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

[Wayne Galligan]

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
> > _______________________________________________
> > NSRCA-discussion mailing list
> > NSRCA-discussion at lists.nsrca.org
> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
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