Double Wye

[PCGUY]

<div align="center">DOUBLE WYE

Provided By - Evildude

The heart of this gun is the 2 inch double wye. This combustion gun works differently from most. This gun has 3 spark gaps, one at the end of each chamber branch. Many spud guns have multiple spark gaps. It's been figured that for large chambers, this would help create a faster combustion since there's more than one place for the fire to start.

This gun uses 3 spark gaps for a different reason. Each spark gap starts a separate combustion that is isolated from the other two for the majority of the combustion sequence. Each flame front travels forward towards the breech. At the last moment, the three separate flame fronts converge all at once upon the breech.

My theory behind this concept is based upon what I know about combustion chamber efficiency in automotive engines. An efficient combustion chamber, such as a "hemi" design, has the spark start at the top of the combustion chamber, and the flame front travels downward towards the piston, which can be compared to a projectile.

I've noticed on many combustion guns that the spark gap is placed towards the center of the chamber, or many spark gaps spread evenly throughout. It would be hard to confirm unless I had several clear guns and a high speed camera, but I imagine that in a gun like this the combustion would be traveling in many directions. In a central spark gun the flame fronts would be going towards both the front and back, with 3 sparks there would be more separate flame fronts traveling different directions that collide with each other.

I wanted to create a design where the flame front would travel in just one direction, which would be the breech, but not have to travel a long distance to get there. That's how this gun was born.
It has impressive power for it's size. That's a 5 foot long sdr-21 1.5" barrel I have on it in that pic. I haven't precisely measured, but that barrel gives it somewhere around a .65 to a .8-1 C:B ratio. With no projectile it makes an unusually high and sharp sounding CRACK for a spud gun. When I fire a golf ball out of that bad boy, it makes very little sound and has a tremendous recoil for something of that size.

I have an old 2" x 2.5' long combustion gun I called the "boom stick" It has a single spark gap in the back and has almost identical displacement to my new WYE gun. However when I fire a golf ball out of it with the same barrel, I don't get near the same recoil or power.

Soon I plan to put a chamber fan and propane injection on this thing. I need to get a chronograph soon, I think I remember hearing of where I could get a refurbished one for around $40 right? Ok, I'm tired of talking now and I'm sure you are too. I'll keep you guys posted with what I'm able to do with this thing.

Provided By - Evildude</div>

[theexp]

reall nice.
I like how you really thought out what you wanted do and researched it.
Well it looks like you hardwork payed off.
BUT
How the hell do you hold that thing

[CS]

I like the holder for the gun.

[p8ntoer]

That's so cool! That must shoot significantly farther than a regular combustion spud, considering it has 3 chambers, all producing a huge amount of force. Mine, which has (1) 3 inch chamber and a 4 ft. barrel throws a shotshell out of sight, so i'm sure that this piece of combustion will throw a lot farther. Nice job...

[miniman]

Thats really cool, way different than anything I've ever seen!
I suppose you use a stun gun? a bbq igniter probably isn't powerful enough.
Is it really loud?

[darthtator]

Without a chamber fan is it hard to distribute the propane to all three chambers? Do you have any plans on building a bigger cannon with this same design? From what I collected, this gun gives quite a bit more power than your average gun this size, a larger version of this design would surely be a beast! All in all, nice cannon.

[toza]

that is totaly wicked i gues it would produce a pretty significant blast i'm pretty sure it would have a high chance of exploding though!!! i have a 1.6 ft combustion chamber but three would be way better
making a 5 inch combustion chamber hopefully will be alot more powerfull!!!!!!!!!!!!!
will give news on it once finished

[Thanatos]

that thing is way wicked man!! a friend of mine and i had devised a similar plan, but with only 2 combustion chambers. i kinda directed him from afar cuz i was out of town, so the dumbass bought some weak ass pipe, i have no idea what kind, and the thing blew up on him. luckily he was fine, and i will be trying to construct a beast of my own in the near future.[/b][/u]

[CHRISW_is_DEAD]

Definatly a good looking spud tosser. I can see how the extra two chambers would give this gun a nice little kick. What type of fuel do u use on this thing? And are u planning on making any improvements: direct propane injection, chamber fans, a stand?

[SpudStuff]

i have a 1.6 ft combustion chamber but three would be way better
making a 5 inch combustion chamber hopefully will be alot more powerfull!!!!!!!!!!!!!

they dont make 5 inch pvc pipe!
and besides it would be too expensive to buy a double wyh

[Viper]

I think he is talking about sewage pipe. that has a pretty large diameter. but I doubt that there are very many quality parts for such a large diameter p.v.c.

[PneuJose]

i have a 1.6 ft combustion chamber but three would be way better
making a 5 inch combustion chamber hopefully will be alot more powerfull!!!!!!!!!!!!!

they dont make 5 inch pvc pipe!
and besides it would be too expensive to buy a double wyh

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ohhh yes they do, even 12inch ive seen so far. i made a 6inch chamber for a pneu,from 6 to 2inches

[MrCrowley]

Yeah we all know they make bigger then 5", Ive seen some 24" next to my dads work.

[cody2]

God damn mine is a 4 in combustion to 1.5 in barell over under I hope to get a pic up soon