X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from vms044pub.verizon.net ([206.46.252.44] verified) by logan.com (CommuniGate Pro SMTP 5.0.3) with ESMTP id 863489 for flyrotary@lancaironline.net; Mon, 05 Dec 2005 01:26:36 -0500 Received: from [63.24.45.144] ([63.24.49.233]) by vms044.mailsrvcs.net (Sun Java System Messaging Server 6.2-4.02 (built Sep 9 2005)) with ESMTPA id <0IR0008KHHVRCE89@vms044.mailsrvcs.net> for flyrotary@lancaironline.net; Mon, 05 Dec 2005 00:26:23 -0600 (CST) Date: Sun, 04 Dec 2005 22:26:09 -0800 From: Ken Welter Subject: [FlyRotary] Re: Intersting flight In-reply-to: To: "Rotary motors in aircraft" Message-id: MIME-version: 1.0 Content-type: multipart/alternative; boundary="============_-1078358513==_ma============" References: --============_-1078358513==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" >You make an excellent point on the single failure >point. I've been trying to come up with a way to >eliminate the problem, but outside of going to 2 >switches, I'm not sure how to do it. Even with 2 >switches the one for the engine is still a single >failure point for the engine. > >I'm sure there is more than one 'right' way. My choice was 2 >batteries, two contactors, 2 'master' switches. The engine critical >bus is powered directly from both batteries, isolated by Schottky >diodes. The circuits for each set of injectors, and each set of >coils are separate, as is backup for ECU and fuel pumps. These >circuits are protected by fuses. Both masters can be off and the >engine still run. > >Your experience caused me to review my system for single point >weakness. The 2 master switches have separate grounds to the panel >ground bus. There is only one #12 lead from the panel ground bus >back to the copper pipe (which is my main ground lead from batteries >in front to engine in back). It is bolted and soldered at the >ground bus, but fastened to the copper pipe with a sheet metal screw >through a loop connector. I need to review that connection to make >certain that it can not come loose or lose contact. I will also >review the other single point connections on the ground side. I >don't consider a heavy gauge wire a potential single point failure; >but a connection always has to be considered suspect. > >Sharing your experience can result in improved reliability for the >rest us. In my business as commodity trader I have a motto; "take >the loss, but don't lose the lesson". Each time there is an >occurrence such as yours, we need to learn from it. > >Best, > >Al > I have two batteries and two masters switches, I also have a double throw center off ignition switch for the leading and one for the trailing, I also have two fuel pumps with a double pole double throw center off switch for each pump and with this setup I can takeoff and climb out with one ignition system and one fuel pump one the main battery and the other ignition system and fuel pump on the auxiliary battery. With this setup there is no way I can lose power with a single failure point. Ken Welter --============_-1078358513==_ma============ Content-Type: text/html; charset="us-ascii" [FlyRotary] Re: Intersting flight
You make an excellent point on the single failure
point.  I've been trying to come up with a way to
eliminate the problem, but outside of going to 2
switches, I'm not sure how to do it. Even with 2
switches the one for the engine is still a single
failure point for the engine. 
 
I'm sure there is more than one 'right' way.  My choice was 2 batteries, two contactors, 2 'master' switches.  The engine critical bus is powered directly from both batteries, isolated by Schottky diodes.  The circuits for each set of injectors, and each set of coils are separate, as is backup for ECU and fuel pumps.  These circuits are protected by fuses.  Both masters can be off and the engine still run.
 
Your experience caused me to review my system for single point weakness. The 2 master switches have separate grounds to the panel ground bus. There is only one #12 lead from the panel ground bus back to the copper pipe (which is my main ground lead from batteries in front to engine in back).  It is bolted and soldered at the ground bus, but fastened to the copper pipe with a sheet metal screw through a loop connector.  I need to review that connection to make certain that it can not come loose or lose contact.  I will also review the other single point connections on the ground side.  I don't consider a heavy gauge wire a potential single point failure; but a connection always has to be considered suspect.
 
Sharing your experience can result in improved reliability for the rest us.  In my business as commodity trader I have a motto; "take the loss, but don't lose the lesson".  Each time there is an occurrence such as yours, we need to learn from it.
 
Best,
 
Al
 

  I have two batteries and two masters switches, I also have a double throw center off ignition switch for the leading and one for the trailing, I also have two fuel pumps with a double pole double throw center off  switch for each pump and with this setup I can takeoff and climb out with one ignition system and one fuel pump one the main battery and the other ignition system and fuel pump on the auxiliary battery.
  With this setup there is no way I can lose power with a single failure point.
  Ken Welter
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