X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from elasmtp-junco.atl.sa.earthlink.net ([209.86.89.63] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTP id 6757776 for lml@lancaironline.net; Mon, 03 Mar 2014 13:23:10 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.63; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=qWQhnydZ5Lf5I1nNNIrVbLPdL5/K9980sZzWYpXwEKzOprp9dmIDZK+eMB5lLq1r; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [72.73.84.133] (helo=[192.168.1.24]) by elasmtp-junco.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1WKXVV-0003sx-Ql for lml@lancaironline.net; Mon, 03 Mar 2014 13:22:30 -0500 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: multipart/alternative; boundary=Apple-Mail-79--1048078481 Subject: Re: [LML] Canopy Latch modeling Date: Mon, 3 Mar 2014 13:22:29 -0500 In-Reply-To: To: "Lancair Mailing List" References: Message-Id: X-Mailer: Apple Mail (2.1085) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da94025cf2b3f1075717df9a1a20996e8cee8350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 72.73.84.133 --Apple-Mail-79--1048078481 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii "Your airplane. Your life. Your choice." sorta. it's a fleet problem with outcomes affecting pilots in = the whole fleet....even different Lancair models. We should have a fleet goal (all Lancairs) of getting the = accident rate to something reasonable, then identify the biggest = contributors to the accident rate and go after them. This may involve = taking some actions beyond what it takes to get down to your personal = risk tolerance. Colyn=20 On Mar 3, 2014, at 7:50 AM, frederickemoreno@gmail.com wrote: "We have the talent here to do a 3D model and some wind testing without = the need to fly someone's airplane or do full power taxi tests." =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 Moreover when the canopy opens, you have a separated air flow condition = moderated by the overall aircraft transient angle of attack (it changes = when the canopy swings open and closed) which is exceptionally difficult = to model on a computer without corroborating evidence from wind tunnel = testing.=20 =20 Forecasting effects on tail would be very difficult even with = exceptionally competent computational fluid mechanics software and = computers. And of course, effects triggered by any impulsive = pilot-induced oscillation would be entirely missed. =20 Nope, computer models won't help enough to put solid predictive = capability forward for study.=20 =20 But we do have DATA in the form of accident statistics. John's = analysis shows that even with all the ambiguity in such data, the = accident rate is unacceptably high. =20 Best solution, and probably easiest and by far most effective: a = secondary safety latch.=20 =20 It then becomes a question of details of design and installation. It is = here that John and his supporters have failed to gain traction in the = community and also failed to get feedback from the factory. We need to = know the effect of punching some holes in the canopy arch and mating = structure so latch and catch can be mounted. With that data and some = design review from the community, design improvements would emerge, and = as a group we could stamp out some simple parts, install, and deal with = this problem once and for always. =20 Your airplane. Your life. Your choice. =20 Fred Moreno --Apple-Mail-79--1048078481 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii "Your airplane.  Your life.  Your = choice."

sorta.   it's a fleet = problem with outcomes affecting pilots in the whole fleet....even = different Lancair models.

We should have a fleet goal (all = Lancairs) of getting the accident rate to something reasonable, then = identify the biggest contributors to the accident rate and go after = them.   This may involve taking some actions beyond what it takes = to get down to your personal risk tolerance.

Colyn 

On Mar 3, 2014, at 7:50 AM, frederickemoreno@gmail.com = wrote:

"We have = the talent here to do a 3D model and some wind testing without the need = to fly someone's airplane or do full power taxi = tests."
 
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.
 
Moreover when the canopy opens, you = have a separated air flow condition moderated by the overall aircraft = transient angle of attack (it changes when the canopy swings open and = closed) which is exceptionally difficult to model on a computer without = corroborating evidence from wind tunnel = testing. 
 
Forecasting effects on tail = would be very difficult even with exceptionally competent computational = fluid mechanics software and computers.  And of course, effects = triggered by any impulsive pilot-induced oscillation would be entirely = missed.
 
Nope, computer models won't help = enough to put solid predictive capability forward for = study. 
 
But we do have  DATA in the = form of accident statistics.  John's analysis shows that even with = all the ambiguity in such data, the accident rate is unacceptably = high.
 
Best solution, and probably = easiest and by far most effective: a secondary safety = latch. 
 
It then becomes a question of = details of design and installation.  It is here that John and his = supporters have failed to gain traction in the community and also failed = to get feedback from the factory.   We need to know the effect = of punching some holes in the canopy arch and mating structure so latch = and catch can be mounted.  With that data and some design review = from the community, design improvements would emerge, and as a group we = could stamp out some simple parts, install, and deal with this problem = once and for always.
 
Your airplane.  = Your life.  Your choice.
 
Fred = Moreno
<= /span>

= --Apple-Mail-79--1048078481--