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Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 12:10 pm
by Avnish
Question!

Suppose I make two rockets.

One with a 1.5l bottle with a nose cone on top
Second with a 1.5l bottle having another same 1.5l bottle on top and then the same nosecone as the previous case

Keeping the dry mass of both the Rockets same and then using the same parameters in both the cases, which of these would travel farthest.
P. S - The pressure chamber is equal in both the Rockets.

Thanks in advance!

Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 12:25 pm
by bugwubber
Avnish wrote:It's hell busy here. And unfortunately, I won't get much time for testing. 1.5 hours at max. Way too congested here :sigh:
Know what you mean. My weekend was spent replacing the kitchen sink with a much larger one that required extensive modifications to the cabinet. No time for anything else until that was done!

Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 1:14 pm
by Avnish
No cabinets here but I had loads of assignments and reports. That too for every subject. Still a few left :(

What about the question btw :p

Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 2:53 pm
by Water Rocket Expert
In my opinion, the one that is more stable is going further. Probably the one with the two bottles, but then if the other one is very stable (not over stable, yes that does exist!) it may go further. :D

Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 5:03 pm
by bugwubber
Avnish wrote:No cabinets here but I had loads of assignments and reports. That too for every subject. Still a few left :(

What about the question btw :p
Sorry missed your question.

The longer rocket would be better, and you would be able to reduce the ballast in the nosecone required to keep it stable.

Re: Maximum horizontal distance competition

Posted: Thu Mar 20, 2014 8:37 pm
by Water Rocket Expert
Bugwubber is correct as he restated what I said.

Re: Maximum horizontal distance competition

Posted: Sat Mar 22, 2014 10:20 pm
by U.S. Water Rockets1
The dry mass is not given, so in theory there could be no winner. If you put 150 pounds of ballast in each rocket, then neither one would move at all, so it would be a tie.

This is just a thought experiment to get you to think about all of the variables involved. Making the rocket longer is going to make it more stable and it will fly farther, BUT there may be some situations where the weight makes a difference. Tweaking each size rocket for optimum performance means that each one has a "best" weight that makes that size rocket work to the maximum of the design. For example, the long right with no ballast may not go as far as the short one with 100g in the nose because the long one may be too light.

The lesson here is that you should tune the rocket in all ways to make it perform best, there is no one parameter that will make a rocket the best.

Re: Maximum horizontal distance competition

Posted: Sun Mar 23, 2014 12:26 am
by Water Rocket Expert
He is asking which one is easiest to make go the furthest. Of course you could try to life a horse but he needs to be practical and know which usually works better.

Re: Maximum horizontal distance competition

Posted: Mon Mar 24, 2014 1:49 am
by Avnish
Guys :D

Secured the first position!!
Yayyyyyy!!

Got 127.5 meters at 90psi

Thanks everyone :)

Re: Maximum horizontal distance competition

Posted: Mon Mar 24, 2014 7:00 am
by Water Rocket Expert
Whoa, are you serious??? I was expecting more like 50 meters at the most with a 1.5 liter but hey whatever you say!

Re: Maximum horizontal distance competition

Posted: Tue Mar 25, 2014 2:55 pm
by bugwubber
Avnish wrote:Guys :D

Secured the first position!!
Yayyyyyy!!

Got 127.5 meters at 90psi

Thanks everyone :)
Awesome! Congratulations! Would love to see a picture of your rocket if you are able to post it.