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A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

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"water"

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"water"

Postby bugwubber » Sat Feb 08, 2014 12:17 pm

So I have to ask. From the rules...

Rocket must use water as its primary reaction mass.

Does this rule allow room to use the natural crystalline form of water?

:-D

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Re: "water"

Postby WRA2 » Sat Feb 08, 2014 4:43 pm

bugwubber wrote:So I have to ask. From the rules...

Rocket must use water as its primary reaction mass.

Does this rule allow room to use the natural crystalline form of water?

:-D

Bugwubber


I do not see why you couldn't use snow as a reaction mass. Maybe you should do a comparison between liquid water and snow for use as a reaction mass and post the results to the forum. Might be interesting to see the difference in performance.
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Re: "water"

Postby U.S. Water Rockets1 » Sat Feb 08, 2014 10:56 pm

WRA2 wrote:
bugwubber wrote:So I have to ask. From the rules...

Rocket must use water as its primary reaction mass.

Does this rule allow room to use the natural crystalline form of water?

:-D

Bugwubber


I do not see why you couldn't use snow as a reaction mass. Maybe you should do a comparison between liquid water and snow for use as a reaction mass and post the results to the forum. Might be interesting to see the difference in performance.


What happens to the snow crystals when you put them under pressure? Will the snow crystals compress and fuse together and form a solid block? It might depend on the ambient air temperature what happens. If it is near freezing, and the snow is the "packing" type, it would probably fuse, but if it was very cold and the snow was powdery, it would probably not fuse together.
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Re: "water"

Postby bugwubber » Sun Feb 09, 2014 2:24 am

U.S. Water Rockets1 wrote:
WRA2 wrote:
bugwubber wrote:So I have to ask. From the rules...

Rocket must use water as its primary reaction mass.

Does this rule allow room to use the natural crystalline form of water?

:-D

Bugwubber


I do not see why you couldn't use snow as a reaction mass. Maybe you should do a comparison between liquid water and snow for use as a reaction mass and post the results to the forum. Might be interesting to see the difference in performance.


What happens to the snow crystals when you put them under pressure? Will the snow crystals compress and fuse together and form a solid block? It might depend on the ambient air temperature what happens. If it is near freezing, and the snow is the "packing" type, it would probably fuse, but if it was very cold and the snow was powdery, it would probably not fuse together.


I'll have to watch for that. We definitely did not see any change at
-6F/60psi.

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Re: "water"

Postby Water Rocket Expert » Mon Feb 10, 2014 10:41 pm

I thought I once heard that salt water is less dense or something like that. Less density means more water same weight less thrust longer expulsion.

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