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We wanted to keep the rocket simple, light and strong.
Thats why we took a hard PET bottle of 1.5 liter instead of a 2 liter. We could not find any 2 liter hard bottles any more..
Neverless this rocket is capable of holding high pressures! Without any reïnforcements!
We only have to wait for a good windless/ sunny day and then we will launch this.
First launch will be at a pressure around 12 bar. Afther that launch we build up pressure. And pushing this rocket up in the air as high as possible
when you say a hard pet bottle what do you mean?..........i manage to get my standard 2litre coke bottles up to 12 bar and havent exploded any yet.....
with the nose cone and recovery system (if this is not a trade secret) what does your wrocket weigh?
A few years ago we had hard pet bottles. Nowadays there are only weak bottles. Easy to squeeze and are not capable of holding the same pressure.
The standart (new) coca cola bottle burst at around 10 bar ( we heared..) we have not tested it ourselfs but ik read it somewhere on the internet..
The bottle we used for this rocket is capable of holding 13 / 14 bar so that is quite a lot for an unmodified bottle.
And about the weight of the rocket:
How do i say this.. (my englisch is not so good ) we did not put the rocket on a weightscale yet. I will do that in a few days. We will weight this rocket with onboard camera and altimeter. I guess it wil be around 300 gram. But i can be wrong!
A good bottle here will hold 10 bar, but the feet on the bottom are gone. Most let go around 9 bar. I use 8 max on my stock 2 liter bottle rocket with good results (361 feet or 110 meters)! It's really fun to make some noise with the bottles you don't like! BOOOOOOOOOOOOOMMMMMMMMMM!!!!!!!!!!!!!!!!!!!!..................................lets do that again. 14 bar......hum..... man that would be cool to hear blow up! At a safe distance of course. SAFETY FIRST!
mmmmm looks like i need to get a better pressure tester because the 2 i have both say that im putting 12 bar into my 2 litres coke bottles and there not exploding i guess ill head to the hardware store and buy another one
this is with 3 different makes of pump and all read he same .........
andicirk wrote:mmmmm looks like i need to get a better pressure tester because the 2 i have both say that im putting 12 bar into my 2 litres coke bottles and there not exploding i guess ill head to the hardware store and buy another one
this is with 3 different makes of pump and all read he same .........
How much does your 2 liter bottle weigh? I weighed some of mine and they weigh 46 to 48 grams. This might help with why our bottles hold different pressures. If others would do the same it would be interesting to see the results.
reno1 wrote:A good bottle here will hold 10 bar, but the feet on the bottom are gone. Most let go around 9 bar. I use 8 max on my stock 2 liter bottle rocket with good results (361 feet or 110 meters)! It's really fun to make some noise with the bottles you don't like! BOOOOOOOOOOOOOMMMMMMMMMM!!!!!!!!!!!!!!!!!!!!..................................lets do that again. 14 bar......hum..... man that would be cool to hear blow up! At a safe distance of course. SAFETY FIRST!
I think we should use PSI instead of Bar, because Bar is too low resolution. You measure your pants in centimeters, not meters.... so either you use PSI or millibars or something to come up with a more precise measure. Bars are too coarse.
id like to post in something else but i only have one pressure tester that works in psi( ive had this one for about 15 years i ot it i the uk) i checked the pump pressure tonight and ot 170 psi and 12bar which is fairly correct ..... 12bar = 174.04....psi
Can anyone comment regarding the purpose of the "hard" bottles? Were they the type that you return and they wash out and refill? Were they meant to be returned like this and re-used, or were they just meant to be discarded? Why would they be so much stronger if they were not designed to be re-used.
U.S. Water Rockets1 wrote:Can anyone comment regarding the purpose of the "hard" bottles? Were they the type that you return and they wash out and refill? Were they meant to be returned like this and re-used, or were they just meant to be discarded? Why would they be so much stronger if they were not designed to be re-used.
In the UK some carbonated drinks are marketed as 'premium' products, and the extra bulk of thick bottle walls gives them a luxury image.
) we did not put the rocket on a weightscale yet. I will do that in a few days. We will weight this rocket with onboard camera and altimeter. I guess it wil be around 300 gram. But i can be wrong!
14 bar......hum..... man that would be cool to hear blow up! At a safe distance of course. 
