the last "new BB design OMG ZOR" thread you will ever have to read... ok maybe not

[El Cactus Loco]

i know there has been a lot of discussion over the years about "sniper bbs" or whatever, and for the most part its all been trash... but an idea has just struck me and after thinking about it for a while, im confident enough to present it to the hounds (ASC) im not an engineer, im not a physics professor, im not a mad scientist, just a kid with an idea. be gentle, its my first time.

ok so here it is. we all know that the main thing that can make or break a guns accuracy is the hop up. what im proposing is a modification to the bbs to allow the hop to be more effective at putting backspin on the bb over long ranges. all modern bbs are fundamentally the same, a solid uniform ball of plastic. the mass is distributed equally throughout the bb. my idea is to make the bb hollow. allow me to explain my logic. the spin that the hopup puts on the bb is called angular momentum. angular momentum is the product of the bbs moment of inertia (a measure of an object's resistance to changes in its rotation rate) and its angular velocity (speed of rotation). the hopup is what controls the angular velocity, more hop increases the speed at which the bb spins. this spin allows the bb to fly straighter. moment of inertia, is what controls how long the bb will be able to continue spinning, allowing it to fly further. if the bb is made hollow but maintains the same weight as a solid bb, essentially what you would be doing is moving all that mass that was doing nothing at the centre of the bb out towards the perimeter allowing it to increase the angular momentum, therefore allowing the bb to spin longer, ie better accuracy over longer ranges. obviously this re-design means more than just making hollow bbs. they would need to be made of stronger plastic in order to have the same structural integrity a normal bb would, and would need to be made out of a denser material (HDPE?) in order to achieve the same weight as normal bbs, but other than that they would be identical and would be compatible with all guns unlike all other bullet shaped "sniper bbs".

now, this is just an idea (MY idea btw, no stealing. if i see hollow BB bastards anytime soon, someones gunna get a hurt reaaaal bad) and i have NO idea if it would actually work or how it would be made but i figure if we can put a man on the moon, we can make hollow plastic spheres. the only real concern i have is weather or not this would have any discernible or visible effect on bb flight. that is to say, bbs are pretty small, and im not sure that making them hollow would increase the moment of inertia enough to see any appreciable difference. but thats what you guys are for, what do you think?

[Bissa]

manufacturing them like that would be difficult especially in mass production.

[El Cactus Loco]

agreed, but everything new is
http://www.engineersedge.com/technol...posts/951.html
dont see how that couldnt be applied here, spray with some kind of high melting point plastic and use really low evaporating point material for the core. these metal ones are even being made in the size range we would need, 2-10mm

[Conker]

Don't take my word on it, but I think I remember reading that some brands do have air bubbles in their center. Most likely for this reason.

[xelamander]

why not put micro dimples on it just like golf balls have dimples? would that work?

[Cheesevillage]

This is a very cool idea...

I doubt there would be a large difference if we were to make current BBs like this. Before I finished reading your post I was thinking about larger BBs. One must consider air resistance gained (lost?) vs angular momentum gained once BB size changes.

I always pictured the spinning BBs to "grab" the air...which when one considers that thought seems ridiculous...yet when your BBs literally fall out of the air one can only assume the BB stopped spinning for some reason...

I would imagine (Loco) could do some calculations. When the volume available gets too small, consider http://www.engineeringtoolbox.com/me...ties-d_50.html


Sweet!

[Blackthorne]

BBBAstards already have a small bubble in the center on most cases. This was sto ensure even mass distribution, and not as a means of moving mass to the outer edge. There is a picture on the home page of the site if you wait for it to come up in rotation.

Seems like a good idea, but I wonder if the increase in range would be worth the extra manufacturing costs.

There is also a saftey factor here. If you make something more dense it trends toward becoming more brittle, add hollow to that and I believe the structure of the BB would lend itself to shattering.

Most interesting idea tho!

[AngelusNex]

Beyond a certain weight (.30 i belive) you can't make the bb any denser/heavier without switching to different materials. So this would require a brand new building material if you wanted to make bbs of this design at a weight any more than .20 . They would also cost allot... though as a sniper bb, up to maybe 50 shots per game max it makes little difference. Interesting idea however, and probably the most possible "sniper" bb I've heard to date. Cu dose on thinking of this.

