X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 05 Aug 2011 20:44:24 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-mealy.atl.sa.earthlink.net ([209.86.89.69] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5083266 for lml@lancaironline.net; Fri, 05 Aug 2011 15:56:26 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.69; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=nc/PjurIqOqos3ABhblGaR58qfu/5t1mbEfLavtoLZB/ceiSXpv12sYAnbA6ODNX; 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 [64.223.163.164] (helo=[192.168.1.24]) by elasmtp-mealy.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1QpQUo-0003Yl-Pl for lml@lancaironline.net; Fri, 05 Aug 2011 15:55:51 -0400 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-321--740498505 Subject: Re: [LML] Re: Fw: Re: Re-doing my panel - carefully thinking through failures X-Original-Date: Fri, 5 Aug 2011 15:55:50 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <5FD81AB5-F0F9-4903-B107-D56AAF79FF88@earthlink.net> X-Mailer: Apple Mail (2.1084) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940e0e682dbb2c872e20c2402fbee38962f350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 64.223.163.164 --Apple-Mail-321--740498505 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 At the risk of topic drift.....I put in those big fat diodes to my = essential bus also. Since them I'm wondering if there's a failure mode on one bus that = crosses the diodes and takes out the other bus. Colyn On Aug 5, 2011, at 10:37 AM, Bill Harrelson wrote: > Hi Fred, > =20 > I like your simplified electrical diagram. I reached almost exactly = the same solution in designing the power grid for our IV except I have 3 = alternators and 3 batteries. Other than that...very similar, big Schotky = diodes feeding the essential bus from 3 independent electrical systems = and the avionics bus powered by two systems, both diode isolated and = able to crosstie to the third. I also have iron gyros, and round = airspeed and altimeter backup instruments. I am no longer young but I = have managed to retain my stupidity. I=92ve not yet achieved the level = of intelligence and maturity that you have as I still have aspirations = for trans Pacific (and worse, trans Antarctic) flights. Maybe I=92ll see = you in OZ one day. > =20 > Bill Harrelson > N5ZQ 320 1,950 hrs > N6ZQ IV under construction > =20 > =20 > =20 > From: Frederick Moreno > Sent: Thursday, August 04, 2011 9:30 AM > To: lml@lancaironline.net > Subject: [LML] Fw: Re: Re-doing my panel - carefully thinking through = failures > =20 > =20 > Brent has written much on this topic including "In my "Glazed and = Confused" presentation on "Glass Cockpits" I say that flying an aircraft = with a non-certified, non TSO'ed glass standby (Dynon et al) is like = jumping out of an airplane with only your main parachute and your = standby plan is the fact you are wearing real soft socks." > =20 > I concur.=20 > =20 > When I was young and stupid (not long ago) I had thoughts of long = overwater (think trans-Pacific) flights. I also have experience with = failure modes assessment analysis (FMEA) which frequently shows up = failure modes easily over looked. After reviewing various electrical = and instrument configurations I arrived at a system design which is = shown in simplified form in the attached sketch. It consists of two = alternators, two batteries, four busses, and a lot of opportunities for = cross tie. I use dual Chelton screens, with PFD off the essential buss = (many sources of power), the MFD off of the avionics bus (which has many = sources of power), and back up electric attitude indicator (on = essential buss), turn and bank (essential buss) and air speed and = altitude indicators. > =20 > You show me the failure and I can show you the automated or manual = work around. And critical stuff is all double protected with circuit = breakers and surge arresters (not shown). > =20 > But even this diagram is not as safe as it could be. What about = something simple like: a battery relay decides to go flotch? (One = already has done so.) That causes a main bus to go south forcing you to = a cross tie solution, not ideal. So not shown are by-pass switches and = fuses around the relay solenoids I added "just in case" to provide = redundancy on all supply routes. > =20 > I have a mechanical and electrical fuel pump. And I have an = electronic ignition and a magneto. > =20 > Two of everything, independent power modes, independent pathways, = cross connects, multiple layers of electrical spike and surge protection = and independent and different principles of gyroscopic display and = electrical power supply. Now one begins to achieve realistically (and = defensible) high levels of reliability. =20 > =20 > If I could only achieve the same with the pilot. > =20 > Fred Moreno > =20 >=20 >=20 > =20 > =20 >=20 > -- > For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html --Apple-Mail-321--740498505 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 At the risk of topic drift.....I put in those big = fat diodes to my essential bus also.
Since them I'm wondering if = there's a failure mode on one bus that crosses the diodes and takes out = the other bus.

Colyn

On = Aug 5, 2011, at 10:37 AM, Bill Harrelson wrote:

Hi Fred,
 
I like = your simplified electrical diagram. I reached almost exactly the same = solution in designing the power grid for our IV except I have 3 = alternators and 3 batteries. Other than that...very similar, big Schotky = diodes feeding the essential bus from 3 independent electrical systems = and the avionics bus powered by two systems, both diode isolated and = able to crosstie to the third. I also have iron gyros, and round = airspeed and altimeter backup instruments. I am no longer young but I = have managed to retain my stupidity. I=92ve not yet achieved the level = of intelligence and maturity that you have as I still have aspirations = for trans Pacific (and worse, trans Antarctic) flights. Maybe I=92ll see = you in OZ one day.
 
Bill = Harrelson
N5ZQ 320 1,950 hrs
N6ZQ  IV under = construction
 
 
 
Sent: Thursday, August 04, 2011 = 9:30 AM
= Subject: [LML] = Fw: Re: Re-doing my panel - carefully thinking through = failures
 
 
Brent has = written much on this topic including "In my "Glazed and Confused" = presentation on "Glass Cockpits" I say that flying an aircraft with a = non-certified, non TSO'ed glass standby (Dynon et al) is like jumping = out of an airplane with only your main parachute and your standby plan = is the fact you are wearing real soft = socks."
 
I = concur. 
 
When I was young and stupid = (not long ago) I had thoughts of long overwater (think trans-Pacific) = flights.  I also have experience with failure modes assessment = analysis (FMEA) which frequently shows up failure modes easily over = looked.  After reviewing various electrical and instrument = configurations I arrived at a system design which is shown in simplified = form in the attached sketch.  It consists of two alternators, two = batteries, four busses, and a lot of opportunities for cross tie.  = I use dual Chelton screens, with PFD off the essential buss (many = sources of power), the MFD off of the avionics bus (which has many = sources of power), and back up electric attitude  indicator (on = essential buss), turn and bank (essential buss) and air speed and = altitude indicators.
 
You show me the failure = and I can show you the automated or manual work around.  And = critical stuff is all double protected with circuit breakers and surge = arresters (not shown).
 
But even this = diagram is not as safe as it could be.  What about something = simple like: a battery relay decides to go flotch?  (One already = has done so.)  That causes a main bus to go south forcing you to a = cross tie solution, not ideal.  So not shown are by-pass switches = and fuses around the relay solenoids I added "just in case" to provide = redundancy on all supply routes.
 
I have a = mechanical and electrical fuel pump.  And I have an electronic = ignition and a magneto.
 
Two of everything, = independent power modes, independent pathways, cross connects, multiple = layers of electrical spike and surge protection and independent and = different principles of gyroscopic display and  electrical power = supply.  Now one begins to achieve realistically (and defensible) = high levels of reliability.  
 
If I = could only achieve the same with the = pilot.
 
Fred = Moreno
 


 
 
=
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For archives and = unsub http://mail.= lancaironline.net:81/lists/lml/List.html

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