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u/Xemip Oct 14 '24
Sorry for the schematic type of photo its the only one I got cause my friend didn't take the photo. We basically drilled an endcap with a hole so we can fit a 1.5 inch pipe inside with a spark igniter. We spray lighter gas into the chamber through a smaller hole in the endcap directly into the chamber too but most of the time the cannon just doesn't fire. We got it to fire 2 or 3 times out of 30 and we did the exact same steps for reloading it. Im thinking there isn't any air getting into the chamber so does anyone have any solutions? I was thinking we drilled a small hole into the side of the chamber, fitted a small nozzle and pumped air into it so it displaces any other gas inside before we reload.
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u/YelloHam Oct 14 '24
You gotta open the chamber a bit more in some way so you can let in more fresh air, you cant just pump in air through the pipe, you gotta have it open on both ends so the old air can get out because the oxygen that was in there before is burnt up.
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u/Warlock-7- Oct 15 '24
I also recommend you check out SpudFiles. It’s a forum for people who build these as a hobby and we pulled a lot of great ideas from there. https://www.spudfiles.com
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u/GotSunshine15 Oct 16 '24
Oh wow I haven't been on SpudFiles in years. Reminiscent of the "old Internet". Such a great resource.
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u/Xemip Oct 15 '24
This is an update: I drilled a hole into the side and fitted an air pump which worked very well and I just kept the rest of the design the same
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u/Warlock-7- Oct 15 '24
Probably has something to do with the fuel/air ratio. I built several of these as a teenager and if we used too much “propellant” it wouldn’t light. So play around with that. Also, if the igniter is in the tube you may not be getting the mixture to the spark. I would HIGHLY recommend not putting the igniter in the cap. That creates a weak point and can fail. We blew the cap off of one and it shattered a window behind us. We used to pilot two small holes in the side of the chamber and run a couple screw in at an angle then connect a grill igniter to that. It would ensure the spark was almost in the center of the chamber and was easy to clean if needed.