The Big One

[nick753159]

For my second gun, I decided to go bigger, a lot bigger. However, due to my relatively little experience and funds, I decided to keep it a basic combustion type gun.
What resulted?
A 2" x 108" (9 ft) barrel with a 4" by 24" (2ft) chamber, for an overall length of 11 feet. The C:B ratio is about 0.847
Its powered by hairspray and a grill lighter, nothing fancy at all.
Eventually, I would like to change it to propane powered, but for now, it works fine.
It took a while of playing around to even get it to fire, the chamber is so large that spraying an aerosol into it from the back is completely impractical. It won't go all the way back there before it liquefies on the walls. I have an old CPU fan, but its too big.
So, I spray in the propellant from a 1/2" hole that I had originally drilled for the grill lighter.
Ignition was also a problem, the lighter wouldn't light when it was in the chamber.
To solve this, I light it, it has a bendy arm, out of the chamber, and then bring the flame close to the hole.

I don't have any videos yet, sorry. It shoots probably about 100 yards and maybe more. Not good at eyeballing distances, just going on what my friends say.

[Hubb]

WOW!

Now for some shots.

[bigbob12345]

Wow thats big, kind of like my attempt a while back at a large combustion.
I had a 4 by 24in chamber but i didnt know about C:B's back then so I went with a 2in by 5ft barrel didnt work to great. I chopped it up a couple weeks ago.
that looks capable of more than 100yards id say more like 200-250.
Add propane metering to this thing and duel igniton and it will be a beast

[SpudBlaster15]

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[mauritstheman]

Wow that has a long pipe man do you have any damage pictures L)

Looks prety hot i made my 1st one too today and it was shooting like i huge bazooka omfg so cool spudguns

[Jared Haehnel]

Spudblaster has got it right looks awesome but the stats are way low on a gun that size. When you have a few more bucks I'd invest on a good chamber fan. Use ether instead of hiarspray it doesn't condense on the walls as fast and won't make a mess of your threads in the trap.

The chamber fan will mix the air the whole length of the chamber. that way you won't have to spray half way up the chamber. Then you can plug the 1/2 in hole... once you got all that done then you'll have a real cannon 8)

Wish my lawn was that green right now...snow gets old after awhile

[STHORNE]

wow, nice job

only thing..... you should consider making some supports for your long ass barrel so it isn't bent when you are shooting (should increase accuracy).

again, job well done 8)
--sthorne

[bigbob12345]

That looks capable of more than 100yards, I'd say more like 200-250.

Given the lack of a fan, the aerosol fueling, and most importantly, the 1/2" diameter hole in the chamber, it is unlikely that he is achieving a chamber pressure greater than 30PSIG, and as a result, the muzzle velocity (and thus range) will be very low for a launcher of this size.

Ahh I didnt see the thing about the 1/2in diameter hole in the chamber but if it didnt have that in the chamber Ill still stick to my previous assumption but i thought there was a chamber fan.
Ill read it again to make sure.
Edit never mind there isnt a fan.

[FordGtMan]

only thing..... you should consider making some supports for your long ass barrel so it isn't bent when you are shooting (should increase accuracy).

How would he do that if it isn't an over under cannon? Do you mean sleeve the barrel?

[MaxuS the 2nd]

Yeah, or run a bar down it, just to stop it from flexing.