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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.

Final launcer design - I LOVE it!

Discussion about Compressors, hose, pipes, fittings, launchers, release mechanisms, and launch tubes.
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Frank
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Final launcer design - I LOVE it!

Post by Frank » Sat Aug 28, 2010 3:15 pm

Here are two pictures of the final version of my launcher. Its been tested a dozen times or so with a plain bottle to 100 psi, and it does a great job. The pull to launch is negligible. The rubber band returns the hinge-style trigger back to the start position and locks the Gardena fitting in the launch position automatically when the bottle is loaded. Works like a charm! Enjoy!

Best to all,
Frank
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Andrew Leigh
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Re: Final launcer design - I LOVE it!

Post by Andrew Leigh » Sat Aug 28, 2010 5:15 pm

Nice,

I had also considered having the Gardena fitting downward loaded as you have but decided against it as generally it is prudent to design devices such that in the event of failure that the device remains secure / safe / unreleased / off etc.

My design was to remove the spring in the Gardena fitting and to have a heavy ring assist in allowing gravity to do its work. My release would have operated as yours does.

Enjoy



Frank
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Re: Final launcer design - I LOVE it!

Post by Frank » Sat Aug 28, 2010 7:26 pm

Well, as far as the launcher goes, it is either released or not, so I'm not sure what kind of launcher-specific failure you are concerned about. I can easily depressurize the setup from the SCUBA tank end of the apparatus. I understand the concept you are promulgating, and generally agree that for more complex systems, its a good rule.

Best regards,
Frank



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U.S. Water Rockets1
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Re: Final launcer design - I LOVE it!

Post by U.S. Water Rockets1 » Sat Aug 28, 2010 9:54 pm

Does this design operate by using the springs under tension to pull down the gardena release and you use the trigger to prop up the release until you are ready to launch when you would pull out the trigger?


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Frank
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Re: Final launcer design - I LOVE it!

Post by Frank » Sun Aug 29, 2010 10:13 am

If I understand your question, then yes, the rubber bands hold the hinge-style trigger mechanism in the "up" position, opposing the downward force of the springs. A pull sufficient to overcome the default, rubber band mediated locked position is required for release. Although not shown there is a string which I've attached about 2" below the acorn nut. This string needs to be pulled with sufficient force (maybe a pound?) to overcome the resistance of the rubber bands and the side springs pull down the Gardena housing with authority.

Discerning eyes will note that there is a section of rubber hose beneath the hose clamp that secures the lower ends of the springs. By loosening the hose clamp, and sliding the hose section up or down slightly, the tension on the springs can be increased or decreased. Also, the vertical 1/4-20 rod with acorn nut has ample extra length inside the wood dowel which can be adjusted upwards or downwards effectively lengthening or shortening its overall length to increase or decrease the force bearing upwards on the Gardena housing.

I'll try to make a short, closeup video if the mechanism is unclear. DISCLAIMER: I don't have the software capacity nor do I know how to edit a video, so it'll probably stink :lol: ...but it might make things clearer.

Best regards,
Frank



Frank
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Re: Final launcer design - I LOVE it!

Post by Frank » Sun Aug 29, 2010 8:52 pm

OK...here's my YouTube launcher video. My first in so many ways, so don't be critical! Since I was doing this single-handed, it took more than 10 seconds for me to walk (outside of the camera view) to the launch string. Boring!!!!

Notice how the 1/4-20 rod returns to the start position. It is then a simple matter to lift the Gardena fitting when mounting a new rocket, and it automatically locks into place. Thereafter, you just pressurize and go again!

[youtube][/youtube]

Best,
Frank



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