[NSRCA-discussion] AAA NimH batterys to Coke bootle fuel tanks

Sat Jan 28 11:16:05 AKST 2006

Wayne
 Yes I am convinced the hi nitro is causing the plastic to shrink. Good to
hear that 15% has little effect.

Jim Ivey
----- Original Message ----- 
From: "Wayne Galligan" <wgalligan at texasairnet.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Saturday, January 28, 2006 10:24 AM
Subject: Re: [NSRCA-discussion] AAA NimH batterys to Coke bootle fuel tanks

> Jim and all,
>
> So far I have I had excellent service with my Coke bottle fuel tank.  Now
> granted, I am using 15% Cool Power and running an OS 1.40 that sips fuel
and
> others that have experienced tank shrinkage have been using higher nitro
> content and running YS's.  Since the NAT's I have only changed my tank
once.
> It only takes a quick rinse of the bottle with some fuel and you can be
back
> in the air in about 5 minutes. So for the quick weight fix it would OK
even
> if you had to change tanks every day at a contest.
>
> Advantage that I have found with the Coke bottle shape is it keeps the
clunk
> in the fuel better. Since changing from a DuBro tank the engine no longer
> sucks air when low on fuel and a 16.9oz bottle delivers just as much
flying
> time as a 20oz Dubro did because of this.
>
>  As for the 750mil 3A NiMh packs... keep them for your small airplanes and
> not a $2500 airship. I think you'd be better off using Li-Ion or Li-Po's
if
> making weight is an issue.
>
> Wayne Galligan
>
> ----- Original Message ----- 
> From: <jivey61 at bellsouth.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Saturday, January 28, 2006 7:49 AM
> Subject: Re: [NSRCA-discussion] AAA NimH batterys
>
>
> > All.......
> > You are sacrificing safety for weight.....not good. Stick with a good
> > capacity battery and remove the on-off switch and harness this will save
> you
> > 1 oz +.I did this just for Nats for 6 flights......made weight and it is
> > safe.
> > By the way I am still experimenting with coke bottle tanks.These save
> 1-1/2
> > oz versus tettra.  I have a 32 oz bottle filled with fuel in the
shrinking
> > process,for 2 months now. It has shrunk 1/4 inch in diameter.My hopes
are
> > that when it stops shrinking it will be 24-26 fluid oz which works with
> the
> > thirsty DZ. Hope it doesnt leak and I will tell results later.
> >
> > Jim Ivey
> > ----- Original Message ----- 
> > From: "Jerry Budd" <jerry at buddengineering.com>
> > To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> > Sent: Saturday, January 28, 2006 4:02 AM
> > Subject: Re: [NSRCA-discussion] AAA NimH batterys
> >
> >
> > > For the 2002 Nats I switched to a AAA 700 mAh NiMH battery pack to
> > > make weight.  While practicing at the Kokomo field I discovered that
> > > the pack was good for about 1-1/2 flights (don't ask me how I know
> > > that!).
> > >
> > > Fortunately, I got control back (well - partially) after the 1-1/2
> > > downline snap and was able to coax the plane back onto the ground.
> > > Not fun.
> > >
> > > At the post-flight debrief I figured out that the AAA cells simply
> > > had too high of an internal impedance to deliver enough current to
> > > keep the voltage above the receiver/servo cut-off level when all the
> > > servos needed to move at once.  I was using JR 7000 Super Servos for
> > > aileron which went slow/shut off at 4.6V whereas the other JR servos
> > > kept on working down to 4.2V.
> > >
> > > Jerry
> > >
> > >
> > > >Ed is right.  The smaller the cells the higher the internal
resistance.
> > Run
> > > >them down to 20% remaining capacity and put a heavy load, like 5 Amps
> on
> > > >them and read the voltage.  You will probably not like what you see.
> > > >
> > > >Jim O
> > > >
> > > >
> > > >----- Original Message -----
> > > >From: "Ed Alt" <ed_alt at hotmail.com>
> > > >To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> > > >Sent: Thursday, January 26, 2006 3:06 PM
> > > >Subject: Re: [NSRCA-discussion] AAA NimH batterys
> > > >
> > > >
> > > >>  Ed:
> > > >>  You might get disappointing results due to the inherently high
> > internal
> > > >>  resistance of NiMH.  Going with AAA cella and such a low capacity
> > might
> > > >mean
> > > >>  that you don't get as many flights as you expect before a voltage
> test
> > > >under
> > > >>  load dips below an acceptable value.
> > > >>
> > > >>  Ed
> > > >>  ----- Original Message -----
> > > >>  From: "Ed Miller" <edbon85 at charter.net>
> > > >>  To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> > > >>  Sent: Thursday, January 26, 2006 9:05 AM
> > > >>  Subject: [NSRCA-discussion] AAA NimH batterys
> > > >>
> > > >>
> > > >>  > Is anyone using AAA NimH batteries for a RX pack ??. I am
looking
> at
> > > >>  > Batteries America ( EHYOST ) and they seem to have AAA NimH's in
> > 720,
> > > >800
> > > >>  > and 900mah ratings. I currently use their 2/3A 5 cell NimH pack
at
> > > >1100mah
> > > >>  > and a weight of 3.85 ounces complete with the long lead I have
on
> > the
> > > >>  > pack.
> > > >>  > Going to their AAA 5 cell pack looks like I can save about an
> ounce
> > or
> > > >so.
> > > >>  > Mah isn't an issue, I can get in excess of 7 to 8 flights on the
> > 1100mah
> > > >>  > pack I use now before charging so going to 900mah shouldn't be a
> big
> > > >hit.
> > > >>  > Don't suggest Lithium anything as lighter, want to continue to
use
> > my
> > > >>  > Alpha
> > > >>  > 4 charger and am not convinced those new batteries are safe.
> > > >  > > Ed M.
> > >
> > > -- 
> > > ___________
> > > Jerry Budd
> > > Budd Engineering
> > > (661) 722-5669 Voice/Fax
> > > (661) 435-0358 Cell Phone
> > > mailto:jerry at buddengineering.com
> > > http://www.buddengineering.com
> > > _______________________________________________
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> > > NSRCA-discussion at lists.nsrca.org
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> >
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