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General Forums => The O' Club => Topic started by: Penguin on October 11, 2011, 09:59:01 PM

Title: Backyard Rocket
Post by: Penguin on October 11, 2011, 09:59:01 PM
Hello,

I've been messing around with vinegar and baking soda rockets lately, and I've noticed that a cork is a very efficient way to let pressure build up in a controlled way.  However, once I start the reaction I cannot choose when the rocket should launch.  Though I've achieved an apogee of around 4-5 stories I know that I could get more bang for my buck.  Is there any way that I can keep the rocket from flying away until I'd like it to so as to let the pressure build up further?

-Penguin
Title: Re: Backyard Rocket
Post by: FiLtH on October 11, 2011, 10:07:47 PM
Devise a piston base that the cork rests against. Have a small valve release a tiny bit of the fluid at the base below the piston slowly till it goes far enough to allow the cork to pop out.

Probably would just force the rocket off the cork. I dont know. Dammit Jim Im a Doctor not a rocket scientist!
Title: Re: Backyard Rocket
Post by: PFactorDave on October 11, 2011, 10:16:49 PM
You need to look at the clamps that hold real rockets on the launch pad until they motors are burning evenly.  The space shuttle uses (used a similar system) them too.

You could design a system that holds the rocket against the base and also holds the cork in until the clamps are released.  Of course, be aware that you are creating a pipe bomb and it will be somewhat dangerous.
Title: Re: Backyard Rocket
Post by: AAJagerX on October 11, 2011, 11:21:19 PM
Stop goofing off with silly stuff and use real rocket motors.  They're more fun anyway.  

If you HAVE to play with the baking soda and vinegar, build a platform with the corks attached.  Lower your "rocket" onto the platform until you get a solid seal.  Then use a spring tensioned arm mounted on a bracket with a fulcrum to hold the "rocket" in place until your desired pressure is attained.  Adjust the spring tension as needed to break the fulcrum tension at your optimal pressure.  

Title: Re: Backyard Rocket
Post by: morfiend on October 12, 2011, 12:25:46 PM
A plastic spring clamp could be used to hold the "rocket" in place.

 I've used a similar device to hold 2liter soda bottle rockets,I like to use water and compressed air instead of baking soda and vinegar but it's the same principle.

  I mounted a clamp on a suitable peice of wood,glued the cork inplace and drilled a hole through the cork and board.I use a ball inflator attached to a hose from my compressor,pump about 45 psi and the bottle will go seveat hundred feet up.  My grandson gets a kick outta getting wet from the rocket!!!


   YMMV





   :salute
Title: Re: Backyard Rocket
Post by: uptown on October 12, 2011, 12:43:41 PM
you do know your yard will smell like a ...well nevermind.
Title: Re: Backyard Rocket
Post by: Babalonian on October 12, 2011, 01:07:47 PM
You need to look at the clamps that hold real rockets on the launch pad until they motors are burning evenly.  The space shuttle uses (used a similar system) them too.

You could design a system that holds the rocket against the base and also holds the cork in until the clamps are released.  Of course, be aware that you are creating a pipe bomb and it will be somewhat dangerous.

And this is why, today, NASA is going broke so fast!  :devil

Ladies and gentlemen, let me introduce to you the latest and greatest development to come at us from the great minds at NASA:
(http://www.apexfasteners.com/fasteners/images/Quick_Release_Dentent_Ring_Pin.jpg)
Those smartie pants also tried to pass us a small cylindrical piece of wood with a small hole drilled through the sides of it as a form of cork-stopper, but we're too smart for them and sent it back because we caught it in time! 

Long gone are the days where kids earned their model rocketry chops with the kerosene can in the shed and uncle Fred's old box of grenades.
Title: Re: Backyard Rocket
Post by: Shuffler on October 12, 2011, 01:57:00 PM
When you designed the engine... what pressures did you design for. Did you run finite on it to confirm. What safety did you design in.... 2-1, 3-1?

Once you know then you can develope a method of pressure buiding to maximize your launch capabilities.




..... or you can just hit and miss till you perfect the launch. :)
Title: Re: Backyard Rocket
Post by: Penguin on October 12, 2011, 06:17:24 PM
When you designed the engine... what pressures did you design for. Did you run finite on it to confirm. What safety did you design in.... 2-1, 3-1?

Once you know then you can develope a method of pressure buiding to maximize your launch capabilities.




..... or you can just hit and miss till you perfect the launch. :)

I have no clue about safety.  I wear lab goggles and stand far away once the reaction starts.

A plastic spring clamp could be used to hold the "rocket" in place.

 I've used a similar device to hold 2liter soda bottle rockets,I like to use water and compressed air instead of baking soda and vinegar but it's the same principle.

  I mounted a clamp on a suitable peice of wood,glued the cork inplace and drilled a hole through the cork and board.I use a ball inflator attached to a hose from my compressor,pump about 45 psi and the bottle will go seveat hundred feet up.  My grandson gets a kick outta getting wet from the rocket!!!


   YMMV





   :salute

I'm just a layman on this, would you mind explaining it more simply?

-Penguin
Title: Re: Backyard Rocket
Post by: morfiend on October 12, 2011, 06:25:14 PM
 Take a small piece of plywood and mount the clamp to it,a screw long enough for the job.   Then glue a cork or suitable stopper to the board and thats it!

   couldnt be simpler,the clamp holds the 2 liter bottle on to the cork and I simply squeeze the clamp to release and launch the rocket. you could extend the clamp arms with some dowel and tape so you dont get too wet,thats what the grandson like,squeezing the clamp open and getting wet!





   :salute
Title: Re: Backyard Rocket
Post by: Penguin on October 12, 2011, 06:57:48 PM
Ok, so what kind of a clamp would I need?  I know, I know, I'm a suburban nerd with no clue how to make anything.

-Penguin
Title: Re: Backyard Rocket
Post by: Shuffler on October 13, 2011, 01:38:08 PM
Ok, so what kind of a clamp would I need?  I know, I know, I'm a suburban nerd with no clue how to make anything.

-Penguin

Don't forget the FAA clearance process................... :)

lol seriously though... You should read up on rocketeering. It is a lot of fun. I was into rockets when I was young..... a long long time back.
Title: Re: Backyard Rocket
Post by: Dichotomy on October 13, 2011, 02:01:07 PM
What did you do?  Throw a rock as high as you could and call it 'rocketing'?  Did you ever hit a dinosaur?
Title: Re: Backyard Rocket
Post by: Shuffler on October 13, 2011, 02:12:06 PM
What did you do?  Throw a rock as high as you could and call it 'rocketing'?  Did you ever hit a dinosaur?

Yes and yes..... before I hit one they were just known as Dinos.
Title: Re: Backyard Rocket
Post by: Maverick on October 13, 2011, 02:16:58 PM
Take a look at the old water rocket systems and see if any of their ideas can be modified to fit a baking soda rocket.
Title: Re: Backyard Rocket
Post by: Barrett on October 13, 2011, 02:18:47 PM
you do know your yard will smell like a ...well nevermind.

LOL good one  :aok