I am doing this for a project for physics worth 600 points. We built what seemed a pretty solid cannon out pvc however when time for launching came it didnt do anything. we are using a bbq igniter and i've felt the spark so i know its working as the igniter we are using starting fluid from autozone. Pleaseee helppppp this needs to be done by next week!!!!!!!!
Posted: Thu Dec 06, 2012 5:54 pm
by jackssmirkingrevenge
Fuelling is probably the issue.
Have a look at this:
[youtube][/youtube]
Actually calculating the amount of fuel you need and injecting the correct amount will also mean you're doing it more scientifically rather than "spraying and praying" and should get you more points
Posted: Thu Dec 06, 2012 6:03 pm
by jsefcik
are you venting it between shots? are you watching how much you spray in?
only do like a 2 sec shot and then try, if not, open the cap let some air in then try
Posted: Fri Dec 07, 2012 2:57 pm
by jimmy101
Also check that you are actually getting a spark inside the chamber. Just because the piezo will zap you doesn't mean it is jumping the spark gap.
But, what jack said. Issue number 1 is that you have to use the right amount of fuel. Too much or too little fuel won't ignite. A syringe is a cheap, simple and very effective way to get the right amount of fuel.
A chamber fan, or waiting a couple minutes between fueling and firing, will also insure that the fuel is properly mixed with the air in the chamber.
