SpudFiles

Hi!
My project is now mature enough so that I can let you know about it:

generalities:
caliber : 6mm airsoft aluminium BB
canon length : about 550 mm
cartridge internal dimensions :
- diameter : 14mm
-length : 45mm
mix: 6 to 10
ignition : scooter ignition coil
expected performances : 365m/s 22 Joules

a picture of the 3D model (not finished):



Electrical sketches with two options (with or without reed switch):

i like this, but how will the cartrige eject, because he magnet pulls it, but there is not force pushing it up and out?

Looking forwards to see this happen

here you can see the key in grey, wich would eject the cartridge:
when the cartridge rushs back with the blow-back pressure, it will hit the key, rotate, and eject
the magnet is just here to pull back the cartridge in case of misfire, you must pull back quickly the lever so that the cartridge hit the key and eject

niceee, what will the cartriges be made of, try to take it to 200x mixes
that thing would pwn

(jk, dont go 200x without the proper steel, and recoil systems)

all is on the picture

the mix would be between 6 and 10
I hope getting to supersonic muzzle speed with 0,3g aluminium BB for airsoft, HGDT gave me results up to 380m/s

What is the material that is blue surrounding the brass tubing on the cartridge?

On your schematics I have a few concerns.

1) Reed switches do not have a high current rating that the coil primary requires.
2) You will want to have your "safety switch" at the coil primary +.
3) Do not try to "switch" the HV lead from the coil.

Conceptually it looks good but it will require some electro/mechanical refinements.

what is HV?
the blue is only the background color

nitrogigi wrote:what is HV?
the blue is only the background color

HV is "High Voltage" abbreviation.

I found a special switch for HV, that is able to switch up to 100 000 volts but, I won't try such a madness, I don't want to get 35000 Volts in my fingers

I wont put a reed because I didn't find a form B one

Looks good, what I've always wanted to make but never bothered Selecting the correct material for the seal is crucial if you want it to hold 150 psi of pre-ignition pressure.

the inner of the brass would be scratched so that the epoxy can be well held
I'll maybe replace it by glass fiber charged resin

finally I won't hold the BB with a rubber tube, I'll put a screwed "inner barrel" to be able to put a burst disk, because I want it to hold about 40 atm as pre-ignition pressure

nitrogigi wrote:I'll maybe replace it by glass fiber charged resin

Not really necessary for an endcap, fibres are more useful when you have a thin sheet.

it a resin with very short fibers mixed in it that improve the cohesion of the resin. I've already a pot of it, and I have to use it quickly so.....

this is going to be great

I maid a simualtion with solidworks, with mix10 and a burst disk holding 30 atm. It gave me a fire rate between 250 and 500 shots per minute, depending of the friction and of the spring stiffness