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sniperx2s

bullet shaped projectiles

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Ok before you start flaming me, I know this topic has been mention like a billion times and that you will probably have the urge to shoot the person who will mention it again... HOWEVER

after reading some of the topics involving BB's shaped like a bullet, no one actually gone into its theory and provided some math to back their opinions. all I see is "without hop up, the airsoft sniper rifle will have extremely limited range" however, the one thing I fail to see people state is the amount of drag a spherical object has vs. a bullet shaped projectile, and the mathematics to back up their statement. to start off, I would like to explain that a spherical object has A LOT of drag mostly because of the when the amount of turbulence generated behind the object behind the sphere. however a bullet shaped object limits the amount of turbulence to create a more laiminar airflow around the projectile. even though a bullet has better aerodynamic, it isnt the best. the best aerodynamic shape, is the airfoil. or the stereotypical raindrop that is wide at the bottom, and tapers to a fin point at the top.

 

after some research, I found that the Drag coefficient of a sphere to be somewhere around 0.5, while the drag coefficient of a airfoil to be 0.045. as you can see, a spherical object has a lot more drag than an airfoil shaped object. to calculate drag... forumual:

 

FD= 1/2pu^2CDA

 

where

FD is the force of drag, which is by definition the force component in the direction of the flow velocity,[1]

ρ is the mass density of the fluid, [2]

u is the velocity of the object relative to the fluid,

A is the reference area, and

CD is the drag coefficient

 

Area will remain a variable as I have no idea what the area would be

 

So drag of sphere=

 

Fd=1/2 (1.204kg/m^3)(500FPS)^2(0.5)A

 

which would be 75,250a (keep in mind area is still a variable)

 

Drag of airfoil

 

Fd= 1/2 (1.204 kg/m^3)(500FPS)^2(0.045)a

 

which would be around 6,772.5a

 

Now the amount of drag in a airfoil compared to a spherical projectile is about 11 times less. taking info from the ATP, the effective range for a spherical projectile with no hop up would be 80 feet, where as the effective range would be about 12 inches below the shooters elevation. Now we multiply that figure by 11, to get a effective range of 880 feet. Now 880 feet seems absurd, and thats because we left the variable for A blank. The surface area for a airfoil shaped projectile will be a lot more than a spherical projectile, most likely effecting the difference of drag between the two projectiles. which would mean the effective range of a airfoil projectile to be much lower.

 

 

Keep in mind that all this math could be total BS, and I only did this to prove a point that we shouldnt so hastily throw away some idea before going more into detail and get some hard evidence of its possiblilty

 

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Do a google search for "blade bullet"

 

Yes it has been brought up. And the system we have now is probably the best system.

 

To have a conical projectile you would need it to grab the lands and groves of the barrel. Which would mean some extreme pressures to get the projectile up to speed. And those speed are far to high for play.

 

But yes it has been brought up, but the ins and outs of it make it very usless.

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Do a google search for "blade bullet"

 

Yes it has been brought up. And the system we have now is probably the best system.

 

To have a conical projectile you would need it to grab the lands and groves of the barrel. Which would mean some extreme pressures to get the projectile up to speed. And those speed are far to high for play.

 

But yes it has been brought up, but the ins and outs of it make it very usless.

I was thinking putting spiral grooves on the bullet iteslf. not to put rifling in the barrel so to maintain the FPS around 500 FPS and to induce spin. and I have no idea what blade bullet is suppose to be

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I was thinking putting spiral grooves on the bullet iteslf. not to put rifling in the barrel so to maintain the FPS around 500 FPS and to induce spin. and I have no idea what blade bullet is suppose to be

You would have to make you own mags and feeder for such a shaped projectile. Also, if you are putting grooves and all on the projectile, that's a pricey airsoft BB...

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You would have to make you own mags and feeder for such a shaped projectile. Also, if you are putting grooves and all on the projectile, that's a pricey airsoft BB...

magazine feeder=shells to align bullets

 

no it would not be expensive. create 1st prototype out of CNC, then, create molding multiple molding. take molten plastic, pour into mold, wait to cool, remove mold, repeat. and before you kno it, lots of projectiles.

