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PVC Rocketry???

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
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Unread postAuthor: ammosmoke » Tue Feb 26, 2008 3:08 am

HehEEEEEEEEEEEEEEEEE YEEHAW!!! I mean..... I'm not a redneck... :lol: But yeah, it really does. People who live in Seattle aren't rednecks right?
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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 7:39 am

Funny enough I've all the radio control equipment I need... but it would be pretty costly per launch. Adding a switch to the rocket is a good idea too

Here was my idea... I was going to attach two copper strips right to the end of my barrel hook up two nine volt batteries to it. The rocket would have two separate strips on the out side of the fins. I figure the rocket would be traveling close too 600 fps by the time it hit the ignition strips completing the circuit and hopefully igniting the engine.

My only problem was I wasn't sure if the ignition would be instantaneous. Or if there would be a delay. The circuit would only be complete for less the a millisecond. Would that be enough time?

My goal would be to extend the range of the projectile...not blow anything up... the military has been using a similar system to launch ballistic missiles from their submarines for years
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Unread postAuthor: jackssmirkingrevenge » Tue Feb 26, 2008 7:44 am

The circuit would only be complete for less the a millisecond. Would that be enough time?


I really doubt that, I think a small on-board battery would be your best bet.
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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 7:49 am

I thought so too... I work the battery design on paper see if I can't figure out any thing.

Thanks for the input
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Unread postAuthor: benstern » Tue Feb 26, 2008 9:59 am

Wow..no one even looked at what I said. Shame...
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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 10:12 am

Nope, I did read it and you had a good point... however as long as the thrust from the model rocket was able to over come drag. They must put at least that much thrust in a D size engine.

The initial lift off takes a great deal of energy once that is over come you need only a small amount of energy in comparison to keep up the objects velocity. Just enough to over come drag.

That would be the idea of a pneumatic assist... to over come that initial acceleration.
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Unread postAuthor: dewey-1 » Tue Feb 26, 2008 10:31 am

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Unread postAuthor: jackssmirkingrevenge » Tue Feb 26, 2008 10:48 am

benstern wrote:Wow..no one even looked at what I said. Shame...


Considering this is a rocket assisted projectile, not a rocket propelled one, the thrust doesn't have to be massive. Another thing worth considering is that even a weak rocket would greatly reduce aerodynamic drag in the same way that base bleed ammunition does.
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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 11:57 am

I shoot for distance. So the rockets would be fire at a near 45 degree angle probably 35 degrees. I figure if the extra boost from the rocket gets me and extra 250 - 300 yards it would be worth it.

It would be interesting to see what kind damage it might do at a target if shot horizontally.
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Unread postAuthor: jackssmirkingrevenge » Tue Feb 26, 2008 12:17 pm

Jared Haehnel wrote:It would be interesting to see what kind damage it might do at a target if shot horizontally.


The problem would actually be hitting the target - since the projectile will still be accelerating after it leaves the muzzle, then its maximum velocity (and therefore kinetic energy) will be some distance away from the launcher, meaning your target will be difficult to strike accurately. It's also woth pointing out that if at the moment of firing the rocket is pointing slightly downards, that's the direction the rocket's thrust will be pointing - so your launcher and projectiles are going to have to be pretty well made.
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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 12:56 pm

Your absolutely right...

Which is why I don't plan on shooting at horizontal targets. Too many variables. You'd have to determine burn times/distance, then shoot it at a trajectory to make up for gravity...not to mention wind age which is always a pain with out a rifling or finned rocket. Then of course proper alignment of fins and.... it makes my head hurt just trying to contemplate it all.

No, I just go for distance, if I want accuracy I use my rifle.
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Unread postAuthor: dewey-1 » Tue Feb 26, 2008 12:57 pm

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Unread postAuthor: jackssmirkingrevenge » Tue Feb 26, 2008 1:04 pm

dewey-1 wrote:Hey JSR, you have the link for the drawing I sent you on the RPG?


here you go:

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Unread postAuthor: dewey-1 » Tue Feb 26, 2008 1:11 pm

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Unread postAuthor: Jared Haehnel » Tue Feb 26, 2008 2:09 pm

Snow, snow, snow, Its snowing right now...sigh...

I like your RPG design however it I think it would be time consuming to build. The simpler the better.

I haven't decided yet on a design yet I think I will model it after a single use Estes rocket but beef up the design so its a bit stronger so I can reuse it. Probably use a thin gage aluminum pipe thats 3/4 in diameter. Perhaps copper. It would stand no more then 3 to 6 inches high. I'll probably have some kind of balsa or pine nose cone with tiny fins on the back. I may construct a sabot to launch it from a 1.5 or 2 inch barrel.

Now that I think about it 1" would be the best for the dimensions of the barrel that way the rocket could be centered in the pipe.

It would be cool to fit some kind of glow stick or light or something that would aid in recovery of the rocket. It would look like a tracer. But that all comes later. First we have to get the conceptual design down.

A parachute wouldn't be necessary as When the rocket hits the ground as long as the weight is low the velocity will be pretty slow as well. A rocket with sturdy but light construction will withstand the impact.
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