How much would it cost to make a....

[Pooper]

How much would it cost to make a spud cannon that could fire approximately 350 yards? I am new to making these and am wondering what ranges are like and costs. I am looking to make one that can shoot about this distance though.

[frankrede]

350 yards?
You can make one that will shoot 100 yards pretty cheap, but 350 yards doesn't come easy

[jackssmirkingrevenge]

In order to get that sort of performance while keeping costs low, you're best off building a medium sized combustion. This means you can use lower rated piping that would be the bulk of your expense, while items like a chamber fan and ignitor can be scrounged from scrap.

Have a look through the Combustion Cannon Showcase for inspiration - with features such a long barrel, chamber fan and a way of accurately metering propane into your chamber, as well as appropriate projectiles - ie more towards golfballs than the vegetables that give spudguns their name - that sort of range should be within reach.

[starman]

A spud projectile on just about any cannon will not = 350 yards. 200-250 is going to be about the limit no matter what. The problem is drag.

Getting golf balls and other hard ammo out 350 is pretty easy, just not spuds.

[jackssmirkingrevenge]

A spud projectile on just about any cannon will not = 350 yards. 200-250 is going to be about the limit no matter what. The problem is drag.

... and the fact that potatos tend to vapourise if fired above a certain velocity

[starman]

A spud projectile on just about any cannon will not = 350 yards. 200-250 is going to be about the limit no matter what. The problem is drag.

... and the fact that potatos tend to vapourise if fired above a certain velocity

Oh yes that too. BTW, what's the magic deal with 350 yrds Pooper?

[jackssmirkingrevenge]

350 yrds Pooper?

That's a LOT of intestinal pressure

[brogdenlaxmiddie]

350 yrds Pooper?

That's a LOT of intestinal pressure

Dear God I almost died laughing at that. Your hilarious JSR.

[hi]

with a good tail wind not a whole lot.

[Pooper]

Well I am basically trying to out do my friends cannon which goes about 300, I'll look at combustion cannons.

[starman]

Well I am basically trying to out do my friends cannon which goes about 300, I'll look at combustion cannons.

Get yourself a 1.5" longish barrel 6' to 8' or so with a standard 4" 12 - 15" long chamber. Anymore power or a burst disk would just vaporize the potato. Your best bet for getting real distance with a potato is with a long barrel.

I'm dubious about your friend's 300 yrd potato claim. I would be asking for proof.

Also, out of all the Merriam-Webster Unabridged dictionary available to us english speakers, may I ask what came over you to choose the particular ID that you did?

[Ragnarok]

Well I am basically trying to out do my friends cannon which goes about 300, I'll look at combustion cannons.

Like Starman, I'd consider that claim very dubious.

Any projectile that had truly been fired that far would be hard, if not impossible to actually follow through the air.
I have cannons I've proven can fire things that far, but you'd be damned to see the projectile in the air, they're that fast.

How was the range determined? No guessed range is proof, as most people over estimate ranges by a factor of at least two. - even with my range estimation experience, I wouldn't consider any of my guesses hard proof.

[Hotwired]

We had a natter on the chat about how larda could check the range of his cannon when HGDT guesses the projectile will land up to 20 miles away.

Nightmare trying to locate a 20mm projectile at that kind of distance even if it did produce an indicator on impact.

[Ragnarok]

... when HGDT guesses the projectile will land up to 20 miles away.

I have a feeling that the HGDT estimate will be off a bit because of experiments I've done on the supersonic model of GGDT comparing it to my LRC (which should be sound), but I don't know for certain which way (I'd guess high).

Anyway, because of the actual curvature of the earth, the dart's impact would actually be over the horizon, which even for a tall bastard like me on technically flat and level ground is still only about 3 miles off.

[noob of noobs]

Could you encase the potato in a big @$$ dart? Might improve aerodynamics and general flight path.
Do you have to use combustion? I'd recomend you try a pneumatic or a hybrid since they trump combustion in power and range.
Also, prices depend on where you live. As many will happily remind you of, pipe prices are cheaper in the US, and you can't even get PVC in many countries.