Hybrid Table

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Doc - 06 Mar 2004 13:09 GMT

We are now offering hybrid launch support at all NEPRA launches. Everyone
is welcome to use the equipment, but we can't give away free nitrous for too
long before we would go broke. We need to come up with a cost accounting
table for filling tanks. I've scoured the net looking for tables or
spreadsheets with manufacturers, tank sizes, and/or fill weights. There is
nothing I've seen yet.

I don't want to overcharge, but we can't waste money either. What we charge
for a regular launch fee wont cover nitrous.

What do you guys charge?
By the lb or cc?
How do you determine what to charge for the fill?
If they have to dump, do you charge for a second fill?
What if it never leaves the pad?
Anyone have a table of fees?

--
Drake "Doc" Damerau
www.rocketmaterials.org
NEPRA President
NAR Section 614
NAR 79986 L3
www.nepra.com
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Alex Mericas - 06 Mar 2004 14:59 GMT

My plan is simple. I offer N2O at cost. I've found information
from various sites (mainly the motor mfgs) on tank volume. I round
UP to the nearest pound. A quickie table:

HT 300 & 440 tanks: 1 lb
HT 835 tanks: 2 lbs
RATT, WCH, PP H,I,J: 1 lb (the PP-J140 is right at 1lb)
RATT K240: 3 lbs

A dump counts as a fill and would result in being charged again for
a second fill.

> We are now offering hybrid launch support at all NEPRA launches. Everyone
> is welcome to use the equipment, but we can't give away free nitrous for too
[quoted text clipped - 21 lines]
> www.nepra.com
> Remove "My Shorts" to reply

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Les Kramer - 06 Mar 2004 15:51 GMT

Here is what we use:

HyperTEK RATT Works

300cc - 3/4# H70 - 1/4#

440cc - 1# I80 - 1/2#

835cc - 2# I90 - 3/4#

1685cc - 4# K240 - 2#

2800cc - 6# L600 - 3#

Les Kramer #70965 L-2 / Club President
Northern Ohio's TRI-CITY SKY BUSTERS ROCKETRY CLUB, NAR #535
Club website: www.SkyBusters.org
Club e-mail: SkyBusters@SkyBusters.org
Club e-mail site: http://groups.yahoo.com/group/SkyBusters

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Andrew MacMillen - 06 Mar 2004 19:14 GMT

Not a fee table, but all the motors and their fill weights.

http://hybrids.macrockets.com/forum/viewtopic.php?t=50

I'd consider charging 1.25 X the weight X your cost/lb for each fill
fair, with each fill counted; fly, no-fly, or dump. This would cover
boil-off, venting, leaks, etc.

Signature

Andrew MacMillen
NAR/TRA L2
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Doc - 07 Mar 2004 10:33 GMT

That's perfect. Thanks Andrew, and everyone that responded.

--
Drake "Doc" Damerau
www.rocketmaterials.org
NEPRA President
NAR Section 614
NAR 79986 L3
www.nepra.com
Remove "My Shorts" to reply

> Not a fee table, but all the motors and their fill weights.
>
[quoted text clipped - 35 lines]
> - - - - - - - - - - - - - - - -
> Remove "-REMOVE-THIS-" to reply

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Kevin Trojanowski - 07 Mar 2004 16:38 GMT

> Not a fee table, but all the motors and their fill weights.
>
> http://hybrids.macrockets.com/forum/viewtopic.php?t=50

Thanks, Andrew -- you just saved me some time! Only two of us in our
club have nitrous bottles, and while I'd love to just give it away, I
cannot afford to (unless I don't want to fly any rockets).

I was going to produce a table exactly like the spreadsheet, so that
folks can pay actual nitrous cost.

-Kevin

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Deaver - 07 Mar 2004 14:05 GMT

I would use a scale and charge actual weight used. A large Rattworks will
use alot more in actual weight with
prechilling and venting in the summer. Get a refrigerant
scale and measure before and after weights.
Gary Deaver

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Joel Corwith - 07 Mar 2004 18:44 GMT

GREAT thread! Don't forget that last little bit in the tank is worthless so
even if the bottle costs x to fill, y is still an expense when you're only
getting z from the tank.

Joel. phx

> I would use a scale and charge actual weight used. A large Rattworks will
> use alot more in actual weight with
> prechilling and venting in the summer. Get a refrigerant
> scale and measure before and after weights.
> Gary Deaver

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Kevin Trojanowski - 07 Mar 2004 19:03 GMT

> GREAT thread! Don't forget that last little bit in the tank is worthless so
> even if the bottle costs x to fill, y is still an expense when you're only
> getting z from the tank.

Not entirely true. Although those last few pounds are all but
worthless, if you're keeping tabs on your gas, you don't ever really use
them, so you pay for it once, and that's it. Much like the cost of the
tank itself.

-Kevin

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Model Forum / General / Rockets / March 2004

Hybrid Table