Putting a debate to bed.

[sp00n]

if i had access to solid works (CAD package) i could simulate it

 

edit :- i am sooo far out of practice with cad packages, i dont think i could any more

[sp00n]

this should explane a lot .... but its quite big worded >>> http://en.wikipedia.org/wiki/Magnus_effect

 

however please do note in the above example, it uses a base ball ... good for basics, but not for airsofters, as our bbs are usually a lot lighter, hence the bb slowing "hop" effect

 

 

edit:- i just want to add, the FPS may slow, however the rotations/sec will still be pretty high, which is why it hops. this effect also explanes why your bb can go skywards with too much hop (increased rotation/sec, with the same FPS etc)

[Ian_Gere]

Ed it is documented - it's the science of ballistics. It's just that A. it's really complex so for some people the pull of the tv, x-box, their "friend's" most recent inanity on fb, in fact anything that requires less concentration, will always trump learning something, thus people have to precede such discussions with "if you find this tedious you're a penis" and there are only so many times that such people can stand acknowledging to themselves that their intelligence really does separate them from the mass of humanity, hence bringing up complex science in connection with hobbies is rarely done, and B. for anyone who does understand ballistics in the kind of depths the details of our discussion have reached, the prospect of having to teach random forum members enough physics to take them from some unknown degree of understanding to post grad applications has got to be a bit daunting.

[ScoobySnacks]

And C, research is expensive! That's why areas that can make money (pharmaceuticals, electronics etc.) get FAR more research done than areas that aren't as lucrative.

[ScoobySnacks]

And as for the "hop up" at the end of flight, I reckon spoon has it about right. The velocity decreases, but the rate of spin doesn't (at least not as much) As this happens, (you can work it out with vectors, a fast moving BB has more "form drag" which shifts the "centre of pressure" further forward. As the BB slows this shifts the vector to a more vertical direction) the "centre of pressure" (the place on the BB where the lift can be said to act) moves closer to the "centre of gravity" (the point on the BB where the mass can be modelled as acting) and hence there is more lift vector acting in the "up" direction, hence the ball may climb somewhat.

[Ian_Gere]

Yeah, my limited understanding told me it must have something to do with the angle at which the drag affects the BB and what shape of 'wing' the vortices around the BB make. It's sort of the same as why counterintuitively a pick up truck with the tailgate up is more fuel efficient than with it down or off, b/c the vortex trapped in the back by the tailgate has a smoother profile than if the drag just sucks at the back of the cab...