First time potato launcher!

[Kennymester]

This is my first time constructing a potato cannon. Originally I was having a lot of trouble getting the right fuel mixture, but after adding a fan I'm having 100% success. The measurements of the cannon are 24in of 4in pipe for the combustion chamber and 48in of 2in pipe for the barrel. I inject propane through an 8in meter setup and use a grill lighter to ignite the mixture. The longest shot I've gotten so far was around 240 yards at a 45 degree angle. This week as well I will begin construction on a movable turret for the gun. The pictures below show my gun, the back end with fan, and a piece of plywood I hit at 100 feet. Comments are welcome.

[taytayswims]

such a clean gun and the damage is quite impressive for 100 feet

[brother361]

im pretty sure thats a dwv tee i think you would be fine but its alwasy good to be on the safe side

[Stifler69]

Wow man what an awesome potato gun !!!
You are so not a first time gunner from what I've seen here haha.
But yeah really nice gun, you should get some action of it on film.

[starman]

A little bit of a Rube Goldberg setup you have there. However, you've got it working consistantly and that counts for a lot. The propane canister looks funny hanging out there in seeming mid space.

Do something constructive with your battery holder and replace that duct tape with a hose clamp or even tie wraps.

Congrats on building a successful advanced combustion!

[Kennymester]

Wow man what an awesome potato gun !!!
You are so not a first time gunner from what I've seen here haha.
But yeah really nice gun, you should get some action of it on film.

No I really am I first time gunner. I just did a a lot of research and calculations before I did it. =)

I have to make it a priority to tighten up the design a bit. It's not too much of a problem to make some extra trips to the hardware store considering I work there. Lol

I'll see if I can get a video of it tomorrow.

[Stifler69]

haha nice well great job buddy

[mister pointy]

Great job on a first gun! Now that you have the gun working, you should try cleaning it up a bit. Tuck some of those wires away and replace your tape with clamps or zip ties.

Then, once you get your turret done, you'll have a great piece to call your first cannon.

[starman]

Also, what was your reasoning for the fan attachment/choke point design in the back?

[psycix]

Looks good for a first gun.

But it has some weird aspects, summed up as:
-Propane tank floating around somewhere. (you could possibly position that between the meter and the chamber)
-Meter pipe being very far away from your chamber. (instead of using a tee, you can just tap an hole and screw it directly in there)
-Excessive amount of fittings, weird reduction (and then scaling up again!) in chamber diameter near the back.
-Pink thingy on the barrel. (Not that it is wrong, but it looks weird)
All this is not wrong, its still a great gun. Its just, well, unique in its shape.

[Kennymester]

Well I can answer some of your questions. Well the back part of it was originally made so a threaded ball valve could be placed on the back. Long story short it didn't work that well. I already had threads there I had to use so I just made it interchangeable with other things. Also under the circumstances where the fan might break I can just make a new holder. I was also thinking in terms of a rocket when picking out the fittings so I though that if it was kind of like a nozzle in going from big to small to big it might give me better compression. I did fix the propane tank and turned it 180 degrees. As far as the battery holder and stuff I want it confined to the back piece so I think I'm going to keep it like it is. I might paint it in the future too, but I like the homemade look of it. I also ordered some parts for my next one as well which is going to be a golf ball gun.

[Radiation]

I've never seen any problem with DWV fittings, but it seems to be a pretty ingrained myth on this site that they are not preferable. I personally have used them with great success. extraordinarily nice for a first cannon! Congrats!

[psycix]

Okay, so now we know the story behind it all.
Good that you turned the propane tank around. I suppose it looks better now.
Any pic of that?