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<DIV><FONT face=Arial size=2>Someone said this was 'bleeding edge'...just the
batteries are the problem, though--everything else works just fine. In
development, I think I got it from a fairly good source that modeling was a
large factor in finding better batteries--but--memory is the first to
go.... I'm going to be optimistic about this and hope they've got
something better by spring...</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>RS</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=gfowler@raytheon.com href="mailto:gfowler@raytheon.com">Gray E
Fowler</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, November 18, 2005 1:08
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Discussion List
(Batteries)</DIV>
<DIV><BR></DIV><BR><FONT face=sans-serif size=2>Richard</FONT> <BR><BR><FONT
face=sans-serif size=2>In the world of batteries, modelers aint
nuthin'-especially pattern dudes. In the military, battery applications are
critical, but any application like we use them, that is 60 amps for 8 minutes
is a short term disposable application best handled by a chemical-thermal
battery. Military drives such battery technology and it probably is what the
pattern flyers are gloming off of, but the batteries croak simply cuz they are
pushed too hard. If the military or anyone else IS driving the technology, do
you not think that the battery suppliers would pass on such info as your cool
down/heat discharge process to keep pattern dudes from frying their expensive
batteries?</FONT> <BR><BR><FONT face=sans-serif size=2>My point is that this
technology will not be ready for the average pattern flyer for quite some
time(5 years) if ever.</FONT> <BR><BR><FONT face=sans-serif size=2>Good
luck, it is good to hear honesty about these batteries. Most people flying
them dodge life cycle questions -"all so new-dont know yet" which reminds me
of a Rodney Dangerfield joke.......</FONT> <BR><BR><FONT face=sans-serif
size=2>I grew up in a tough neighborhood.......a guy came up to me and my
friends once and asked us "how long does it take to get to the subway from
here" our response was...."dont know....no one's ever made it yet".-tough
neighborhood.</FONT> <BR><FONT face=sans-serif size=2><BR><BR><BR>Gray
Fowler<BR>Principal Chemical Engineer<BR>Composites Engineering</FONT>
<BR><BR><BR>
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<TD width="40%"><FONT face=sans-serif size=1><B>"Richard Strickland"
<richard.s@allied-callaway.com></B> </FONT><BR><FONT
face=sans-serif size=1>Sent by: discussion-request@nsrca.org</FONT>
<P><FONT face=sans-serif size=1>11/18/2005 11:58 AM</FONT>
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<DIV align=center><FONT face=sans-serif size=1>Please respond
to<BR>discussion@nsrca.org</FONT></DIV></TR></TBODY></TABLE><BR></P>
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<DIV align=right><FONT face=sans-serif size=1>To</FONT></DIV>
<TD><FONT face=sans-serif
size=1><discussion@nsrca.org></FONT>
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<DIV align=right><FONT face=sans-serif size=1>cc</FONT></DIV>
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<DIV align=right><FONT face=sans-serif size=1>Subject</FONT></DIV>
<TD><FONT face=sans-serif size=1>Re: Discussion List
(Batteries)</FONT></TR></TBODY></TABLE><BR>
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<TD></TR></TBODY></TABLE><BR></TR></TBODY></TABLE><BR><BR><BR><FONT face=Arial
size=2>Gray, Dean,</FONT> <BR><FONT size=3> </FONT> <BR><FONT face=Arial
size=2>While my experience wasn't the greatest--it really wasn't all that bad
once we had the bugs worked out. BTW, it was a Hacker system like
Jason's.</FONT> <BR><FONT face=Arial size=2>One of the issues was to determine
how cool the batteries needed to be before putting them back on charge;
another was to make sure you were not over or under charging. Another
was to make sure they were balanced. But for me it came down to weight
and longevity. Contrary to where your information is coming from, my
understanding is that modeling IS driving this battery segment along with the
military. I'm reasonably confident there will be significant
breakthroughs like that nano-tech unit(Toshiba or some other heavy-hitter like
that) posted earlier this year that will impact the market fairly shortly.
The 3200s were under-sized, but 4000s would be also. The motors
would peak out at 67-69 amps on application of full throttle and back down to
the 63-65 range. This system worked well, but we were too close to the
edge to lose any capacity and complete an FAI flight. Temps started with
a 40-50 degree rise when we started using them in the upper 70s and 80s and
the same and a little more as ambient got warmer. They got too hot.
