Full bore rocket questions

Discussions about rockets, construction materials, adhesives, nozzles, nosecones and fin design.
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Flash
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Full bore rocket questions

Post by Flash »

Operating in the 100 psi range on a full bore 22mm launcher with long tube inside bottle, what kind of performance should I get from just single 2Lt bottles? Rocket design is Quest fins and nose protector on 2Lt bottle but not with quest 9mm nozzle and not on quest launcher which is rated at 80 psi.

With the fins about as far aft as they can get without adding a fin mount tube at the bottom of the bottle, do I still need some nose weight in the form of a large washer maybe?

What is a good next step rocket design in performance for this type of launcher setup(full bore)?

Thank you!!!
Flash
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bugwubber
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Re: Full bore rocket questions

Post by bugwubber »

Yes, I have found weight helps the rocket keep up its momentum. I just hit 232ft with a 2liter and the simulator shows over 300ft is possible. Speeds could qpproach 140mph briefly.

But, just say no to metal!

Seriously though if you think of each bottle as an explosive grenade, every bit you attach to the rocket think- I won't mind that flying back at me...

Speaking of, you should download one of the simulators- they are very informative.
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Flash
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Re: Full bore rocket questions

Post by Flash »

Thanks, and thanks on mentioning the simulators, I need to do that for sure. I use them on my solids, guess I should do the same on water.
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Re: Full bore rocket questions

Post by bugwubber »

As far as rocket design, I tend to lean towards unconventional but simple. I find the parachute-less designs make for faster turnaround and more reliable operation.

Foam rubber and duct tape nose ones can help you quickly gain launch experience and let you test fin designs. Just start at lower psi first.

The Laissez rocket I just posted in photos was incredibly easy to make- it's just 3 bottles glued end to end, with fairings cut from a forth. Hope that helps

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Flash
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Re: Full bore rocket questions

Post by Flash »

I took a look at the Laissez rocket, very cool design and nice performance.
Thanks!
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Nick B
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Re: Full bore rocket questions

Post by Nick B »

Flash wrote:Operating in the 100 psi range on a full bore 22mm launcher with long tube inside bottle, what kind of performance should I get from just single 2Lt bottles? Rocket design is Quest fins and nose protector on 2Lt bottle but not with quest 9mm nozzle and not on quest launcher which is rated at 80 psi.

With the fins about as far aft as they can get without adding a fin mount tube at the bottom of the bottle, do I still need some nose weight in the form of a large washer maybe?

What is a good next step rocket design in performance for this type of launcher setup(full bore)?

Thank you!!!
Flash

The best thing you can do with 2 liters is add nose cone weight like (a washer) if you are tumbling, or move up to a 4 liter or more assy. Longer rockets increase stability and thrust duration. You could shave down the fin size a tad, but you will risk de-stabilizing the rocket at a tipping point. The Quest fin design is solid for stable flight for 2 liters.

250/300 feet is the average for 2 liters.
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U.S. Water Rockets1
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Re: Full bore rocket questions

Post by U.S. Water Rockets1 »

Flash wrote:Thanks, and thanks on mentioning the simulators, I need to do that for sure. I use them on my solids, guess I should do the same on water.
With a short rocket like that you have to add nose weight to offset the fin weight. The fins can actually make the rocket stable in a fins-forward orientation... the rocket can actual flip over after burnout and fly with the fins leading!
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Prodigy Rocketry
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Re: Full bore rocket questions

Post by Prodigy Rocketry »

On our first batch ever 2 liter designs we just used some sand as nose weight. We found the more sand (within reason now) the higher the flight. Also, 140psi launches were the norm; only lost one bottle trying to creep past that known. I also cut a foam football in half to make two bounce bumper cone for the landing. They duct tape on very easily. These rockets take laess than 30 minutes to build to. Good luck with your ideas.
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