Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Mon, 07 Jun 2004 23:59:31 -0400 Message-ID: X-Original-Return-Path: Received: from sccrmhc13.comcast.net ([204.127.202.64] verified) by logan.com (CommuniGate Pro SMTP 4.2b5) with ESMTP id 143658 for lml@lancaironline.net; Mon, 07 Jun 2004 22:39:34 -0400 Received: from cc1860069a (pcp09040864pcs.rocsth01.mi.comcast.net[69.244.182.42]) by comcast.net (sccrmhc13) with SMTP id <20040608023900016000gus2e>; Tue, 8 Jun 2004 02:39:00 +0000 X-Original-Message-ID: <03ef01c44d01$5cf0af80$2ab6f445@rocsth01.mi.comcast.net> From: X-Original-To: "Lancair Mailing List" References: Subject: Re: Safety X-Original-Date: Mon, 7 Jun 2004 22:36:06 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_03E8_01C44CDF.D24D0F20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_03E8_01C44CDF.D24D0F20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I read Gary Casey's message about safety and aircraft improvements with = interest. I'm a mechanical engineer in the automotive world, but since = I was born with my mother's ability to put together a semi-coherent = sentence, I was drafted into Marketing (horrors!). Anyway, when I was a = practicing engineer, I was pretty sharp. Sharp enough to think that = most of Gary's improvement suggestions are best left on the idea shelf = for the factory to pick through. Speaking as a 360 builder/flyer, I think the best thing we can do is = build these planes to the plans. Then get fresh eyes to look over our = shoulders. Then get a test pilot to make the first flight and train us = into the airplane. Then fly within our training (and the plane's) = limits. I thought maintenance went without saying, but evidently that = must in fact be said. If you go adding things like geared rudder pedals = to backstop an egregious error elsewhere, where's the sense in that? = That rudder cable is not going to break no matter how hard you apply the = brakes. But it will come off the firewall attach if you didn't fasten = it properly or didn't swage the end properly. Or if you cut it part way = through while fixing something else. Pay attention and follow the = manual carefully. On the other hand, your time consuming gear system = adds weight, friction, lots of time, and new failure modes most likely = far scarier than what it was intended to solve. =20 Likewise, don't go adding extra bids, especially of a dissimilar = material like unidirectional carbon, unless you are a structural = engineer and have modeled the structure and your contemplated change. = We've talked about this one before. Stiffening one area can chase loads = and failures to unexpected places. Don't mess with a design that has = demonstrated itself to be successful. Sure, if your test flight shows = you've got a heavy wing, fix it with one of the usual fixes (small flap = adjustment for instance). Learn what your plane does at the stall and = then stay away from that. Count yourself lucky if the stall = characteristics don't frighten you. These aren't training airplanes. =20 It would be different if the design was brand new and untested. Then, = maybe your individual expertise may be substantial when compared to the = body of knowledge and experience manifest in the flying airplane = population. But that's not the case now, I would suggest. Not because = your abilities are diminished, but because hundreds of airplanes and a = decade plus of experience and successful performance say you'll be hard = pressed to improve on it. It's far more likely you'll create new and = nasty problems. On the other hand, do serve up your suggestions to the factory. They = are in the best position to determine value and could incorporate them = into a new model, if the ideas are really worthy. I would not want to = conclude that we can't learn regarding the design, but leave the = modifications to the few people who really know what they are doing = (that's not us). Rather, we should spend our time building well and = flying well. That's time well spent. By the way, obviously = non-structural, non-aerodynamic changes are fine. If you aren't sure = you know the difference vs. changes that affect aerodynamics or the = structure's performance (or any other aspect of function like fuel = delivery), just stick to the plans. =20 Best, Ed de Chazal ------=_NextPart_000_03E8_01C44CDF.D24D0F20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I read Gary Casey's = message about=20 safety and aircraft improvements with interest.  I'm a mechanical = engineer=20 in the automotive world, but since I was born with my mother's ability = to put=20 together a semi-coherent sentence, I was drafted into Marketing=20 (horrors!).  Anyway, when I was a practicing engineer, I was pretty = sharp.  Sharp enough to think that most of Gary's improvement = suggestions=20 are best left on the idea shelf for the factory to pick = through.
 
Speaking as a 360=20 builder/flyer, I think the best thing we can do is build these = planes to=20 the plans.  Then get fresh eyes to look over our shoulders.  = Then get=20 a test pilot to make the first flight and train us into the = airplane.  Then=20 fly within our training (and the plane's) limits.  I thought = maintenance=20 went without saying, but evidently that must in fact be said.  If = you go=20 adding things like geared rudder pedals to backstop an egregious error=20 elsewhere, where's the sense in that?  That rudder cable is not = going to=20 break no matter how hard you apply the brakes.  But it will come = off the=20 firewall attach if you didn't fasten it properly or didn't swage the end = properly.  Or if you cut it part way through while fixing something = else.  Pay attention and follow the manual carefully.  On the = other=20 hand, your time consuming gear system adds weight, friction, lots of = time, and=20 new failure modes most likely far scarier than what it was intended to=20 solve. 
 
Likewise, don't go = adding extra bids,=20 especially of a dissimilar material like unidirectional carbon, unless = you are a=20 structural engineer and have modeled the structure and your contemplated = change.  We've talked about this one before.  Stiffening one = area can=20 chase loads and failures to unexpected places.  Don't mess with a = design=20 that has demonstrated itself to be successful.  Sure, if your test = flight=20 shows you've got a heavy wing, fix it with one of the usual fixes (small = flap=20 adjustment for instance).  Learn what your plane does at the stall = and then=20 stay away from that.  Count yourself lucky if the stall = characteristics=20 don't frighten you.  These aren't training airplanes.  =
 
It would be different = if the design=20 was brand new and untested.  Then, maybe your individual = expertise may=20 be substantial when compared to the body of knowledge and experience = manifest in=20 the flying airplane population.  But that's not the case now, I = would=20 suggest.  Not because your abilities are diminished, but because = hundreds=20 of airplanes and a decade plus of experience and successful performance = say=20 you'll be hard pressed to improve on it.  It's far more likely = you'll=20 create new and nasty problems.
 
On the other hand, do = serve up your=20 suggestions to the factory.  They are in the best position to = determine=20 value and could incorporate them into a new model, if the ideas are = really=20 worthy.  I would not want to conclude that we can't learn regarding = the=20 design, but leave the modifications to the few people who really know = what they=20 are doing (that's not us).  Rather, we should spend our time = building well=20 and flying well.  That's time well spent.  By the way, = obviously=20 non-structural, non-aerodynamic changes are fine.  If you aren't = sure=20 you know the difference vs. changes that affect aerodynamics or the = structure's performance (or any other aspect of function like fuel = delivery),=20 just stick to the plans. 
 
Best,
Ed de=20 Chazal
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