Return-Path: Sender: (Marvin Kaye) To: lml Date: Sun, 10 Aug 2003 19:33:17 -0400 Message-ID: X-Original-Return-Path: Received: from tomts25-srv.bellnexxia.net ([209.226.175.188] verified) by logan.com (CommuniGate Pro SMTP 4.1) with ESMTP id 2516561 for lml@lancaironline.net; Sun, 10 Aug 2003 13:07:38 -0400 Received: from a ([67.69.58.77]) by tomts25-srv.bellnexxia.net (InterMail vM.5.01.05.32 201-253-122-126-132-20030307) with SMTP id <20030810170736.MZQB20149.tomts25-srv.bellnexxia.net@a> for ; Sun, 10 Aug 2003 13:07:36 -0400 X-Original-Message-ID: <003301c35f62$e8d4cdc0$163a4543@a> From: "Ian B. Crowe" X-Original-To: "Lancair Mailing List" Subject: Fuel tank testing X-Original-Date: Sun, 10 Aug 2003 13:14:50 -0400 Organization: Corvi Trade Consultants Inc MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 5 to 7 psi translates to a minimum of 720lb/sq ft on every square foot of the wing skin. That is a lot of force trying to burst the tank. I would say that pressure is an accident waiting to happen. Also what other joints have you strained that you cannot see? IMHO 1psi is more than enough to show up any leaks. I used that and found one leak at the rear spar attachment bolts. I also used a home made manometer to measure the pressure. It was of such a length that it would blow out all the water before the applied pressure burst the tank. An interesting feature of the manometer is that it reacted to the barometric pressure rising and falling which made me think I had a leak after I fixed the first leak. It seems obvious to me now but I spent a few days chasing non existent leaks. This point demonstrates the sensitivity of the skin to fairly minor changes in pressure. Incidentally I held my pressure for 36 hours in the final test before I dismantled it. Ian Crowe C-FKRO 360 75 hours