[El Cactus Loco]

hmm, yah iv seen that bubble on KSCs before too, but i always just assumed it was a manufacturing defect/process side-effect. but i would like to see if i can get some hard numbers on this to see if it would be worth pursuing. ill ask some 4th year mech. engineers i know if they can do some finite element analysis on a 6mm hollow sphere, maybe in a few materials? and maybe even one in 8mm just for curiosity. i was also thinking (way outside the box mind you) that very thin walled brass (with low amount of zinc to decrease brittleness) sphere might work, as brass would be much denser than plastic so you could get as much of the effect as possible. that and most airsoft barrels are brass and brass-on-brass has self-lubricating properties if i remember correctly but might be wrong. brass is still a soft metal too, but i highly doubt that it would be practical simply for the reason that i wouldn't want to get shot with it, i don't think anyone else would either! and this is airsoft, remember? i think the only hobby with more lame/useless/hyped/expensive products/"accessories" is golf. but if the benefits are real and can be demonstrated... there will always be people out there willing to pay a premium.

the golf ball dimple idea is great! i don't know the exact science behind it, but i believe the basic principle is that the dimples cause the airflow to "ripple" around the sphere and decrease drag in the same way that a "boat-tail" does on a real bullet; by reducing the "wake" behind the ball. i wonder if sandblasting a bb (lightly) could have this effect? also there was a mythbusters a month ago where they tried to scale up the golf ball effect to a bowling ball, if someone can find it it might have some useful/practical insight into scaling it down as well.

gotta run now but this will be on the back burner today, keep the ideas coming guys

[AngelusNex]

Originally Posted by xelamander

why not put micro dimples on it just like golf balls have dimples? would that work?

Originally Posted by El Cactus Loco

the golf ball dimple idea is great! i don't know the exact science behind it, but i believe the basic principle is that the dimples cause the airflow to "ripple" around the sphere and decrease drag in the same way that a "boat-tail" does on a real bullet; by reducing the "wake" behind the ball. i wonder if sandblasting a bb (lightly) could have this effect? also there was a mythbusters a month ago where they tried to scale up the golf ball effect to a bowling ball, if someone can find it it might have some useful/practical insight into scaling it down as well.

gotta run now but this will be on the back burner today, keep the ideas coming guys

Golfball dimples would not work with the hopup. and may also allow air loss in the barrel around the bb as it is fired therefore lowering fps and if not very high quality, could scratch up the barrel bad.

[CDN_Stalker]

The 'Magnus effect', what we know as hop up, does two things: 1/ It generates lift on the lower front of the BB; 2/ It reduces the drag behind the BB, same as having a boattail bullet. Both of those is what makes the BB fly farther and straighter than if there wasn't any hop up.

I see where Cactus is coming from, he's suggesting more mass near the surface of the BB, getting the centrifugal force to make the BB spin more consistantly and longer. Unfortunately, velocity drops of rather quickly, and is hard to keep the momentum for increased range.

Way I see a BB's flight, you break it into three parts (call them thirds): 1/ The pure velocity coming out of the barrel, where hop up doesn't do anything and BB is the most resistant to air currents; 2/ The reduced velocity where the hop up does it's thing, still has speed and a decent resistance to air currents; 3/ The section of flight where velocity is so greatly reduced, hop up doesn't have as much of an effect anymore and the BB strays/becomes more susceptable to slight differences in air. All of the above just about every player has seen when shooting and watching the BB's flight path, if they actually WATCH what a BB does. Snipers are at top of the list for this, because we have to compensate for for where the previous BB went, based upon the air patterns in our area of shooting. It's really not something that can be predicted, not accurately, it's literally a test shot then the real shot.

Overall, I doubt a hollow BB with the same weight would make any difference, but it is a very neat concept though.

[Blackthorne]

Are there hop up rubbers that have textured surfaces to "grab" the BB better?

You are always going to lose energy to the hop up process but I figure more spin will compensate for the lack of FPS with a more consistant shot grouping.

[Amos]

Hop ups are a soft rubber, BB's are a hard plastic.

They grip very well already... unless you oil your hop-up

[CDN_Stalker]

Wash your BBs, that'll make the hop up rubber grab more.