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Ok before you start flaming me, I know this topic has been mention like a billion times and that you will probably have the urge to shoot the person who will mention it again... HOWEVER

after reading some of the topics involving BB's shaped like a bullet, no one actually gone into its theory and provided some math to back their opinions. all I see is "without hop up, the airsoft sniper rifle will have extremely limited range" however, the one thing I fail to see people state is the amount of drag a spherical object has vs. a bullet shaped projectile, and the mathematics to back up their statement. to start off, I would like to explain that a spherical object has A LOT of drag mostly because of the when the amount of turbulence generated behind the object behind the sphere. however a bullet shaped object limits the amount of turbulence to create a more laiminar airflow around the projectile. even though a bullet has better aerodynamic, it isnt the best. the best aerodynamic shape, is the airfoil. or the stereotypical raindrop that is wide at the bottom, and tapers to a fin point at the top.

 

after some research, I found that the Drag coefficient of a sphere to be somewhere around 0.5, while the drag coefficient of a airfoil to be 0.045. as you can see, a spherical object has a lot more drag than an airfoil shaped object. to calculate drag... forumual:

 

FD= 1/2pu^2CDA

 

where

FD is the force of drag, which is by definition the force component in the direction of the flow velocity,[1]

ρ is the mass density of the fluid, [2]

u is the velocity of the object relative to the fluid,

A is the reference area, and

CD is the drag coefficient

 

Area will remain a variable as I have no idea what the area would be

 

So drag of sphere=

 

Fd=1/2 (1.204kg/m^3)(500FPS)^2(0.5)A

 

which would be 75,250a (keep in mind area is still a variable)

 

Drag of airfoil

 

Fd= 1/2 (1.204 kg/m^3)(500FPS)^2(0.045)a

 

which would be around 6,772.5a

 

The missing A brings both of those numbers closer together. The surface area of the airfoil is much greater than the sphere. And the shape of the foil would be very hard to adapt to be in a barrel. When you start rounding the edges, you are moving back to the sphere shape.

 

DeltaX = 1/2at^2

 

If there is no wind resistance stopping the bb, it will have dropped about 4 ft at 250 ft when shot 500 fps. This is the most ideal situation, but will never happen.

 

 

 

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The missing A brings both of those numbers closer together. The surface area of the airfoil is much greater than the sphere. And the shape of the foil would be very hard to adapt to be in a barrel. When you start rounding the edges, you are moving back to the sphere shape.

 

DeltaX = 1/2at^2

 

If there is no wind resistance stopping the bb, it will have dropped about 4 ft at 250 ft when shot 500 fps. This is the most ideal situation, but will never happen.

I understand the first part, because thats what I stated, but I don't get the second part... please explain

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I understand the first part, because thats what I stated, but I don't get the second part... please explain

 

Essentially, there needs to be some kind of lift to counteract gravity. Simply reducing the drag will not magically make the projectiles fly in a straight, flat trajectory.

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Essentially, there needs to be some kind of lift to counteract gravity. Simply reducing the drag will not magically make the projectiles fly in a straight, flat trajectory.

making them faster will. when I had my l96 a while back, and I accidentally lubed up my hop up. I went outside at shot it, and I noticed that it flew straight for a while, and then it just dropped. however, in a vacuum, it should follow a predictable arc. after it loses initial velocity, it will begin to drop. the rate of the drop will be the same, but you are trying to get the projectile to your target before it drops to the ground. having a more aerodynamic projectile means that the bullet will get to the target quicker, minimizing the effect of gravity. also, since its more aerodynamic, it will follow a more predictable arc to the target.

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Another thought, if the twist rate was changed on a barrel like the TK twist barrel, would it be possible to use it at higher FPS'?

you kno, I never thought about that. I only thought about making the grooves deeper. btw I have the tk barrel for my m4. love it. probably the best barrel ever made.

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To be honest this topics comes up about as often as the dimpled bbs. ;)

 

 

There has been some talk about the TK twist being made to help with higher fps. But Tanio Koba has the barrels patented, and when asked about making some with a faster twist, he said no. He really has no intentions to make them for the US market. As these barrels were just ment to be kept in the Japan area.

 

Being as this is their key market, you probably will never see one that is made for our higher FPS rifles.

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To be honest this topics comes up about as often as the dimpled bbs. ;)

 

 

There has been some talk about the TK twist being made to help with higher fps. But Tanio Koba has the barrels patented, and when asked about making some with a faster twist, he said no. He really has no intentions to make them for the US market. As these barrels were just ment to be kept in the Japan area.

