Thursday, May 03, 2007 at 07:59
Do the bottle rockets at the local school fete every year.
Generally get 20 to 30 metres with a 1 litre soft drink bottle.
The kids use hand pumps though.
The secret is to pump slowly and steadily until it goes.
For the cork, we put an old tyre valve stem through a rubber cork, and push the cork into a 1 litre soft drink bottle.
1 to 2 cups of water gets the best result.
Too much water and the intial acceleration is less.
Harder you push the cork in the further it goes once it lets go.
(Little secret, great fun when the littlest kid there gets an extra push on the cork, and all the bigger kids get beaten :o), tis a pleasure to see the smile of success at beating all the others , the ones who normally beat the little kids at most things.)
1 litre bottles go further than 2 litre bottles, less air resistance, since the bottles fly 2/3rds of the distance empty.
Yes, when we made up the rockets, my mate and I had to, in the name of experimentation, fly rockets all afternoon to find the best combination.
The wives just called us big kids and left us to it.
So the answer is, the size of the pump doesn't make any difference, if anything, the slowest one may produce the best distance.
Watching the pressure guage, it is hard to find a cork in the soft drink bottle that will go much beyond 50 psi before letting go. Found rubber corks worked the best.
Now, of course you will need to build a rig and experiment to prove me wrong!
AnswerID:
237594
Follow Up By: Member No 1- Thursday, May 03, 2007 at 10:49
Thursday, May 03, 2007 at 10:49
I reckon can get the corks to hold at higher pressure ..but at what pressure does the pet bottles hold before rupturing?
FollowupID:
498679
Follow Up By: Member - Oldplodder (QLD) - Thursday, May 03, 2007 at 20:41
Thursday, May 03, 2007 at 20:41
Only one way to find out. Test to destruction as the Myth Busters say.
You done it yet?
FollowupID:
498810
Follow Up By: Member No 1- Friday, May 04, 2007 at 07:28
Friday, May 04, 2007 at 07:28
nope..not yet...but am going to give it a try on sunday
FollowupID:
498912
Follow Up By: Middle Jeff - Friday, May 04, 2007 at 08:10
Friday, May 04, 2007 at 08:10
PET bottles will blow the lid off before they explode, I worked in a warehouse once and a forklift dropped a pallet of no name lemonade the things started to bounce everywhere great fun until the lids started to let go, one got me in the back and put on the floor with five little bruise marks on my back, sore and sticky!
Have fun
Craig
FollowupID:
498918