Potato cannon efficiency?

I created a potato cannon that only has straight pieces of PVC.I have seen other designs where the combustion chamber is wrapped around 180 degrees with two elbow pieces thus making the cannon more compact.  Does anyone know which design is more efficient as in terms of launch power and speed?

ilpug6 years ago
Definitely the straight design. Ideally, you want a rougly 3/1 chamber to barrel volume ratio, with as little internal surface area as possible. Adding bends to the gun will increase the interior surface area, therefore decreasing efficiency.
onrust6 years ago
Use a copper barrel. Solder some fins at the end of the barrel. When you push the potato in and it hits the fins, give it a bit more in and make it tight..
Straight, always. Bends are very lossy.