 

Being as this is their key market, you probably will never see one that is made for our higher FPS rifles.

 

ahahahaha, it would be nice to have a TK for a 550 FPS sniper rifle.

 

 

anyways, ive got an idea of how to test this... actualy test this. step one: make a lathe step two: make a projectile in that lathe, step three, make plaster of paris mold, step 4: pour molten plastic inside, step 5: test... step 6: if everything works out, test it with UHC super 9.

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To be honest this topics comes up about as often as the dimpled bbs. ;)

 

 

There has been some talk about the TK twist being made to help with higher fps. But Tanio Koba has the barrels patented, and when asked about making some with a faster twist, he said no. He really has no intentions to make them for the US market. As these barrels were just ment to be kept in the Japan area.

 

Being as this is their key market, you probably will never see one that is made for our higher FPS rifles.

 

 

I didn't know that, so the barrels could be made to work with higher FPS then? It is legal issues that is stopping us?

 

It seems ridiculous that if TK could make what could be the best sniper rifle barrel out there and have a monopoly over it, he still wouldn't do it.

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I didn't know that, so the barrels could be made to work with higher FPS then? It is legal issues that is stopping us?

 

It seems ridiculous that if TK could make what could be the best sniper rifle barrel out there and have a monopoly over it, he still wouldn't do it.

this is getting a bit off topic...

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My bad, back on topic.

 

Plaster is a good idea just to try it, or even melting some plastic.

that was the basic idea, create accurate prototype first, create mold with plaster of paris, and then pour molten plastic inside the mold. although the bad thing about plaster of paris is that its a one time thing, so I might need to find a better mold. ive watched a show about how they make ferrari's, and the mold they use for the engine block is actually sand...

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that was the basic idea, create accurate prototype first, create mold with plaster of paris, and then pour molten plastic inside the mold. although the bad thing about plaster of paris is that its a one time thing, so I might need to find a better mold. ive watched a show about how they make ferrari's, and the mold they use for the engine block is actually sand...

 

 

I have heard of that before, however its probably not accurate enough to make projectiles.

 

I believe that there is some special putty to make temporary molds. And I have actually saved plastic bottle caps just for melting purposes.

 

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I have heard of that before, however its probably not accurate enough to make projectiles.

 

I believe that there is some special putty to make temporary molds. And I have actually saved plastic bottle caps just for melting purposes.

ahahaha, thats how companies make BB's... with molds... im not trying to make and market BB's im just trying to make a couple, and try to get a proof of concept. anyways, can I have ur plastic bottle caps? nah man jk. im actually gonna use PVC for the melted plastic and the first model that I will make on the lathe. I just need to make the lathe, then find a thick enough stick of PVC. and also, I could make 2 halves of the mold with plaster of paris, but then theres probably gonna be some leakage in between the two halves, and so I would have to sand it off. again im trying to stay as consistent as possible between the too pojectiles

Edited by sniperx2s

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im wondering what parts of the twist barrel are actually patented. A rifled barrel isnt something you can really patent. He just must have his own dimensions patented because its what he found to be best (TPI, barrel ID, groove depth/width, etc) at the 1 J mark. If its true, then we could setup our own for higher FPS applications without any legal implications. Someone should correct me if I am wrong on the patent matter though, I will probably end up looking that up tonight tho lol.

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after some research, I found that the Drag coefficient of a sphere to be somewhere around 0.5, while the drag coefficient of a airfoil to be 0.045. as you can see, a spherical object has a lot more drag than an airfoil shaped object. to calculate drag... forumual:
Quick googling tells me that the drag coefficient of a sphere can range from 0.07 up to 0.5. How does that affect the calculations? Our BBs could have a much lower coefficient than you're running numbers with. Then, since I'm not in the mood to really go look it up, but how does the coefficient of drag change for a sphere when it is rotating? I forget what happens, but I feel like it should decrease a bit, and as our BBs are definitely rotating moderately fast, that makes a big difference.

