X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 30 Jan 2010 14:41:20 -0500 Message-ID: X-Original-Return-Path: Received: from asp.reflexion.net ([69.84.129.233] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with SMTP id 4103842 for lml@lancaironline.net; Fri, 29 Jan 2010 14:46:40 -0500 Received-SPF: none receiver=logan.com; client-ip=69.84.129.233; envelope-from=cberland@systems3.net Received: (qmail 621 invoked from network); 29 Jan 2010 19:46:06 -0000 Received: from unknown (HELO mail-cs-03.app.dcb.reflexion.net) (10.84.19.3) by 0 (rfx-qmail) with SMTP; 29 Jan 2010 19:46:06 -0000 Received: by mail-cs-03.app.dcb.reflexion.net (Reflexion email security v6.00.4) with SMTP; Fri, 29 Jan 2010 14:46:06 -0500 (EST) Received: (qmail 3734 invoked from network); 29 Jan 2010 19:46:06 -0000 Received: from unknown (HELO remote.systems3.net) (98.172.79.178) by 0 (rfx-qmail) with (AES128-SHA encrypted) SMTP; 29 Jan 2010 19:46:06 -0000 Received: from S3SBS08SERVER.Systems3.local ([fe80::6077:364b:fa39:c71b]) by S3SBS08SERVER.Systems3.local ([fe80::6077:364b:fa39:c71b%10]) with mapi; Fri, 29 Jan 2010 12:46:05 -0700 From: Craig Berland X-Original-To: Lancair Mailing List X-Original-Date: Fri, 29 Jan 2010 12:46:04 -0700 Subject: [LML] Airspeed sensing switch: Pressurization Thread-Topic: [LML] Airspeed sensing switch: Pressurization Thread-Index: Acqg+DkZAbEa+7NqR6+/MOOtXgodaAAIt7LA X-Original-Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_D7A6B5700A0803448C27264F1F5387363F51576E20S3SBS08SERVER_" MIME-Version: 1.0 --_000_D7A6B5700A0803448C27264F1F5387363F51576E20S3SBS08SERVER_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Do you guys have much luck opening the door before you deflate the door sea= l? I tried to pressurize the cabin with the door seal deflated.....didn't = have much success with 32 InHg manifold pressure. I suspect with the engin= e at idle, it wouldn't be much better. Craig Berland IV-P N7VG Paul pointed out the obvious: a door with even 1 psi behind it is dangero= us. (1 psi times 600 or so? I don't have the measurements) So I do buy the argument that at low throttle settings, and under normal ci= rcumstances, you aren't going to have much residual pressure in the cabin. = But there are lots of possible failure modes here: a) pressure controlle= r malfunction b) pressure controller set way below landing altitude c) exha= ust valve is not operating correctly - not enough cabin exchange rate. The= se may argue for the pressure switch The suggestion I like the best is "check cabin pressure before opening the = door". --_000_D7A6B5700A0803448C27264F1F5387363F51576E20S3SBS08SERVER_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Re: [LML] Re: Airspeed sensing switch: Pressurization

Do you guys have much luck opening the door before you defla= te the door seal?  I tried to pressurize the cabin with the door seal deflated…..didn’t have much success with 32 InHg manifold pressure.  I suspect with the engine at idle, it wouldn’t be muc= h better.

 

Craig Berland

IV-P    N7VG

 

Paul pointed out the obvious:   a door with even 1 psi behind it is dangerous.  (1 psi times 600 or so?   I don't have the measurements)

 

So I do buy the argument that at low throttle settings, and under normal circumstances, you aren't going to have much residual pressure in the cabin.   But there are lots of possible failure modes here: = a) pressure controller malfunction b) pressure controller set way below landin= g altitude c) exhaust valve is not operating correctly - not enough cabin exchange rate.  These may argue for the pressure switch

 

The suggestion I like the best is "check cabin pressure before opening the door".

 

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