FEAR

[Killjoy]

FEAR

Combustion Chamber
6" diameter sch 40 steel pipe, 63" long. Recommended working pressure 1100, burst pressure 3200 psi. Total volume approximatly 1809 cubic inchs (includes fittings and such).

Barrel
2"diameter sch 40 PVC pipe, 50 feet long. Seperated in 10' sections and connected together by modify couplings. Total volume approximatly 1884 cubic inches.

Ignition Source
Two car igniton coils connected in parrallel, which have a capacitor from a camera flash circuit discharged into them. The flash from the camera circuit is used as the switch to complete the connection between the capacitor and the igniton coils. This set up is able to produce approximatly 50,000 volts.
This is connected to a spark strip with 5 gaps, each one foot apart, evenly spread through the combustion chamber. These are mounted to a 1/4" steel rod which is mounted to a stainless steel 1" threaded plug and is screwed into 1" tee mounted on combustion chamber.

Burst Disk Set Up
A modified 2" steel coupling is bolted down with 4-1/2" steel bolts onto a piece of 2" sch 80 steel pipe welded to combustion chamber. Burst disks consist of 3 layers of duct tape with a piece of 1/4" plywood cut to fit over the duct tap. Other disks include layers of duct tape and pvc tape, duct tape and aluminum foil, and duct tape and pieces of tin cans (cut to fit).

Features
-Air and fuel metering completly controled electonically by operator; Fuel, Vent and Arm switches all have safety covers to prevent accidental switching.
-One switch operates the entire fuel meter system, flip it on till meter reaches 80 psi, flip it off and it dumps into combustion chamber. DO ti as many times as required for fuel/air mix.
-Large size allows more forgiveness when mistakes are made when adding air or fuel to cannon.
-Able to achieve velocities up to 2700 fps with a potato (still currently being debated).
All parts on combustion chamber rated to a minimum of 1000 psi.

Total Cost and Time Spent
$20 dollars for combustion chamber
$350 for valves, gauges, all fittings, pipe and barrel
$100 for electonics and parts for control panel
$100 for other stuff.
Total:$570
Spent over 100 hours welding, manufacturing parts, and putting everything together.

The only current pic of FEAR assembled. (I apologize for lack of size and clarity, it was taken with a cell phone).


The fuel/air metering system. Consists of 3 valves, two of which are
three-way valves (for the fuel meter and compressed air) and the one-way valve is for venting.


The control panel (front). Propane regulator and air compresser gauge are mounted on the panel. The three top switches are (in order from left to right): vent, fuel, and compressed air. All valves work off of 24 volts.
The toggle switch on the bottom is for arming and charging the capacitor, and the pushbutton is for firing the cannon (discharging capacitor into igniton coils)
The control panel consists of a 3/16" thick steel plate, and has the labels for each switch stamped into the metal

The main combustion chamber with everything mounted to it. Weighs close to 300 pounds. After nearly 3 months i got the bright idea of adding wheels, which allows it to moved by one person rather then two.


The burst disk holder.


The back of the combustion chamber. The large gauge is a 1-100 psi guage with 1 psi incrments, and is for measuring the correct amount of compressed air; the small guage is for measure the combustion pressure and goes up to 1000 psi (a check valve is used to retain the pressure after the burst disk has burst).
The 1" tee is connected to a 1" sch 80 steel pipe nipple welded to the 3/4" steel plate. This allows the spark strip to be slid in to the combustion chamber (and be located in the center) as well as the fuel and air to be put in. This design allows only 2 holes total in the combustion chamber, one for the spark strip, fuel, and air; and one for the barrel.


Damage to a 55 gallon drum using 2 golfballs as projectiles. The top of the drum is 3/16" thick steel.


Videos
(screwed up, must right click and open in new window or tab to watch).
Potato being fired at sheet metal (wood stopped penetration).


Two loosly wadded golfballs being fired at a steel drum (damage pic above).

[Redcoat]

That is an absolute monster!!!! That is an awesome cannon although i dont know much about hybrids that is just pure awesome. :toothy10:

[kleon11]

thats awsome gooooooood job although that proberly doesn't mean much coming from me but hey wot the hell WELL DONE

[Kenny_McCormic]

u have my vote for the hybrid catagory. how many x have you had it up to? i think it caould handle up to a 5 maybe 6 without exceeding the rating of the pipe

[Fnord]

First of all -since I havent commented on this yet- awesome.
Maybe you should take the whole thing outside to get a better picture.
second, Would 5 or 6x cause DDT in such a large chamber?

DDT seems to be a largly undocumented occurrence in spudguns. It would be nice to see what kind of pressures a DDT firing can generate, and what it really does to preformance. Another thing: how can you tell exactly when a DDT happens vs. a normal combustion? (other than the chamber grenading)

If we can safely harness the power of a DDT a new generation of spudguns could evolve *mad-scientist type laughter *

[Velocity]

This certainly sounds to be a very nice cannon, but I really cannot tell from the pictures. Like Fnord said, if you could take it outside and get some clear pictures of the chamber and chamber accessories, that would definitely be great.

[super spuder]

all i can say is "holy crap" that thing is just sweet. of what i can see of it anyways.

[Killjoy]

yeah sorry about the pics, i cleared out my garage and have some better ones, but my friend has my memory card with the pics and im trying to get them back. Ill try and take some more pics though, and see if i can get my neighbor to help me move it outside so they look better....

[demilus]

Just how much did this cost you to make? And how much did your dad help pay for it? btw, sweet cannon. I had about the same reaction as in the video... HOLY SH!T

[Killjoy]

Mid-way through the post i gave a price list and total cost, which was $570 dollars (evrything brand new would have been well over $1500 dollars).
My parents pitched in about $150 bucks, the rest i stole, killed for, and sold my self on the street to fat ugly women for...nah I'm just kidding, i had some funds from my job over the summer id been saving and i used those.

[frankrede]

Nice!
You definitively need more recognition for this.
As a matter of fact I plan on building a pneumatic one day and having a 100 ft golfball barrel for it! It might actually might be one of my cheaper cannons since it will use a ball valve.

So are you satisfied with this cannon?

[Killjoy]

thanks frank, and I'm looking foreward to seeing the day you nuild and finish that cannon.

I'm pretty satisfied, it works great but i really want to improve it aesthetics. Over the summer i'm planning on changing the pvc barrel for a sch40 2" steel one (same length), and then mount the entire cannon on a trailer for easy of transport (it will still come apart in sections), and have everything cleanly mounted on the trailer (propane, compressor, barrels, control panel, the works). I would also like to paint it some camo color, probaly matte black.
But unfortunantly i ran out of time for aesthetics, and could only present the cannon itself, which is still pretty damn cool...so its all good.

[ammosmoke]

All I can say is

[frankrede]

haha this cannon scares away noobs its so scary.
And the day I build that cannon is the day I decide to make a one day cannon.

A cannon that will be built on spot in the desert minus the chamber and valve setup.
and probably never be built again.
the chamber would have to be massive.
Hmm I might modify a old air compressor or water heater.

But like most of my projects it probably won't happen.

[Killjoy]

sounds good, its sadely funny though how so many ideas go un-pursude.

you know i just had this great idea, you know those propane transport trucks, you could buy a used one (they're made to hold over 100 psi because the propane is in a liquid state), attach a huge f*ckin barrel to that with a 12" piston valve and you got your self a cannon.
Just an idea for anyone with to much money and time on there hands.....