How can i make a "one way air nozzle" (a nozzle where air goes forward but not back)?

I'm making water rockets. pocket sized ones. those fly ~5 meters. i want to improve the results and move forward to bigger rockets, by making a one-way air nozzle. the air will need to go inside the rocket, but not out. i tried it with my simple bicycle pump, but the air leaks. please give me instructions or suggestions, and i cant buy a new pump. my rocket should meet the requirements of a simple, cool, pocket sized, homemade rocket.

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AndyGadget8 years ago
Find an old bicycle inner-tube and cut out the valve section. It will have either a Presta or Schrader valve. Silicone rubber sealant would probably be best for fixing it into the rocket.
netbus (author)  AndyGadget8 years ago
hay good idea! i will try it. i think you will get "best answer" from me. good job!
netbus (author) 8 years ago
well, actually i mean the air goes out from the pump. its not build for high pressure. a simple ball pump. when i attach it to a ball, you can hear the air leaking.
jtobako netbus8 years ago
Take the pump apart (if you can) and see where it's leaking. You may need to fix a rough spot or make the spring that holds the valve a little stronger. Or you may need a different pump.
netbus (author)  jtobako8 years ago
its not leaking.(i think). its just not built to hold air. i mean, its a cheap pump, the only way to keep it not leaking is to pump fast.
rickharris8 years ago
NOTE when you attach the air line the tyre valve will be opened and no longer a valve.

You need to read makezine blog more often :) will answer everything you need to know about water rockets.
netbus (author)  rickharris8 years ago
yea i know that site. i like it. but i didn't find anything there.
orksecurity8 years ago
If you really want a one-way valve: websearch "check valve".