What's not working with the ignition coil system. My coil had a short in it so it wasn't producing consistent sparks. When it did spark, the sparks were weak, too weak to ignite higher mixes. Sounds like a hindrance. Sure it's not the most compact system out there, but it's pretty cool and I have a...

Tech, if you are using UHMW, you don't need a rubber sealing face. As long as both the piston face and corresponding face are square and free of nicks or cuts, the UHMW will seal very well. I did this for my hybrid piston cannon and it never leaked. Of course, I had access to a lathe, so I was able ...

I hope to get a video up sometime in the next two months, but my camera is broken and I'm currently upgrading the ignition system. The camera flash igntion coil circuit has been giving me problems so I think I will build a <a href="http://en.wikipedia.org/wiki/Wimshurst_machine">Wimshurst machine</a...

now my only issue is to create the piston... For your piston, I would recommend using UHMWPE. It is impact resistant, it has a low density, it is self-lubricating with a low coefficient of friction, and it will seal against a sealing face by itself. This means that no rubber washers are needed. How...

The second design in the first diagram is exactly what my piston hybrid looks like (<a href="http://www.spudfiles.com/forums/bolt-action-aluminum-hybrid-piston-valve-al-50-t21259.html">link here</a>). My launcher does not use a pop-off valve, for a few reasons. First, I'm not sure that a pop-off in ...

How are you securing the two tubes to the gas transfer spacer thing? Are the O-Rings on those tubes? No, the o-rings are only on the endcaps and the piston. The spacer is clamped in place with six bolts and sealed with bike innertube gaskets. This is able to seal because the contours of the spacer ...

The bolt is very strong. And the frame that retains the bolt is strong as well. I have no concerns whatsoever about the bolt or frame breaking. Also, the pressure acting on the bolt will never be very high, as the golfball in the barrel starts moving at 3 psi, so the pressure acting on the bolt is f...

Moonbogg, thanks for the concern, but before building it, I calculated the shear strengths needed and I can say that at normal operation I have a safety factor of 13. I didn't just go to the hardware store and pick out some $0.89 bolts. I did my research and ordered proper shoulder bolts. That being...

The radio system is just a 49 Mhz Tyco Controller. It was just a quick little addition to allow for remote firing. I'm not sure about interference but there shouldn't be too much, because this cannon can only be shot in remote areas.

And jack, i agree and thank you.

Semi-auto would be nice, but I couldn't vent the chamber and refill in time to make it work, unfortunately.

As it is, I estimate that I can fire three shots a minute, which for a hybrid of such power isn't too bad...

This project started in January with this design, but I improved upon it after realizing that welding the chamber would significantly weaken the chamber. I then came up with the design below, which skirts the issue of welds by using bolted connections, as advised by Moonbogg. This design was made po...

This valve wouldn't fire, because the chamber would vent through the pilot. Also, there is no pressure acting on the barrel face of the piston, so even if you could vent the pilot without depressurizing the chamber, the piston would remain up against the pin/stopper. However, its always good to be t...

Like niglch said, a piston valve option in HGDT would be very helpful.

Also, would it be possible to model elbows and other elements that change the direction of airflow instead of an inline cannon?

How might you propose to redesign it? I would like to keep the general design, but I am open to some changes.

Moonbogg, how would I seal the chamber? O-rings? I am not exactly sure if a bolted construction would work for this particular launcher. Would you mind clarifying? Technician, I think that this configuration is easier to built and should be fine in terms of performance, but I agree that a larger pil...