 

anyways, ive got an idea of how to test this... actualy test this. step one: make a lathe step two: make a projectile in that lathe, step three, make plaster of paris mold, step 4: pour molten plastic inside, step 5: test... step 6: if everything works out, test it with UHC super 9.
One could also see about getting a CNC lathe (or having a machine shop that had one make them for you) and just program the shape into it and make many of them without having to make a mold, which will have its own issues with consistency. Also, you can buy raw materials teflon in rods and just directly make the projectiles. It seems like it would be a very fast and easy process. You just need to find someone with a CNC lathe you can "borrow" to make a couple hundred. I actually plan on making my own test projectiles, though they won't be as identical as I'd like them to be, and I won't be able to fire them through a standard airsoft barrel, given the Teflon rods I got are slightly smaller than I'd like them to be. They do fit in a 5.64mm ID tube, so I'll be doing that at some point.

 

Just remember to get the right weight too, because I bet PVC is less dense than a .2g bb.
Use Teflon. It has a density of about 2.2 times that of water, and if I recall, a 6mm sphere of water is about the same density as a .12g BB (quick calculation tells me it's about .11g), so doubling (well, 2.2ing) that gives you something like a .25g BB. Teflon is easy to buy, and basically gives you a .25g BB equivalent. Then, if you're making a projectile that's bigger in volume than a sphere, like say a bullet shape or a teardrop shape, you'll add even more mass overall. PVC apparently is only about 1.4 times as dense, as is delrin.

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What do you mean by this?

 

Just remember to get the right weight too, because I bet PVC is less dense than a .2g bb.

yeah ill do that

 

I mean make a lathe as in, get 3 pieces of wood, one would be the base, the other 2 will have holes in it, with as close of an inner diameter of the PVC. attach the 2 pieces of wood into the opposite ends of the base. then hook up a power drill to the teflon rod, turn on the drill, and its gonna spin. take tools, and shape a bullet. after that create molding, pour molten teflon into the molding, and let cool, then repeat.

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There is a special tool that is needed to do the rifling in a barrel.

 

I am not sure what it is that is patented, but I remember him saying that some where. I think it was the rifled barrel in general for airsoft. Not to sure. But I am sure if someone over here in the states would make one, there would be a market. The one down fall is that they are FPS particular.

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There is a special tool that is needed to do the rifling in a barrel.

 

I am not sure what it is that is patented, but I remember him saying that some where. I think it was the rifled barrel in general for airsoft. Not to sure. But I am sure if someone over here in the states would make one, there would be a market. The one down fall is that they are FPS particular.

im not gonna have a rifled barrel. I have to figure out a way to put some sort of "fins" on the projectile so it will stablize in flight without rifling the barrel. thats my biggest problem. I need to make a way to accurately make fins around the first prototype.

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The idea, and production, of rifled barrels came long before Tanio Koba did, and simply changing the specifications to a preexisting technology would not be good enough for a new patent.

 

TK barrels use these grooves to control air flow in order to control the areas the BB bounces off the barrel. The only patent apparently registered under Tanio Koba's name is #5780762, which applies to a system to pull the slide of a GBB back to load a new round via connecting arm attached to the trigger (Hell of a trigger pull.).

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People have gone over the math before.

 

The main downside to the physics of the idea - formalities aside, is gravity, and the inherent low velocity of airsoft rifles

 

Without lift, a BB or similar projectile would drop 5 feet in under 200 feet, making the arch of the shot very extreme.

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People have gone over the math before.

 

The main downside to the physics of the idea - formalities aside, is gravity, and the inherent low velocity of airsoft rifles

 

Without lift, a BB or similar projectile would drop 5 feet in under 200 feet, making the arch of the shot very extreme.

I kno, I have thought about this before. thing is, if I can lob accurately, I would be happy. I realized that there is no way for an airsoft gun to shoot a flat trajectory, so, we need to lob it. with a aerodynamic projectile, the arch of the lob will be much more predictable, add this to the inherent accuracy of air foil projectile, means that placing accurate shots is possible, with practice of course. I will be testing this out some way or another, and I wont give up on this topic until I can get hard evidence that this isnt practical. airsoft isnt theoretic physics and shouldnt be treated as such

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I kno, I have thought about this before. thing is, if I can lob accurately, I would be happy. I realized that there is no way for an airsoft gun to shoot a flat trajectory, so, we need to lob it. with a aerodynamic projectile, the arch of the lob will be much more predictable, add this to the inherent accuracy of air foil projectile, means that placing accurate shots is possible, with practice of course. I will be testing this out some way or another, and I wont give up on this topic until I can get hard evidence that this isnt practical. airsoft isnt theoretic physics and shouldnt be treated as such

 

Understand though, that when the shot trajectory takes up that much vertical space, you start to run into problems like the scope being unable to zero at a particular range, and the field of view of the scope not covering the BB for it's entire flight. When you have that kind of arch, you need to start to think about the slant of the scope in relation to the bore of the barrel.

