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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.

EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
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John K
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EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by John K » Sat Feb 21, 2009 12:18 am

Here in Minnesota, rubber band deployments don't work in the winter. Rubber just doesn't have any memory in the cold. And our contest rules don't allow any metal anywhere on the rocket. I finally came up with an idea that works every time.
A small syringe (1ML) used to administer medicine can be used as a spring to push out a parachute. Just melt the tip to seal the syringe into a cylinder. Take a look at this photo. it is pretty self explanatory. I made the syringe a lot more lively by blowing compressed air at the cylinder opening as I inserted the plunger. I also glued a quarter sized balsa wood sheet to the syringe to help push out the parachute.
My kitchen scale says the spring delivers about 3 pounds of force at full compression, and has 3 good inches of travel. If you need more force, use a bigger syringe.
Lubing up the piston with plumbers grease (Pure Silicone) helpes. Don't use oil, it swells up the piston.
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rockets-in-brighton
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by rockets-in-brighton » Sat Feb 21, 2009 5:40 am

John K wrote:Here in Minnesota, rubber band deployments don't work in the winter. Rubber just doesn't have any memory in the cold. And our contest rules don't allow any metal anywhere on the rocket. I finally came up with an idea that works every time.
A small syringe (1ML) used to administer medicine can be used as a spring to push out a parachute. Just melt the tip to seal the syringe into a cylinder. Take a look at this photo. it is pretty self explanatory. I made the syringe a lot more lively by blowing compressed air at the cylinder opening as I inserted the plunger. I also glued a quarter sized balsa wood sheet to the syringe to help push out the parachute.
My kitchen scale says the spring delivers about 3 pounds of force at full compression, and has 3 good inches of travel. If you need more force, use a bigger syringe.
Lubing up the piston with plumbers grease (Pure Silicone) helpes. Don't use oil, it swells up the piston.
Hi John, and welcome to the forum!

Thanks for this interesting idea. How is the syringe triggered - does your mechanism use a mechanical or electronic timer that we can't see oin the picture, and how does the timer release it at the right time?


Cheers
Steve
Rockets-in-Brighton
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John K
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by John K » Sat Feb 21, 2009 11:14 am

Hi Steve, There are no hidden tricks on this release. The green tube is a heat shrunk
20 ounce Mountain Dew bottle.
CIMG1029.JPG

I made a form out of a tree branch on my lathe that is 1.675 (inch) and with a 30
degree angle on it. (Metal would have been better because wood shrinks about .020 over the net week.) Then put some baby powder on it as a release agent and shrink it down.
CIMG1030.JPG
Anyway, this seemes to be the right size to barely fit over the FTC tube.
So get the parachute loaded, slide the green tube over the FTC tube and tape it on.
(other wise the syringe spring will push it off) Once you pressurise the tube to about 40 PSI, the FTC tube will expand and hold the green tube in place. Remove the tape, fill the FTC to 125 PSI, and fire away.
When the pressure is all gone, the syringe will start to push itself off and release the parachute. This take about 4 seconds to do because the green tube needs to get air into it. You can speed this up by drilling a couople of small holes in the green tube, but do it in a place that can be taped over in case it releases too fast. My assembly needed one .062 (inch) hole to get it to release at appogee.
CIMG1022.JPG

Feel free to ask more questions, As far as I can tell, this has not been done yet, and seems like once a few people try it, we can refine the process and really get a nice
easy to make release. No patents or secrets, just pure easy fun.
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by WRA2 » Sat Feb 21, 2009 1:05 pm

John K wrote:Here in Minnesota, rubber band deployments don't work in the winter. Rubber just doesn't have any memory in the cold. And our contest rules don't allow any metal anywhere on the rocket.
Hello John K,

Welcome to the forum :W

Are you referring to the WRA2 policy of no metal on the rocket or a local competition?

