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<p>I agree with Peter's analysis about the safety issues.</p>
<p>I do not agree that the FAI should have any bearing on what we do
about this rule proposal. It is not enforced at the local level
nor at the Nats. I have heard that the high voltage lipos were
used at the Nats this year fully charged. If the rule is
disregarded and there is not a safety issue, why not increase the
limit to encourage innovation, reduce costs and improve the
longevity of our equipment? See Jeff Worsham's article on rule
proposals in the June 2017 K-Factor.<br>
</p>
<p>We might even demonstrate to the FAI that there is no downside to
a voltage increase. The rule proposal does require that F3A at the
Nats uses the FAI voltage rule in team selection years, just as it
does for the sound rules. Probably won't be checked anyway.</p>
<p>John Gayer</p>
<p>Contest Board District 8 and submitter of the voltage rule
proposal<br>
</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 8/23/2017 5:56 PM, Peter Vogel via
NSRCA-dist7 wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAGBB6kKQW0eN=+p47nfhB=-EHrpf+9feD6xHRW1gmO5V1Un26w@mail.gmail.com">
<div dir="ltr">There was *originally* a safety concern because the
Euro guys argue 42v is enough to kill you (it's a voltage limit,
not a cell count limit, so even the 4.37v lipo cells at 10s are
illegal). But FAI abandoned that concern when they started
allowing 12 and 14s in the helicopter classes (i.e. F3C). I
would argue what Billy Crystal's character said in <i>Running
Scared: </i>"It's not the volts that kill you, it's the
amps". A taser, as an example, delivers about 10,000v and
doesn't kill you. Fundamentally if you let as little as 0.1
amps cross your chest from source to ground you begin to be at
risk of death, at the very least you are going to have serious
difficulty breathing.
<div><br>
</div>
<div>This article reproduces what I was taught in high school: <a
href="https://www.physics.ohio-state.edu/%7Ep616/safety/fatal_current.html"
moz-do-not-send="true">https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html</a></div>
<div><br>
</div>
<div>But that leaves aside the resistance of skin, etc. the
reality is that I = V/R, so the higher the resistance of the
skin the higher the voltage you can handle before allowing
that 0.1 - 0.2 amps across your heart. With dry (not sweaty)
hands the resistance from hand to hand (worst-case scenario of
source to ground going across the chest) is 1M ohms so it
would take about 20kV to get the current needed to kill, but
with sweaty hands it drops to 17,000 ohms and 340V will kill
you, add a wedding ring or a tool with a metal surface you are
gripping tightly and the number could drop to 1000 ohms and
20V will kill, 17V would cause ventricular fibrillation. </div>
<div><br>
</div>
<div>In short, 42V was based on a very elementary "rule of
thumb" analysis and is pretty arbitrary and makes a ton of
assumptions.</div>
<div><br>
</div>
<div>That said, I don't think AMA rules should move to 12S until
FAI rules do...</div>
<div><br>
</div>
<div>Peter+</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Aug 23, 2017 at 4:38 PM, Bill
Polits via NSRCA-dist7 <span dir="ltr"><<a
href="mailto:nsrca-dist7@lists.nsrca.org" target="_blank"
moz-do-not-send="true">nsrca-dist7@lists.nsrca.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Derek K, John G,
<div><br>
</div>
<div>The only objection I have in the past heard with
respect to increasing the electric power system limit to
12S is the issue of safety at the higher voltage (at
least it's my impression that to some degree, safety was
the reason for the original limit). I have no opinion
either way, but just wanted to comment that it seems to
me that a discussion of the matter of safety would be
appropriate to include in the rule change proposal.</div>
<div><br>
</div>
<div>Best regards,</div>
<div><br>
</div>
<div>Bill Polits</div>
<div>NSCRA 4445</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Aug 22, 2017 at 1:00
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Today's Topics:<br>
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1. Current Rules Proposals (Derek Koopowitz)<br>
<br>
<br>
------------------------------<wbr>------------------------------<wbr>----------<br>
<br>
Message: 1<br>
Date: Tue, 22 Aug 2017 10:45:11 -0700<br>
From: Derek Koopowitz <<a
href="mailto:derekkoopowitz@comcast.net"
target="_blank" moz-do-not-send="true">derekkoopowitz@comcast.net</a>><br>
To: <<a href="mailto:nsrca-dist7@lists.nsrca.org"
target="_blank" moz-do-not-send="true">nsrca-dist7@lists.nsrca.org</a>><br>
Subject: [NSRCA-dist7] Current Rules Proposals<br>
Message-ID: <<a
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<br>
<br>
<br>
<br>
<br>
<br>
<br>
Hey everyone,<br>
<br>
<br>
<br>
It is time for me to vote on the rules proposals
that are before the contest board ? I would like
your input on these please. You can view the
current proposals here:<br>
<br>
<br>
<br>
<a
href="http://www.modelaircraft.org/events/ruleproposals/rcaero.aspx"
rel="noreferrer" target="_blank"
moz-do-not-send="true">http://www.modelaircraft.org/e<wbr>vents/ruleproposals/rcaero.asp<wbr>x</a><br>
<br>
<br>
<br>
The cross proposals that were accepted to move on to
the final vote can be seen here:<br>
<br>
<br>
<br>
<a
href="http://www.modelaircraft.org/events/ruleproposals.aspx#2018-2019"
rel="noreferrer" target="_blank"
moz-do-not-send="true">http://www.modelaircraft.org/e<wbr>vents/ruleproposals.aspx#2018-<wbr>2019</a><br>
<br>
<br>
<br>
I?d like your input by early September please. All
votes need to be sent to the AMA by 9/15.<br>
<br>
<br>
<br>
Thanks!<br>
<br>
-Derek<br>
<br>
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<div class="gmail_signature" data-smartmail="gmail_signature">
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<div>
<div dir="ltr">
<div>Director, Fixed Wing Flight Training</div>
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Aeronautics District X</div>
<div>Treasurer, National Society of Radio Control
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