X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [65.54.250.79] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 5.0.3) with ESMTP id 864981 for flyrotary@lancaironline.net; Mon, 05 Dec 2005 22:33:52 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.250.79; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 5 Dec 2005 19:33:09 -0800 Message-ID: Received: from 4.171.174.157 by BAY115-DAV7.phx.gbl with DAV; Tue, 06 Dec 2005 03:33:08 +0000 X-Originating-IP: [4.171.174.157] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Intersting flight Date: Mon, 5 Dec 2005 22:33:04 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0170_01C5F9EB.DB7FE530" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 Seal-Send-Time: Mon, 5 Dec 2005 22:33:04 -0500 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 X-OriginalArrivalTime: 06 Dec 2005 03:33:09.0020 (UTC) FILETIME=[C70555C0:01C5FA15] This is a multi-part message in MIME format. ------=_NextPart_000_0170_01C5F9EB.DB7FE530 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al is of course correct about the mathematical chances of failure on the = SYSTEM but I think Ed was referring to the increased chances of the = human involved to deal with the increased complexity. I have seen more = instances of this than I have actual hardware failures. Training on the = system is of vital importance when the system is more complex.=20 Tracy Crook ----- Original Message -----=20 From: al p wick=20 To: Rotary motors in aircraft=20 Sent: Sunday, December 04, 2005 6:36 PM Subject: [FlyRotary] Re: Intersting flight On Sun, 4 Dec 2005 14:32:10 -0500 "Ed Anderson" > writes: > I think the old adage KISS goes a long ways - as you know, it is possible to=20 > decrease reliability (not to mention increasing weight and cost) by = > increasing redundancy pass a certain point - more parts to break. Wow, I TOTALLY disagree with above statement. But note that I define "redundant" as having independent failure odds (same as logical "or" circuit). We always have risk reduction with redundancy. HUGE risk reduction, because you multiply the odds. So 1 circuit has 1 in 100 = odds of failure. 2nd independent circuit jumps the odds to 1 in 10000! = That's why they run two power leads to the ECM on OEM cars. Also multiple = ground leads. Much much safer.=20 Perhaps you allude to cases where you add a second switch, but power = has to flow thru both switches for circuit to operate. In that case, yes, = you actually increase your risk. Those switches would not have independent failure odds. If one fails, so does the other. So they are not = redundant, you just have two items (logically "and" type of circuit). I also don't subscribe to the "single failure point" principal. Yes, = risk often has correlation to single point, but not always. Risk =3D odds = of failure * Effect failed component has on aircraft * odds(inverse) that you will notice failure before flight. > My design is such that you can even shut off the master switch and = the > engine will continue to run. =20 That is good! So you have to really work at it to get it to shut off. Yes! Yes! I'm impressed with your custom gages Ed. It's great seeing = you take action on those items. Good stuff. -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru = 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design = info: = http://www.maddyhome.com/canardpages/pages/alwick/index.html -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0170_01C5F9EB.DB7FE530 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al is of course correct about the mathematical chances of failure = on the=20 SYSTEM but I think Ed was referring to the increased chances of the = human=20 involved to deal with the increased complexity.  I have seen more = instances=20 of this than I have actual hardware failures.  Training on the = system is of=20 vital importance when the system is more complex. 
 
Tracy Crook
----- Original Message -----
From: al p wick
To: Rotary motors in = aircraft
Sent: Sunday, December 04, 2005 = 6:36=20 PM
Subject: [FlyRotary] Re: = Intersting=20 flight


On Sun, 4 Dec 2005 14:32:10 -0500 "Ed = Anderson"
<eanderson@carolina.rr.com&g= t;=20 writes:
> I think the old adage KISS goes a long ways - as you = know, it=20 is
possible to
> decrease reliability (not to mention = increasing=20 weight and cost) by 
> increasing redundancy pass a = certain point=20 - more parts to break.

Wow, I TOTALLY disagree with above = statement.=20 But note that I define
"redundant" as having independent failure = odds (same=20 as logical "or"
circuit). We always have risk reduction with = redundancy.=20 HUGE risk
reduction, because you multiply the odds. So 1 circuit = has 1 in=20 100 odds
of failure. 2nd independent circuit jumps the odds to 1 in = 10000!=20 That's
why they run two power leads to the ECM on OEM cars. Also = multiple=20 ground
leads. Much much safer.

Perhaps you allude to cases = where=20 you add a second switch, but power has
to flow thru both switches = for=20 circuit to operate. In that case, yes, you
actually increase your = risk.=20 Those switches would not have independent
failure odds. If one = fails, so=20 does the other. So they are not redundant,
you just have two items=20 (logically "and" type of circuit).

I also don't subscribe to = the=20 "single failure point" principal. Yes, risk
often has correlation = to single=20 point, but not always. Risk =3D odds of
failure * Effect failed = component has=20 on aircraft * odds(inverse) that
you will notice failure before=20 flight.

> My design is such that you can even shut off the = master=20 switch and  the

> engine will continue to run. =20

That is good! So you have to really work at it to get it to = shut=20 off.
Yes! Yes! I'm impressed with your custom gages Ed. It's great = seeing=20 you
take action on those items. Good stuff.



-al=20 wick
Artificial intelligence in cockpit, Cozy IV powered by stock = Subaru=20 2.5
N9032U 200+ hours on engine/airframe from Portland, = Oregon
Prop=20 construct, Subaru install, Risk assessment, Glass panel design = info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html

--Homepage: =20 http://www.flyrotary.com/
Archi= ve and=20 UnSub:   http://mail.lanca= ironline.net/lists/flyrotary/
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