my 6 horse shop vac. Used both pressure and vacuum to check for = leaks. No smoke but used a down feather and then a stethoscope with = tympanic membrane removed. Outflow valve is covered during these tests. >=20 > After lots of frustration i hired a guy who has built and/or = pressurized about a dozen IVPs to come take a look. He determined using = smoke that there were a couple of slight improvements to be made mostly = in the wire bundles through the aft pressure bulkhead and after doing = this he declared the vessel seal very good. =20 >=20 > So we deduced that maybe the shop vac is not as efficient at blowing = air as I thought, but my flying experience with the aircraft is that it = doesn't do much better than the .25 PSID in flight up to 14.5K ft. =20 >=20 > Wondering why there is inadequate pressurization with a good pressure = vessel leads to thoughts of outflow valve problems. I bought the device = with the kit in 1996 so it occurs to me the valve could be dirty or = rubber diaphragm could be failing, etc. I removed the outflow valve = yesterday and tried to examine the parts. i lubricated the mandrel that = the poppet valve slides on with a very small spritz of LPS1 lubricant in = case there was stiction there. I did notice that with the poppet valve = manually moved to the furthest closed position the diaphragm still had = somewhere around a 1/32" gap at the seating perimeters. Should the air = pressure in flight fill that diaphragm to close the gap or does this = indicate the valve needs servicing? >=20 > Finally is there a way short of the manual dump switch to keep the = system from pressurizing better than what I see by mismanaging the = controller? Am I just setting the pressurization up wrong? Have only = been up to 3,000 ft elevation airports, (KRDM) and lower - most at sea = level. >=20 > Thanks for any help. >=20 > John Barrett --Apple-Mail=_D1EF923D-AD03-420C-984E-3C9B5149C1E0 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 Hi = John,

I fabricated a wedge from scraps which held the = controller full closed with slight tension. This allows you to confirm = the tub and controller seals are solid.The controller manufacturer = confirmed this was good practice. If you use two shop vacs (one blowing = into the next) you will generate sufficient pressure to both hear and = feel any leaks from inside  and outside the cabin. It is also = important to have someone on the outside listen and feel for leaks as = well. Prop the gear doors open and have the outside person stick his = head in each gear well. Be sure to remove the wedge before doing any = flying.

You should be able to hear the = controller motor run when you change the cabin altitude setting to = insure it is wired properly. The controller is very reliable so it would = be the last thing I would suspect.

With the = controller set 3,000 feet above the airport you should be able to feel = substantial warm air blowing from the vents at pattern altitude and = cruise power. The air should get hot when you change the mixing valve = setting from the coldest to a bit warmer.

With = the the controller set 1,000 feet above the airport the cabin should = climb right up to 4.5 psi as you climb and then remain at 4.5 psi as you = climb further.

Hope the above helps. Send an = email if you want to discuss further. It took me a few tries to really = get it right.

Jack = Morgan
= --Apple-Mail=_D1EF923D-AD03-420C-984E-3C9B5149C1E0--