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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=blue><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>When I initially started flying electrics, I used to leave them running at a low idle anytime they were plugged in….pretty obvious indicator of the condition of armed / not armed. I stopped doing this because I felt the likelihood of a problem was greater from bumping the throttle stick when at idle in comparison to bumping the throttle stick with a kill switch engaged.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dave<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> nsrca-discussion-bounces@lists.nsrca.org [mailto:nsrca-discussion-bounces@lists.nsrca.org] <b>On Behalf Of </b>J N Hiller<br><b>Sent:</b> Monday, February 13, 2012 12:14 PM<br><b>To:</b> General pattern discussion<br><b>Subject:</b> Re: [NSRCA-discussion] Arming Switch<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'>I don't fly electric in competition (yet) but I setup the TX the same as my glow airplanes using the throttle cut function, which disables the stick on my SD-10G, preventing accidentally bumping it and energizing the motor. Since I'm BESC the airplane is restrained when plugging in the battery and I still turn on the TX first, mostly out of habit. <o:p></o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'> <o:p></o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'>After landing there are usually bystanders gathering around asking questions and I explain that I need to unplug the battery to be safe before engaging in Q&A. I guess I just don't trust it any more than a still running motor.<o:p></o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'><o:p> </o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'>In a competition airplane I would use an arming plug as some of you already do.<o:p></o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'>Jim<o:p></o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'><o:p> </o:p></span></span></p><p class=MsoNormal><span class=EmailStyle20><span style='font-size:10.0pt'><o:p> </o:p></span></span></p><p class=MsoNormal style='margin-left:.5in'><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black'>-----Original Message-----<br><b>From:</b> <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a> <a href="mailto:[mailto:nsrca-discussion-bounces@lists.nsrca.org]">[mailto:nsrca-discussion-bounces@lists.nsrca.org]</a><b>On Behalf Of </b>Peter Vogel<br><b>Sent:</b> Monday, February 13, 2012 7:31 AM<br><b>To:</b> General pattern discussion<br><b>Cc:</b> General pattern discussion<br><b>Subject:</b> Re: [NSRCA-discussion] Arming Switch</span><o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'><span style='color:black'>From the accidents I've seen or heard of, the issue is not a failure before takeoff, but rather a failure after landing (ESC already armed) or a pilot mishap that results in an unintentional bump of the throttle lever (neck strap, coat, etc)</span><o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'><span style='color:black'>Peter+<br><br>Sent from my iPhone4S</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in'><span style='color:black'><br>On Feb 13, 2012, at 7:18 AM, Bob Richards <<a href="mailto:bob@toprudder.com">bob@toprudder.com</a>> wrote:</span><o:p></o:p></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=530 style='width:397.5pt;margin-left:1.0in'><tr><td valign=top style='padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>Keith,</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>My gut instinct is to agree with you on this, but I have to wonder what is the possibility that there would be a failure mode where the controller could go full throttle without an input from the receiver. For the brushless controllers, the micro in the controller must be working properly for the motor to run - period - since it has to sense the feedback from the motor and operate the outputs in proper phase for the motor to run at all (this would be a different discussion if we were talking about *brushed* controllers). The more likely failure would be that it applies power to one or more motor wires - not pulsed - that would do little more than heat up the motor and burn a winding, but not turn the motor over.</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>Is it possible for the micro think there is a full-throttle input when there isn't? Most controllers that I know of will not arm if it powers up with anything other than a low-throttle signal from the receiver. It has to sense a low-throttle signal that then transitions to something else before it starts the motor turning. Is this a possible failure mode for an ESC - I don't know since I don't know any specifics of the circuitry or firmware programming of ESCs, but I seriously doubt this can happen and if it can, the likelyhood would be extremely low.</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>Of course, not having the battery connected to anything is safe. Safer yet is to just stay at home, but we have to decide what is an acceptable risk.</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>Bob R.</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'> </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'><br><br>--- On <b>Sun, 2/12/12, Keith Black <i><<a href="mailto:tkeithblack@gmail.com">tkeithblack@gmail.com</a>></i></b> wrote:</span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p><div style='mso-element:para-border-div;border:none;border-left:solid #1010FF 1.5pt;padding:0in 0in 0in 4.0pt;margin-left:3.75pt;margin-right:.5in'><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt;border:none;padding:0in'><span style='font-family:"inherit","serif"'><o:p> </o:p></span></p></div><p class=MsoNormal><span style='font-family:"inherit","serif";color:black'>Dave, you're points are correct, but you're not taking into account a malfunction of the speed controller itself. They have been know to malfunction, so the safest approach, as Earl suggests, is to assume that anytime the battery is connected to the controller the motor may go to full throttle. Until you unplug the battery the thing is hot and dangerous regardless of your fail safe or switches on the transmitter. </span><span style='font-family:"inherit","serif"'><o:p></o:p></span></p></td></tr></table><p class=MsoNormal style='mso-margin-top-alt:auto;margin-right:.5in;mso-margin-bottom-alt:auto;margin-left:1.0in'><span style='color:black'>_______________________________________________<br>NSRCA-discussion mailing list<br><a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br><a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a></span><o:p></o:p></p></div></body></html>