SpudFiles

What was the approximate cost in materials? Seems like quite a bit.

POLAND_SPUD wrote:I agree with jsr on this

I agree with jsr on this

I agree with jsr on this

getting mix to ignite isn't easy... and it's not that difficult to source tanks that are rated to more than combustion pressure of say 20X mix

Yup... though to be honest I really don't think that's necessary. The benefits would be tremendous, it really would just be a question of alternating between opening a single valve and ignition, dead simple.

I wonder if a tank-style bore evacuator would work:



... though really if you're injecting air and fuel, you don't really need to vent the chamber.

If this is (kind of) the holy grape

Available on Amazon

-F-A-K-K-

Stands for Fully Automatic Kartoffel Kanone, but sounds like the sort of noise a seagull would make before slamming into a cliff

I wonder if a tank-style bore evacuator would work

I doubt there is need to complicate something we haven't got to work ourselves yet

jackssmirkingrevenge wrote:

ramses wrote:We call that a bomb.

Let's call it a bomb.

I realize that accidental ignition is very unlikely, but I would recommend something that might be able to take the combustion pressure (like a 20oz CO2 tank), and something that has a controlled over-pressure mechanism (again, like the burst disk on a CO2 tank).

I was only trying to point out that IF it was ignited accidentally, it could be a bad day.

I was only trying to point out that IF it was ignited accidentally, it could be a bad day.

Only IF your pressure vessel can't handle the max pressure the mix can generate or IF it doesn't have a burst disk

About barrel evacuation:
Do you guys know how pulse-jet engine works???
These engines make about 50 to some 100 cycles per second by bringing the whole system in resonance. We just need a way to load the tube with ammo then......

Maybe store the ammo inside of the combustion chamber and release it piece by piece.....


About cost:
Tubing 10€
Arduino 15€
Display 15€
3 servos 50€ (but can be done with 10€ all together)
Plastic casing 6€
EDF + ESC 30€
Battery 10€
BEC 10€
Relais 5€
Ignition 15€

So about 150€/$. But can be easily made with half the price if you want to do more soldering and manufacturing...

Most of the parts I had on my stock, so it's mainly ignition, tubing and the casing I had to buy.

Right now I am little surprised that it is "that" expensive, but the fun is priceless...
Fun building AND the fun shooting!!!

POLAND_SPUD wrote:

I was only trying to point out that IF it was ignited accidentally, it could be a bad day.

Only IF your pressure vessel can't handle the max pressure the mix can generate or IF it doesn't have a burst disk

Thus my discouragement of using a 2 liter bottle in favor of a CO2 tank. I suppose you could consider the whole bottle a burst disk, but that still isn't good option.

ramses wrote:I was only trying to point out that IF it was ignited accidentally, it could be a bad day.

That's a fair assessment, however my contention would be that it would be less risky than, for example, a loaded spudgun would fire by accident, so no reason to be unduly worried about such an unlikely possibility.