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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.

Pressurization Distance?

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Alien Space Agency
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Pressurization Distance?

Post by Alien Space Agency » Sun Jun 12, 2016 11:34 am


Can we change the distance where we can safely stand and pressurize our rocket depending on the maximum pressure of our rocket?

For example, I tried to break the Class A record @150 psi, and I am standing ~10m away from the pad. Could it still be acceptable?

As you can see, you First World countries have a greater advantage from Third World ones. Pricing of the materials plays a big part in this.

I mean, I'm just a middle school kid tinkering around water rocket staging and is aiming high.

So to reduce costs I shall propose pressure-dependent safe distances.

Below 100psi: 5m
100-150: 10m
150-300: 20m
300-max: 40m

I guess that would be enough to avoid shrapnel.
By the way, I only aim to launch at 125psi. TH: TH:

Nothing can stop a curious mind from inventing- Anonymous

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Re: Pressurization Distance?

Post by anachronist » Wed May 24, 2017 7:13 pm

The cost of 50 feet of pressure hose is the least of your worries if you aim to enter a competition. 50 feet of 200psi hose costs US$15 or more, which isn't much compared to the much more significant cost of an altimeter, followed by the required onboard camera.

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