D4 - French air cannon - caliber 12mm

[suburban spudgunner]

I love these realistic types of guns. They seem to be pretty popular coming from France...

[Biopyro]

I had a look at the eurospudgun forum, but most of the cannons on there are created by people who are experienced here. I expect to see good quality from you, BTB and sniper hero. On the french forum on the other hand, every gun is something I would expect to see from an experienced member around here.
Perhaps the fact that more dutch people speak english means I see your cannons more here, or maybe the showcase section in france is moderated, but you have to admit, they are putting out some great cannons.

Despite mostly not having access to the same literature as us (because of the language barrier) they certainly seem to have advanced many of the same ideas. It's a lot more popular in france than I thought, possibly more so than in england!

I am just going to test the duct tape theory now...

[Xtazz]

Well, to explain you the French forum, there are 2 sections

1- Moderated : the hall of fame : the bests airguns
http://patator.frbb.net/patator-a-air-comprime-f19/

2- Not moderated : The free for all : every airguns ( from the crapest to the best ^^ ) are welcome : http://patator.frbb.net/vos-pacs-personnels-a-vous-f9/


We tried, months ago to open an english section, but sadly no-one ever posted in it. We made it after being approched by a German forum wich wanted to link our databases ( refused ).



Edit : be carefull using the duct tape on coke bottles. Some bottles canexplode at 4Bar, others ( we use german bottles ) can go up to 10 Bar.
You have absolutely to protect yourself form explosion ( hurt + sound ) when you are testing it.
You'd better try tu put +15% pressure in the tests, than when you 'll use it for real ( security margin )

[Biopyro]

Aha! that would explain why I thought every cannon was absolutely superb!

I have done these tests before, but never with duct tape, so I am wearing earplugs and safety goggles and gloves. I know it's loud!

Non fizzy water bottles go at around 4-6 bar, wheras fizzy ones go much higher.
500ml bottles do not explode at 180psi (my maximum)
1.5l bottles go at 150psi
2l bottles go at 120psi (they are LOUD!)
I have yet to try 3l bottles.

I am going to test a 2l bottle with tape.
I expect the tape to raise the pressure to around 160psi, as it will prevent it swelling, which is the precursor to the explosion.


EDIT: Well yeah, you were right! took it up to 11bar no problem. The bottle swelled a small amount, and the bottom buckled but nothing! When I got to 11 the pump head of my pump kept coming off the schrader. I tried a few times (so it was cycled between 5 and 10 bar about 4 times), but couldn't get it to stay on. I then threw a brick at it, which it took very well.

I placed it on some bare earth at around 120psi and threw a garden fork at it (I had become a little bored of the pump popping off by this time!). The fork dug into the ground like there was never anything there, and the bottle went BOOM!
As usual it split down the side with a great concussion fairly "safely" if you can call it that.

[Xtazz]

Haha

Did it explode after higher pressure than without the duct tape ?

[Biopyro]

Nope, I couldn't pump it higher than 11bars because my pump kept breaking.

It never normally holds 11bars so you were right, but in the end I had to pierce it with a garden fork to make it explode!

Edit: I noticed you cover your face in the video carefully. Is having an air cannon illegal in france?

[ALIHISGREAT]

Wow french cannons always seem to be clean and well built! (and your english isn't too bad either )



@ Bio i've toyed with the idea of fibre-wrapping a big drinks bottle a la paintball tank... but i've never really had the motivation to do it, i think it would make a good chamber though.

[Biopyro]

I agree, it seems fine, wouldn't be taking it past 100 though really, as that's when the bottom started to swell I think. Repeatedly stressing the bottom might cause a blowout.
I think 2 or 3 epoxied into fittings in the same system would make a good high volume reservoir for a semiauto gun or a refill station would be good, but you'd have to not mind the relatively low pressure. IMO they aren't great for single shot guns because the opening chokes the flow badly.
If you could easily just screw them into a pressure rated system it ouldn't be so bad because you could take them higher once, then discard them.

[Xtazz]

Well, I prefer proctect my face from being delivered in the net because I don't trust/believe in the France's police...

We live in a high security/spying country


@ALIHISGREAT : thank you !

[cleetus]

nice air cannon

[Tony.Knaak]

I am very impressed. The extra work you put into the stock is impressive.

Do you plan on finishing it? By finish I mean stain, clear coat, or paint the wood.

[Xtazz]

Little update from the D4


We've reduced the vidth of the stock ( gained 1.5cm )
With a little paint it gives us IT :








I'll soonly use a fire extinguisher at the place of the 2 bottles. It will go up to 25Bar !

[al-xg]

Nice
I like the reloading action.

I think you'll find France isn't that bad in terms of surveillance compared to other countries.

JSR that was beautiful.

Bon je vais plutot commenter sur le forum francais, j'ai vu "french" et forcement je me suis senti oblige de lire le topic
Les test de Biopyro pourraient bien interesser les membres du forum Fr.

[Biopyro]

I see my name but Je ne comprende pas!

The test I did would be interesting for the members of the french forum?

Anyway - it looks even better now!!!
How many shots will you get out of 25 bar from a fire extinguisher?

[LeMaudit]

Bon je vais plutot commenter sur le forum francais, j'ai vu "french" et forcement je me suis senti oblige de lire le topic Wink
Les test de Biopyro pourraient bien interesser les membres du forum Fr.

Yup Biopyro, you speak French see ?

full translation:

Okay, I'll rather comment on the french forum, I've seen "french" and obviously I felt compelled to read the topic
Biopyro's tests may interest the French forum members.