X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 10 Mar 2013 10:11:51 -0400 Message-ID: X-Original-Return-Path: <2thman1@gmail.com> Received: from mail-pb0-f45.google.com ([209.85.160.45] verified) by logan.com (CommuniGate Pro SMTP 6.0.2) with ESMTPS id 6113892 for lml@lancaironline.net; Sun, 10 Mar 2013 03:26:38 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.45; envelope-from=2thman1@gmail.com Received: by mail-pb0-f45.google.com with SMTP id ro8so2655294pbb.18 for ; Sat, 09 Mar 2013 23:26:03 -0800 (PST) X-Received: by 10.68.171.99 with SMTP id at3mr17821177pbc.136.1362900363144; Sat, 09 Mar 2013 23:26:03 -0800 (PST) X-Original-Return-Path: <2thman1@gmail.com> Received: from [192.168.1.131] (c-66-235-58-245.sea.wa.customer.broadstripe.net. [66.235.58.245]) by mx.google.com with ESMTPS id eg1sm14118337pbb.33.2013.03.09.23.26.02 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 09 Mar 2013 23:26:02 -0800 (PST) References: In-Reply-To: Mime-Version: 1.0 (1.0) Content-Type: multipart/alternative; boundary=Apple-Mail-D4DAFFE5-B89B-4907-83B6-B02E3AE6BB5D X-Original-Message-Id: <0B71587B-E758-42D7-B860-707EC7BBF2B5@gmail.com> Content-Transfer-Encoding: 7bit X-Mailer: iPad Mail (10B146) From: John Barrett <2thman1@gmail.com> Subject: Re: [LML] Re: Pressurization X-Original-Date: Sat, 9 Mar 2013 23:26:00 -0800 X-Original-To: Lancair Mailing List --Apple-Mail-D4DAFFE5-B89B-4907-83B6-B02E3AE6BB5D Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Thanks to all for your input on this subject. Am sidetracked with remountin= g the engine that got here a few days ago from Barrett's shop in Tulsa. Wil= l get back to pressurization in a few days. John Sent from my iPad On Mar 9, 2013, at 7:42 AM, Ted Noel wrote: > John, >=20 > Try http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html >=20 > Ted Noel >=20 > On 3/8/2013 8:11 AM, John Barrett wrote: >>=20 >> I didn=E2=80=99t think I=E2=80=99d need help with measurement issues, but= I=E2=80=99m hitting some stone walls. >> =20 >> I have a pocket altimeter I thought I=E2=80=99d use but wonder if it will= have a stop on negative altitude. Also I went online to see how to convert= altitude differential to PSID. Not much luck. The one site I found had co= nversion formulae that don=E2=80=99t seem correct. It lists a correlation 1= =E2=80=9D of mercury to 1,000 feet of altitude and that should be ok. It th= en goes on to list a .49 conversion factor to get from inches of mercury to p= si.=20 >> =20 >> My calculations show that at a service ceiling of FL290 the altitude diff= erence to 10,000 foot cabin alt is 19,000 feet. .49 times this difference i= s about 9.5 PSID. That=E2=80=99s WAY higher than the 5.0 PSI we=E2=80=99re s= upposed to be seeing in the LIVP at FL 290. I had hoped to test to about 6 P= SI. >> =20 >> Short of an altimeter that allows negative readings all the way to someth= ing over 19K and a formula that works, the only other instrument I can think= of is a gauge that reads psi. I found some online that sell for from a cou= ple hundred bucks to $450 or so. They all appeared to be set up for plumbin= g into a pipe system and I don=E2=80=99t know if they would read correctly i= f placed inside the cockpit. >> =20 >> How have you IVP builders out there gone about getting measurements when s= ealing up the pressure vessel? >> =20 >> Thanks, >> =20 >> John Barrett, CEO >> Leading Edge Composites >> PO Box 428 >> Port Hadlock, WA 98339 >> =20 >> www.carbinge.com --Apple-Mail-D4DAFFE5-B89B-4907-83B6-B02E3AE6BB5D Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

Thanks to all for your input on this s= ubject. Am sidetracked with remounting the engine that got here a few d= ays ago from Barrett's shop in Tulsa. Will get back to pressurization i= n a few days.

John

Sent from my iPad

On Mar 9, 2013, at 7:42 AM, Ted Noel <tednoel@cfl.rr.com> wrote:

=20 =20 =20 John,

Try http://www.engineeringtoolbox.com/air= -altitude-pressure-d_462.html

Ted Noel

On 3/8/2013 8:11 AM, John Barrett wrote:

I didn=E2=80=99t think I=E2=80=99d need help w= ith measurement issues, but I=E2=80=99m hitting some stone walls.=

I have a pocket altimeter I thought I=E2=80=99= d use but wonder if it will have a stop on negative altitude. Also= I went online to see how to convert altitude differential to PSID. Not much luck. The one site I found had conversi= on formulae that don=E2=80=99t seem correct. It lists a correla= tion 1=E2=80=9D of mercury to 1,000 feet of altitude and that should be ok. It then goes on to list a .49 conversion factor to get from inches of mercury to psi.

My calculations show that at a service ceiling of FL290 the altitude difference to 10,000 foot cabin alt is 19,000 feet. .49 times this difference is about 9.5 PSID. That=E2=80=99s WAY higher than the 5.0 PSI we=E2=80=99= re supposed to be seeing in the LIVP at FL 290. I had hoped to test to about 6= PSI.

Short of an altimeter that allows negative readings all the way to something over 19K and a formula that works, the only other instrument I can think of is a gauge that reads psi. I found some online that sell for from a couple hundred bucks to $450 or so. They all appeared to be set up for plumbing into a pipe system and I don=E2=80=99t know if= they would read correctly if placed inside the cockpit.

How have you IVP builders out there gone about getting measurements when sealing up the pressure vessel?

Thanks,

John Barrett, CEO

Leading Edge Composites

PO Box 428

Port Hadlock, WA 98339

www.carbinge.com

=20

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