X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 06 Sep 2013 07:54:24 -0400 Message-ID: X-Original-Return-Path: Received: from col0-omc3-s4.col0.hotmail.com ([65.55.34.142] verified) by logan.com (CommuniGate Pro SMTP 6.0.6) with ESMTP id 6456222 for lml@lancaironline.net; Thu, 05 Sep 2013 20:19:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.34.142; envelope-from=peterpawaviation@hotmail.com Received: from COL129-W69 ([65.55.34.136]) by col0-omc3-s4.col0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Thu, 5 Sep 2013 17:19:18 -0700 X-TMN: [dfnS0amYPbId+jeW4+dr7k1Jm+lPpjUU] X-Originating-Email: [peterpawaviation@hotmail.com] X-Original-Message-ID: X-Original-Return-Path: peterpawaviation@hotmail.com Content-Type: multipart/alternative; boundary="_9ff2b7a2-693f-4e66-8a94-f051989bd7e8_" From: PETER WILLIAMS X-Original-To: Lancair Mailing List Subject: more on IVP pressurization X-Original-Date: Thu, 5 Sep 2013 20:19:18 -0400 Importance: Normal In-Reply-To: References: MIME-Version: 1.0 X-OriginalArrivalTime: 06 Sep 2013 00:19:18.0674 (UTC) FILETIME=[BA3D9F20:01CEAA96] --_9ff2b7a2-693f-4e66-8a94-f051989bd7e8_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable john have you flown the airplane at altitude? after a bunch of work on sealing my 4P i have a 3=2C800' cabin at 17=2C500 with 32" and 2300rpm i have the altitude set at 1=2C000 feet=3B where it should be if i am ret= urning to sea level peter > To: lml@lancaironline.net > Date: Wed=2C 4 Sep 2013 07:42:10 -0400 > From: 2thman1@gmail.com > Subject: [LML] IVP pressurization >=20 > Having trouble getting my pressurization to work effectively. > I did my best to seal the pressure vessel but never got above .25 PSID wi= th 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 memb= rane 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 the= re were a couple of slight improvements to be made mostly in the wire bundl= es through the aft pressure bulkhead and after doing this he declared the v= essel seal very good. =20 >=20 > So we deduced that maybe the shop vac is not as efficient at blowing air = as I thought=2C 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 ves= sel 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 diaph= ragm could be failing=2C etc. I removed the outflow valve yesterday and tr= ied to examine the parts. i lubricated the mandrel that the poppet valve s= lides on with a very small spritz of LPS1 lubricant in case there was stict= ion there. I did notice that with the poppet valve manually moved to the f= urthest closed position the diaphragm still had somewhere around a 1/32" ga= p at the seating perimeters. Should the air pressure in flight fill that d= iaphragm 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? A= m I just setting the pressurization up wrong? Have only been up to 3=2C00= 0 ft elevation airports=2C (KRDM) and lower - most at sea level. >=20 > Thanks for any help. >=20 > John Barrett >=20 > Sent from my iPad > =20 > -- > For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.ht= ml = --_9ff2b7a2-693f-4e66-8a94-f051989bd7e8_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
john

have you = flown the airplane at altitude?
after a bunch of work on sealing my 4P i have a 3=2C800' cab= in at 17=2C500
with 32" and 2300rpm
 =3B i have= the altitude set at 1=2C000 feet=3B where it should be if i am returning t= o sea level

peter=

>=3B To: lm= l@lancaironline.net
>=3B Date: Wed=2C 4 Sep 2013 07:42:10 -0400
>= =3B From: 2thman1@gmail.com
>=3B Subject: [LML] IVP pressurization
= >=3B
>=3B Having trouble getting my pressurization to work effectiv= ely.
>=3B I did my best to seal the pressure vessel but never got abov= e .25 PSID with my 6 horse shop vac. Used both pressure and vacuum to chec= k for leaks. No smoke but used a down feather and then a stethoscope with = tympanic membrane removed. Outflow valve is covered during these tests.>=3B
>=3B After lots of frustration i hired a guy who has built an= d/or pressurized about a dozen IVPs to come take a look. He determined usi= ng 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.
>=3B
>=3B So we deduced= that maybe the shop vac is not as efficient at blowing air as I thought=2C= but my flying experience with the aircraft is that it doesn't do much bett= er than the .25 PSID in flight up to 14.5K ft.
>=3B
>=3B Wonde= ring why there is inadequate pressurization with a good pressure vessel lea= ds 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 co= uld be failing=2C etc. I removed the outflow valve yesterday and tried to = examine the parts. i lubricated the mandrel that the poppet valve slides o= n with a very small spritz of LPS1 lubricant in case there was stiction the= re. 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 th= e seating perimeters. Should the air pressure in flight fill that diaphrag= m to close the gap or does this indicate the valve needs servicing?
>= =3B
>=3B Finally is there a way short of the manual dump switch to ke= ep the system from pressurizing better than what I see by mismanaging the c= ontroller? Am I just setting the pressurization up wrong? Have only been= up to 3=2C000 ft elevation airports=2C (KRDM) and lower - most at sea leve= l.
>=3B
>=3B Thanks for any help.
>=3B
>=3B John Barr= ett
>=3B
>=3B Sent from my iPad
>=3B
>=3B --
>= =3B For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.= html
= --_9ff2b7a2-693f-4e66-8a94-f051989bd7e8_--