X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 03 Mar 2014 14:46:40 -0500 Message-ID: X-Original-Return-Path: Received: from mail-qa0-f48.google.com ([209.85.216.48] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6758013 for lml@lancaironline.net; Mon, 03 Mar 2014 14:45:50 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.216.48; envelope-from=pjdmiller@gmail.com Received: by mail-qa0-f48.google.com with SMTP id m5so3297241qaj.35 for ; Mon, 03 Mar 2014 11:45:14 -0800 (PST) X-Received: by 10.140.30.230 with SMTP id d93mr25131025qgd.51.1393875914487; Mon, 03 Mar 2014 11:45:14 -0800 (PST) X-Original-Return-Path: Received: from [192.168.2.15] (bas1-stjean93-2925320459.dsl.bell.ca. [174.92.217.11]) by mx.google.com with ESMTPSA id 110sm16808656qgv.19.2014.03.03.11.45.13 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 03 Mar 2014 11:45:14 -0800 (PST) From: Paul Miller Content-Type: multipart/alternative; boundary="Apple-Mail=_1A356872-8C7D-4ADE-8E83-750FF3CA742F" X-Original-Message-Id: <5571CADC-DEB3-4FF5-8BE6-FE189E87A758@gmail.com> Mime-Version: 1.0 (Mac OS X Mail 6.6 \(1510\)) Subject: Re: [LML] Canopy Latch modeling X-Original-Date: Mon, 3 Mar 2014 14:45:13 -0500 References: X-Original-To: "Lancair Mailing List" In-Reply-To: X-Mailer: Apple Mail (2.1510) --Apple-Mail=_1A356872-8C7D-4ADE-8E83-750FF3CA742F Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii My belief is that the canopy itself is an easy device to model. It is = solid, hinged at one point and has a huge surface area. The stories = about not being able to close or open the canopy indicate massive forces = at equilibrium for those that did not move. the gas springs are minor = players with a small lever effect compared to 120k and 310HP at play on = the canopy. I ignore the tail since it is after the canopy and is a = separate analysis and does not affect the canopy forces. If one could simply determine the characteristics of the canopy with = airspeed and AOA, then you have 90% of the answers. I think it is a = pretty simple exercise. The "your plane, your life" stuff has nothing to do with trying to = understand the physics involved although it makes for an exciting read. Paul =20 Probably not true. The canopy system includes the gas springs which = hold it open on the ground, and the spring constant and damping = coefficient of those gas springs are largely unknown, variable, and thus = difficult to model. =20= --Apple-Mail=_1A356872-8C7D-4ADE-8E83-750FF3CA742F Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii

My belief is that the canopy itself is an easy device to = model. It is solid, hinged at one point and has a huge surface = area. The stories about not being able to close or open the canopy = indicate massive forces at equilibrium for those that did not move. = the gas springs are minor players with a small lever effect = compared to 120k and 310HP at play on the canopy. I ignore the = tail since it is after the canopy and is a separate analysis and does = not affect the canopy forces.

If one could simply determine the = characteristics of the canopy with airspeed and AOA, then you have 90% = of the answers. I think it is a pretty simple exercise.

The "your plane, = your life" stuff has nothing to do with trying to understand the physics = involved although it makes for an exciting read.

Paul

Probably not true. The canopy system = includes the gas springs which hold it open on the ground, and the = spring constant and damping coefficient of those gas springs are largely = unknown, variable, and thus difficult to = model.

= --Apple-Mail=_1A356872-8C7D-4ADE-8E83-750FF3CA742F--