[NSRCA-discussion] [NSRCA-discussion ]Coke bottle tanks

Mon Jan 30 09:11:29 AKST 2006

Yep.  In the '50's We were encouraging our wives to shampoo their hair twice 
a day, or more!  The bottles worked great.  Much heavier walls than the 
tanks we use today.  Bill Glaze
----- Original Message ----- 
From: "Stuart Chale" <schale at optonline.net>
To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
Sent: Sunday, January 29, 2006 9:42 AM
Subject: Re: [NSRCA-discussion] [NSRCA-discussion ]Coke bottle tanks


>I would suspect that a coke bottle tank as long as the stopper is secure
> would be very durable.  After all it has to stand up to pressurized water 
> in
> it no matte how hard you shake it :)
>
> Way back when I was running round shampoo bottles in YS 60 pumped pattern
> planes.  In fact I still have an Atlanta with one in it.  The ones I used
> were a long cylinder shape which allowed it to fit right over the CG in
> those relatively narrow fuses.  Except for the flat bottom the cylinder
> shape was perfect for pressurization.  Just think of the propane truck's
> tank shape.
>
> A comment on Kraft tanks:
> They are seamed or at least they used to be and a pressurized system will
> split them quite easily.  Luckily I learned this on a test stand and not 
> in
> a model.
>
> Stuart
>
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ed Miller
> Sent: Saturday, January 28, 2006 10:10 AM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] AAA NimH batterys
>
> Making weight isn't a problem. My EMC2 currently weighs 4815 grams. Just
> looking for that elusive 4799 marker and keep plane durable and 
> maintenance
> free. Tank is already light, Kraft 16oz at 57 grams and don't want the
> possibility of filling the fuse with fuel in the event the coke bottle 
> tank
> leaks.  I'll leave my 5 cell, 2/3A, 1100mah NimH in place. I think I've
> found an area I can get those last 16 grams.......Thanks to all that
> convinced me the AAA NimH pack is not the way to go.
> Ed M.
> ----- Original Message ----- 
> From: <jivey61 at bellsouth.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Saturday, January 28, 2006 8:49 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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