You would be welcome to post the results of your local competition to our "personal best" topic in the forum. If there is an interest in this from others we could create a stand alone topic in the forum where competition directors could post their results and if there is a lot of interest we could add a dedicated page to our website with the results of local competitions. This would be a good way to bring national and worldwide attention to the winners of these competitions. 8)


Lisa Walker,
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John K
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by John K » Sat Feb 21, 2009 4:14 pm

Our contest was a very informal event.
Believe it or not, the company I work for sponsers this event every year. This is the sixth anual contest. My company is MTS out of Eden Prairie, MN. We sell products all over the world that shake things to death, and deliberatly wear things out prematurely so they can be made better. This event is held during "Engineering Week" I work there as a prototype Machinist.
Their "no metal" rules are to simplify the rockets so that anybody can build them. And Most are made out of the 2 liter bottles. I entered my FTC rocket in the unlimited catagory.
There were a lot of kids building rockets. It was very important that they win all the prizes. I declined any prize. I just did this to show off what a Machinist can do with a FTC rocket.
I really do think I hit close to 750 feet high. And that was the Maiden flight.
The best 2 liter height might have hit 200 feet.
I will tinker some more.

You should see the idea I have for a 2 stage rocket............ John



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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by WRA2 » Sat Feb 21, 2009 4:31 pm

John K wrote:Our contest was a very informal event.
Believe it or not, the company I work for sponsers this event every year. This is the sixth anual contest. My company is MTS out of Eden Prairie, MN. We sell products all over the world that shake things to death, and deliberatly wear things out prematurely so they can be made better. This event is held during "Engineering Week" I work there as a prototype Machinist.
Their "no metal" rules are to simplify the rockets so that anybody can build them. And Most are made out of the 2 liter bottles. I entered my FTC rocket in the unlimited catagory.
There were a lot of kids building rockets. It was very important that they win all the prizes. I declined any prize. I just did this to show off what a Machinist can do with a FTC rocket.
I really do think I hit close to 750 feet high. And that was the Maiden flight.
The best 2 liter height might have hit 200 feet.
I will tinker some more.

You should see the idea I have for a 2 stage rocket............ John
Feel free to post the results (or have your competition director) post the results in our "Personal or Team Best" forum:

http://www.wra2.org/forum/viewforum.php?f=36

Just start a new topic with the name of your competition and post the results. You could also post past results as well since you competition has been going for many years. Fee free to introduce others from your competition to this forum and the WRA2 :WRA2:


Lisa Walker,
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:WRA2:The Water Rocket Achievement World Record Association :WRA2:

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U.S. Water Rockets1
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by U.S. Water Rockets1 » Sat Feb 21, 2009 10:22 pm

John K wrote:Here in Minnesota, rubber band deployments don't work in the winter. Rubber just doesn't have any memory in the cold. And our contest rules don't allow any metal anywhere on the rocket. I finally came up with an idea that works every time.
A small syringe (1ML) used to administer medicine can be used as a spring to push out a parachute. Just melt the tip to seal the syringe into a cylinder. Take a look at this photo. it is pretty self explanatory. I made the syringe a lot more lively by blowing compressed air at the cylinder opening as I inserted the plunger. I also glued a quarter sized balsa wood sheet to the syringe to help push out the parachute.
My kitchen scale says the spring delivers about 3 pounds of force at full compression, and has 3 good inches of travel. If you need more force, use a bigger syringe.
Lubing up the piston with plumbers grease (Pure Silicone) helpes. Don't use oil, it swells up the piston.
Hi John,

It's good to see more people working with FTC rockets! With more people making them then there will be more discoveries made and more people to use them. That can only be a good thing!

You look like you had great success shrinking bottles. We avoid bottles with textures and logos molded into them because they are so hard to get smoothed out. Your technique seems to work very well.

Thanks for the photos, and welcome to the forum!


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Tim Chen
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by Tim Chen » Sat Feb 21, 2009 10:57 pm

:W

Hi John! Welcome!


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John K
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Re: EASY DEPLOYMENT FOR FTC PARACHUTE USING A SMALL SYRINGE

Post by John K » Sun Feb 22, 2009 1:57 pm

Thanks for the warm welcome. This is a pretty cool hobby, And it relates well with my love for Radio Controlled electric airplanes.
I did want to mention which bottles I use for shrinking.
20 oz Coke bottles work best for sealing the ends of the nose cones. But they don't give a very long cylinder. 1 inch at best.
For parachute tubes, Mountain Dew worked best for me followed by the 16 0z 7-UP bottles. And I have to stress using a release agent like baby powder on your form, or you better be one strong boy to get the shrunk bottle off of the form.
John



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