Good range for a GBB

[markedman]

Bernoulli's principle as applied to an airsoft pellet is as follows. As a spinless spherical pellet flies along its trajectory through the air (the air being the "fluid" in this case) the pressures on all sides of the pellet are equal because the air is traveling the same velocity relative to the surface of the pellet. If a spin is applied to the pellet about an axis perpendicular to the velocity vector (e.g, a backspin) the air will be rushing faster (relative to the pellet surface) on the side that is spinning away from the velocity vector and slower on the side that is spinning towards the velocity vector. Bernoulli's principle says this difference in fluid velocity implies a difference in pressures, which is a force that will cause the pellet to move in a direction perpendicular to the velocity vector.
Airsoft hop-up devices apply a backspin to the pellet so that the pressure force acts on the pellet opposite the direction that gravity is pulling it. This causes the pellet to fall less over a given distance than it would without the spin applied to it.
In airsoft guns this is often implemented as a rubber piece at the rear of the barrel that is thicker at the top of the barrel than the bottom. As the pellet moves past this piece it tends to roll, inducing a backspin. This is usually adjustable so that the effect can be tuned.

more on this can be found here
http://en.wikipedia.org/wiki/Airsoft#Airsoft
:tup:

[Bordush]

I know this is a very old thread, but I would like to add something.

If you drop two BBs from the same height at the same time, but give BB #2 forward momentum, they will both hit the ground at the same time. The BB is going in 2 directions, FORWARD and DOWN. If the BB is shot perfectly strait, then gravity is the only thing forcing it down. So if they'll hit the ground at the same time, then the faster the BB is going, the farther it will get before hitting the ground.

The hopup is the next factor. Markedman did a very good job of explaining the physics involved in this.

The question now is, which is a bigger factor. I believe the velocety is although I don't have proof to back that up. But I think it is quite obvious. The velocety is also needed in order for the backspin to even exist. The higher the FPS the more the BB will spin, although a heavier BB would be needed so that it wont spin too much.

Real-Steal guns don't have hop-up (of course) but if you found 2 rounds that are the same wieght and aero-dynamics, but one fires at a higher velocety, which do you think would go further? (I guess .308 and 30-06 would be a good example?)

Mark

My Stock Hi-Capa outranges stock AEGs on propane easy....more accurate too.