New exploding 40mm Concept
 

THE IDEA:
Pictures will be below :)
I have been designing this little project for a little while now and was hoping to gather some feed back about its practicality and to see if there was an actual want for such a product some time in the future. I have yet to make a prototype and I am still working out the materials that I am going to build the 40mm out of so by all means if you have suggestions feel free to make them I am totally open to Ideas. The grenade itself is designed to fit into either a mid to long sized grenade launcher (such as an M203) or a shoulder fired air powered rocket launcher. It must have an external source of propulsion (like a nerf rocket needs a gas 40mm shell) to be fired. The grenade is designed to be extremely light because of the risk of bodily harm on impact, for this reason the grenade is composed of light weight materials and features an airbag to cushion the impact (It also serves as the firing mechanism). On impact the air filled bag on the front of the grenade will compress causing an increase in pressure within the grenade. This pressure change will cause the bbs to be launched from all sides of the grenade. This design will be totally reusable and requires no re assembly other than the addition of new bbs. The cost I that I pan on building this grenade for will most likely be less than $20 a pice.

THE PROBLEMS:
My design has a few issues which need to be worked out.
1. The grenade is made out of rubber which tends to rub and create a great amount of friction when moving, this means that I need to coat the grenade in some sort of lubricant or material that will allow it to slide easily form the launcher. Right now my idea is a spandex outer sleeve.
2. Right now the only way to fire the grenade is with existing 40mm grenade this greatly reduces the potential barrel length that may be useable by the grenade (I need to find a better power source)
3. materials I need to find a rubber like material that is easy to form and relatively cheap.

Any and all ideas are appreciated

-DAN

I love how it's a rocket.

I think you'd need a pretty high velocity to get the bb's actually shooting out hard enough while being light too. VERY interesting concept though. Have you considered having a small co2 cartridge inside the shaft of the rocket? Perhaps upon impact it could be released and you'd have a much better velocity behind the bb's regardless of the impact speed of the projectile. This would allow for mortars and everything else to use your design. That and it'd be more dramatic and kool :P

Note that I'm not (yet) a mechanical engineer or whatever, but reading this is what I'm thinking:

1- While working for the "air cushion" idea, wouldn't having an empty head cone cause a flight stability issue?

2- Do you really think that this "over pressure" created will be powerful enough and -especially- happen fast enough to actually disperse the BBs to be effective?

3- While improving flight stability, having rotation fins will cause drag, thus reducing its practical range.

Also, probably that to have enought pressure to get the "warhead" to go far, it would be best to use CO2 shells. Also, a little suggestion: as AI has done with their Tornado grenades, these are bright colours makes it easier to find them. And you might know that AI are actually working on their own project similar to that one. It was shown in the news section of this website, not that long ago.

Actually that was may original Idea but it got flat out rejected on my local forum due to wight issues. A grenade with a full Co2 charge would have to be significantly stronger and would weigh much more this would reduce range or increase the chance of injury to likely.

All ideas noted. Yes I have considered all of the fowling this is why materials are so key. The nose cone issue is something that I have considered in great detail for the very reason of a premature collapse on the initial acceleration of the grenade I figure if it can survive that force we should be dandy during flight. As for the impact nose cone pressure problem, I will have to see how the prototype works, same goes for the range. I am trying to keep as light as possible keeping in mind that I can always add weight but I can't necessarily shave more off.

-DAN

interesting idea but I'll wait for AI's 40mm

YouTube - Our promo video shown at the Japan BlackHole show!

Hate to burst your bubble, but if your shooting a rubber head out of one of those things and some one gets hit, thats like getting kicked by a horse. You could probably break ribs or at least leave one very nasty bruise. Riot squads use rubber bullets to break up protests and have had incidents where people have been hit in the head with these and died. The grenade will be travelling slower but would have more mass behind it when it makes contact. One alternative is to use a nerf foam head kinda like the footballs which might make your project a little safer. The only problem you have there is that the front end would be the lighter end causing the projectile to flip around so that the tail is pointing at would opponent. From my perspective Im not really sure how this could work. The head has to be soft to that if by chance it hits someone it wont hurt. But at the same time the head has to have enough mass to that it doesnt spin out of control. These are just my observations but all the power to you if you can make it work.

I have seen this and think it shows great promise However the AI grenade requires propane to operate thus will have a great deal more wight. Increased weight = decreased velocity for safeties sake.

The entire concept is made out of nerf like material minus the nose which is a rubber membrane holing in air and the body cover which is also a thin rubber membrane.

You haven't even looked at the design have you? It's not a rubber head it's completely empty, just a void of air, hardly any mass at all too it.

My thought would actually just be a modification to your current one for impact propelling the bb's. I'd use the energy to push a cap to burst the seal on the co2. I don't see it weight much more and you'd still have your "airbag" Very cool designs though. I'm certainly following your work.

you will need to aim the BB's feed path upwards when the rocket lands. otherwise the BB's will shoot out straight and drop a foot or two from the rocket.

another reason I say that it will only shoot a few feet is because you'll need to keep the weight down for safety, thus having less mass to create enough pressure to fire all those BB's far enough to be effective. overall lighter weight might also make the front 'air filled bag' ineffective because to light will cause it to not land nose first all the time.

adding a gas source on board the rocket to propel the BB's on impact will greatly increase mass making it unsafe. finding or building a small gas reservoir that is light enough might work but then again, the effective range will be limited.

it's an interesting idea but won't fly. please take my comments as constructive as I'd love to have a true 40mm that 'explodes' on impact or even in flight.

I'm not sure if that would work since there's still quite a bit of energy needed to burst that cap... I don't have any on hand though, so I may be wrong.

However, since there would be quite a lot more pressure, thus needing stronger materials which would add more weight, needing more padding to ensure it's not dangerous, etc...

@Coachster: If you've neen AI's work, then you've somehow got the proof that is possible

No offense taken I was looking for constructive criticism like this, after all it is just a prototype and does require obvious improvement.

I agree, I think airsoft mortars are much better in concept as you only need the high velocity while it's being launched UP on it's way down it'd reach terminal velocity anyways. The tornado ones don't seem too dangerous though. I'd still feel relatively safe on the feild with these if the same rules were applied to them as they are to hot guns. IE no noobs using them.