We also tend to fly out.</FONT> <BR><FONT size=3> </FONT> <BR><FONT
face=Arial size=2>Realistically, if to get decent mileage out of these things
and have to stay close to 10C; then you've got to have at least 6000s+ and
keep the weight down. I know zip about batteries, except how to design
conveyor systems for them, but they almost need to act like a capacitor--very
high charge, discharge rates, and unlimited cycles with no damage. I
can't imagine there aren't MANY folks working on that concept.</FONT>
<BR><FONT size=3> </FONT> <BR><FONT face=Arial size=2>Of course there are
other alternatives--lighter and/or smaller airframes, different motor, ESC,
prop combinations--but if you want unlimited vertical with 11 lbs--then
your're going to draw 55-70 amps.</FONT> <BR><FONT size=3> </FONT>
<BR><FONT face=Arial size=2>Richard</FONT> <BR><FONT size=3>----- Original
Message ----- </FONT><BR><FONT size=3><B>From:</B> </FONT><A
href="mailto:gfowler@raytheon.com"><FONT color=blue size=3><U>Gray E
Fowler</U></FONT></A><FONT size=3> </FONT><BR><FONT size=3><B>To:</B>
</FONT><A href="mailto:discussion@nsrca.org"><FONT color=blue
size=3><U>discussion@nsrca.org</U></FONT></A><FONT size=3> </FONT><BR><FONT
size=3><B>Sent:</B> Friday, November 18, 2005 10:57 AM</FONT> <BR><FONT
size=3><B>Subject:</B> Re: Discussion List (Batteries)</FONT> <BR><BR><FONT
face=sans-serif size=2><BR>Richard</FONT><FONT size=3> <BR></FONT><FONT
face=sans-serif size=2><BR>I am not a battery expert, but like everyone else
on the list that does not stop me from having an opinion about
batteries.</FONT><FONT size=3> </FONT><FONT face=sans-serif size=2><BR>First,
electric airplanes do not exactly drive the battery market,......even if 50%
of the FAI finalists use them. No other applications <BR>that I am aware of
uses these batteries in the manner that we attempt, which is that massive
current draw. What electric planes do <BR>to batteries is damaging, as
demonstrated by your 25 flights. </FONT><FONT size=3> </FONT><FONT
face=sans-serif size=2><BR>I would not expect the battery market to develop a
battery capable of long life and extreme current draw since no one else uses
<BR>batteries in such a manner.</FONT><FONT size=3> <BR></FONT><FONT
face=sans-serif size=2><BR>Invest in bottle of Windex, clean the oil.
</FONT><FONT size=3><BR><BR><BR></FONT><FONT size=2><TT><BR>In fairness to the
manufacturers, I don't think they really understood that<BR>guys potentially
would go out and fly 50+ flights per week. When I finally<BR>got all my
infrastructure charging act together and made time to<BR>practice--which
wasn't all that much, I still was clicking along at a 35<BR>flight/week pace
right up to our first contest in mid June. As you may<BR>recall, I was
using 20C 3200s on a shared cost beta program. At 11 lbs.,<BR>the
airplanes were gobbling up 63-68 amps at times and significantly heated<BR>the
batteries and shortened their lives. The manufacturer came out
with<BR>some 15C 4000s--but there was still the problem of amp draw and heat.
The<BR>consensus at that point is the batteries aren't very happy at
much over 10C.<BR>The problem I had/have is anything over the smaller
batteries was going to<BR>blow the weight limit--plus, as more information was
coming out from some of<BR>the top guys that they were getting around 50-60
flights on the larger<BR>packs. Since I'm not a top dog, I would pretty
much have to foot the entire<BR>bill to switch to the larger units. As
it appeared to me--the batteries<BR>just aren't quite up to the task for the
average guy--so I made an interim<BR>decision to go back to IC for the rest of
the season--hoping the battery<BR>guys would come up with something more
acceptable for '06.<BR><BR>That didn't pan out very well either, so I was
effectively out for the<BR>season. (Lots of other contributing factors
also) What I told the battery<BR>manufacturer was what a guy really
needs is five sets of batteries(with the<BR>then current stuff) and immediate
service for turnaround. Have three sets<BR>for flying and one or two
sets traveling to/from.<BR><BR>I'm sold on electric--particularly for a guy
with limited practice time. I<BR>could go on and
on....<BR><BR>Richard</TT></FONT><FONT size=3> </FONT><FONT face=sans-serif
size=2><BR><BR><BR><BR>Gray Fowler<BR>Principal Chemical
Engineer<BR>Composites Engineering</FONT> <BR></BLOCKQUOTE></BODY></HTML>