Mythbusters Hybrid Rocket -Ping Erik Gates

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J.A. Michel - 18 Feb 2007 03:08 GMT

I didn't want to say 'meat' or 'salami' rocket ;-) Erik, you were there,
did the salami grains actually burn? The way it looked to me, the thing
could have been off the pad on just tank pressure alone.

Joe Michel
NAR 82797 L2

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Erik Gates - 18 Feb 2007 04:24 GMT

The nozzle design was such that only a ½" of graphite was holding the nozzle
in. Unlike a AMW that the whole nozzle is held in. Each time it came up to
pressure it blew the nozzle! I believe the fuel lit, but the nozzle design
had them doomed from the start

Erik Gates

>I didn't want to say 'meat' or 'salami' rocket ;-) Erik, you were there,
>did the salami grains actually burn? The way it looked to me, the thing
>could have been off the pad on just tank pressure alone.
>
> Joe Michel
> NAR 82797 L2

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Len Lekx - 18 Feb 2007 13:18 GMT

>The nozzle design was such that only a ½" of graphite was holding the nozzle
>in. Unlike a AMW that the whole nozzle is held in. Each time it came up to
>pressure it blew the nozzle! I believe the fuel lit, but the nozzle design
>had them doomed from the start

I would think that their idea of coating the inside of the core
with BP had something to contribute to its' demise as well. Ordinary
BP burns too quickly to make a good pyrogen. Maybe they should try
using smokeless next time... :-)

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J.A. Michel - 18 Feb 2007 15:24 GMT

>>The nozzle design was such that only a ½" of graphite was holding the
>>nozzle
[quoted text clipped - 8 lines]
> BP burns too quickly to make a good pyrogen. Maybe they should try
> using smokeless next time... :-)

I agree. Adding the doughnut of AP for a preheater grain was a much better
idea.

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tai fu - 20 Feb 2007 04:38 GMT

also complicating the fact is that blackpowder does not burn hot enough. The
pyrogen mix should be metal-perchlorate reaction that burns much hotter
compared to blackpowder. APCP is good for that.

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TAI FU

>
>>The nozzle design was such that only a ½" of graphite was holding the
[quoted text clipped - 9 lines]
> BP burns too quickly to make a good pyrogen. Maybe they should try
> using smokeless next time... :-)

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Alex Mericas - 20 Feb 2007 14:42 GMT

> also complicating the fact is that blackpowder does not burn hot enough. The
> pyrogen mix should be metal-perchlorate reaction that burns much hotter
> compared to blackpowder. APCP is good for that.

West Coast hybrids uses a BP based pre-heater. You mix BP with an
inhbitor fluid that slows down the burn. No disclosure on what the
fluid actually is. I know it evaporates pretty easily and smells
somewhat like kerosene or diesel.

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Glen Overby - 20 Feb 2007 17:37 GMT

>inhbitor fluid that slows down the burn. No disclosure on what the
>fluid actually is. I know it evaporates pretty easily and smells
>somewhat like kerosene or diesel.

You could ask them for the MSDS on it.

Glen Overby

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Model Forum / General / Rockets / February 2007

Mythbusters Hybrid Rocket -Ping Erik Gates