Ok so u might be wondering thy yet another potato gun design here on indestructibles. Well this is not ur typical spud launcher but its also not the most advanced granted it will evolve into one by the time its finished.
This gun is less than half the sive of the final gun with only a 1" barrel ( the finished project will have a massive 3" barrel), but thats ok because its only realy for test perpouses. Test perpouses? U might ask, and the answer would be most defiantly due to the fact i have never seen all the "advancements" that will be in the final gun.  Heck i haven't seen some of the mods im trying to cram into this one gun.
First off u will notice it has 2 combustion chamber let that sink in for a sec....... yes its a crazy cool idea... little harder to make work. but that is what this wos fore after all. im not going to lye and say this is the most BA potato cannon ever but i will say it has the potential to be one of the most extreme guns ive seen. (yes even this small prototype) I can say this because launching from just one chamber i can put grapes thru my chain link fence and about 50 yards onto a wooden fence and make them dissapear.
The reason i say only one chamber is because i have had issues getting constant fuel supply to both chambers usually ill have one chamber way rich and the other spot on. i have had a few test fires with both chambers firing correctly and when they do the lack of barrel is disturbing. (with the 2' barrel it still produced a 1' flame out the end with just one chamber about dubble as u would expect with both chambers) so with all that sad i have the instructions for the small prototype here i will be building a larger one with all the components of the big one next ei, metered propane, chamber fans, support system, and a full length 0.6:1 c:b barrel. all this will be to see just how impossible for me or possible the full size gun will be before i actually make it.
With all that sad if yall do make this gun please share ur experience with me and maby we can make this a nice little potato launcher that can be made for under $50 (so far ive spent only $30 on mine)

Step 1: Parts List

ok so u have shown a little intrest in this project so now ill let u know the causts and parts list
all these parts were sorced from my local home depot prices are ea. (and total per part w/ total at the end)

1 - 1" non threaded t                                             0.62   (0.62)
2 - 1" threaded 90 deg elbow                             1.21   (2.42)
2 - 2" cuppelings                                                  0.86   (1.72)
2 - 1" non threaded 90 deg elbow                    0.48    (0.96)
2 - 2" close out caps                                           0.82    (1.64)
2 - 2" close out cap adaptors                            1.18    (2.36)
2 - 2" flush mount 1" adaptors                          1.78    (3.56)
2 - 1" * 24" pvc pipe                                             1.67    (3.34)
1 - 2" * 24" pvc pipe                                             3.70    (3.70)
1 - battory opperated grill ignitor (walmart)  17.65  (17.95)

                                                                               total     (38.27)

i origonaly sorced a solid state grill ignitor from home depot but before i even had the spark gaps adjusted the cheap thing busted so i ran to walmart witch wos closer and cheaper and sorced a battory opperated one for the replacement caust amlost of the solid state one from home depot

its important to try and use solid core pvc i cant stress this enouf ive made about a dosen high power spud guns from this stuff and never once had a fracture or miss hap due to falure of the pvc
ya i cant type for nothing next one i will have my wife go over as far as all that goes. Well honestly to answer u about the 2 chambers ive just never seen it!! I like the dual chamber because the chambers act like a stand for the gun that way i don't have to always hold it to fire it. i have increased the barrel length and it has helped out a lot so im going to stretch it once more. this build in particular had 2 reasons, 1 to find out if the dual chamber would even work, and 2 to see just how i would have to measure the barrel and chambers, ie does the pluming get calculated with the chambers or barrel. It turns out the pluming will need to be measured with the chambers.<br> From the innital tests the dual chamber seems to be more of a hastle without the propane meetering and such but the netx prototipe will clear that issue up.<br> The project as a hole has a few goels to meet<br>1. it must be capable of shooting a 3&quot; dia object to about 200 meters<br>2. it must be as compact as posoble in its broken down stage<br>3. i must be able to fire it alone with no out side help, ie no one helping to hold it or a stand to hold it<br><br> so the project does seem to be on track the next build will actuly be a dual 3&quot; * 1.5' chamber with metered propane and interchangeable barrels and maby (depending on funds available) a angle adjust for the barrel<br> this stage will be in 2 phases. first phase will be barrel interchangeability and the effectiveness of different but still mathematically correct barrels. the second will finally introduce me to metered propane and introduce metered propane to the project.
great idea, and great build, but i have several things to say: <br><br>1. you need to clear up the spelling and typing a bit. im not much of a grammar freak, but it does bother me when spelling gets in the way of telling me about an awesome project like this one. <br><br><br>2. why two chambers at all, why not one big chamber? it seems like all the extra plumbing is just extra space to be filled. keep in mind that the magical ratio states that there is a certain amount of barrel for a certain amount of chamber. this is an interesting concept, and i recommend you another cannon to test it's effectiveness. build a cannon with one large chamber equivalent to the two chambers you have now, and the proper barrel length according to the magic ratio. test this cannon and the double chamber one in identical conditions. which fires the best? i am honestly curious to know.<br><br>3. i reccomend a change in fuel. pretty much any kind of hair laquer or spray containing dimethyl ether is the ideal fuel for potato cannons. <br><br>4. safety rant: NEVER USE PVC. USE ABS. PVC SHATTERS (as you said) AND ABS TEARS. I KNOW ITS HARDER TO FIND EQUIVALENT PARTS IN ABS, BUT SAFETY IS WORTH IT!<br><br>all that being said, great project, and i hope to see more from you in the future.<br>DAE (ilpug)