 

It's not impossible, it's just that it's a new thing that people aren't experienced with. There are a lot of logistics to work out.

 

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Understand though, that when the shot trajectory takes up that much vertical space, you start to run into problems like the scope being unable to zero at a particular range, and the field of view of the scope not covering the BB for it's entire flight. When you have that kind of arch, you need to start to think about the slant of the scope in relation to the bore of the barrel.

 

It's not impossible, it's just that it's a new thing that people aren't experienced with. There are a lot of logistics to work out.

I don't see much problem as to using a low power magnification scope with high diameter, let see, a 3x50 scope. also, being that the projectile will be rather slow, it wont be that hard to "follow" the projectile through its arc. I mean, fire it at one angle, and then slowly tilt the gun down as the projectile follows its arc.

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It sounds like you are thinking about needle-shaped plastic projectiles. I would suggest a plastic tapered rod with a "boattail" rear end and spiral-grooved front taper for a stable and accurate projectile. I DO NOT want to get hit with one. Nor would I aim it at you.

 

Assuming everything you are thinking works flawlessly, what is going to happen when your bullet-shaped projectile hits human flesh? Will it be allowed on a field?

 

Standard steel BB airguns are capable of far more accuracy than airsoft guns over the same distance. The difference obviously isn't projectile shape but rather projectile mass and velocity. Factors that come into play with an airgun that doesn't have to avoid hurting people - the steel BB can be shot at much higher velocities because nobody is going to aim it at something they don't want to put a hole in. Faster = less deviation from wind = more accurate, and then adding mass into the equation we get a shot that can really go where you point it over 100 or so feet.

 

If you want to increase the accuracy of airsoft BB's you need to focus on factors that don't negate the whole point of airsoft - it's intended to be a toy gun that can't hurt people even if used improperly. We all know we can build a "toy gun" that can draw blood, but operating within the constraints of not drawing blood there is a lot of room for improvement in accuracy.

 

It does occur to me that a ~.40g round shaped kind of like two .20g BBs wlded together might actually work. Rifling was a revolution with lead shot, but it may not be the answer for plastic shot. Hop-up was a revolution with plastic round BB's and required a significant step away from "traditional" thinking based on gunpowder firearms. I'm sure there is a lot of room for refining the hop-up concept.

 

A grooved barrel or perhaps rifling on the projectile a la shotgun slugs might have useful application. But just like hop-up, major increases in airsoft accuracy might very well require a major step way from real steel technology and demand thinking about the problem as fundamentally different than lead and gunpowder technologies. Because it is.

Edited by 40oz

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They already made em.

http://www.rap4.com/store/paintball/rap4-airfin-bag-of-10000

RAP4 uses a biodegradable shell, to keep anything from airsoft pellets in, their airfins, or paintballs (with the conversion kit)

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I wonder, if instead of using hop up, you could use a system like an LRB of the older Classic era weaponry. It was really just a slight incline to the barrel that provided a much more consistent output than hop up on AEGs. The only downside was A.) They were expensive, and B.) BB-weight specific.

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LRBs had more of a banana-like shape which wouldn't be possible with a longer projectile. And their purpose was still to create spin, which wouldn't work either.

 

The lack of hop up is the main issue I see with this type of ammo, until we solve a problem for that we are still just gaining a slightly more aerodynamic BB and losing a critical part of airsoft guns.

 

 

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I was thinking putting spiral grooves on the bullet iteslf. not to put rifling in the barrel so to maintain the FPS around 500 FPS and to induce spin. and I have no idea what blade bullet is suppose to be

wether it be grooves on barrel or grooves on bullet it still requires a large amount of pressure to fire it. and as mentioned before it is way to high to shoot eachother with, might as well go out and buy rifles and rubber bullets and have a hay day

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