As a TK barrel user, I think that TNL has the right answer, it doesn't spin the BB sideways, it just makes a spinning cushion of air inside the barrel to insure the BB doesn't hit barrel's wall when popping out.

God, this conversation again.

Spin works because if the magnus effect. When it spins sideways (on a sphere) the air wants to hold on to the surface. It is the angular velocity cross the velocity, which gives the bb an upward force. Having sideways spin on a bb (stupid) will curve your bb sideways. Having hopup and sideways spin will curve your bb diagonally.

As said before by a few people, the tk barrel creates a "vortex" of air around the edges of the barrel. This causes the bb to want to be in the center of the barrel more because it is pushed towards the center because that is the location of lowest energy. (potential)

As to the bb "spiraling", I don't see how this would be possible. That's like throwing a baseball with so much spin it comes back to you. With a frisbee, maybe.. with a bb ball or a bullet, no. If you're saying that the bb is spinning on two axes, then yes, but I don't know if this is possible. (hopup with rifling is still spin on one axis, but one that is diagonal) That means the spin of the bb is changing directions, and this would only work for something that looks like a gyroscope/gimble thing.

TK problem for me
 

Hello guys

I just installed a TK barrel in my L96. I did some test firring this weekend. I was not expecting this problem but the bbs started spiralling counter clockwise in the same direction as the barrel.

From what I was understanding of the cousin of air it should not of affected the path of the bb. Did I do something wrong in the install? Do I need to do something special with the hopup?

Thanks for any help

what is the fps of the bb..... anything over 350 and your loosing accuracy

It sounds like your hopup might be screwy. I'm assuming spiraling means curving? I still can't imagine a knuckleball bb? If you're hopup is off and is hitting off center, it will cause diagonal spin and will make the bb curve sideways.

I'm assuming he's shooting WAY too hot for a TK Twist barrel.

no, spiraling as in spiraling, as in it spirals....

like a silly straw

I guess I don't really have any intuition of what would happen in a twist barrel if the air were moving too quickly, but from a physical standpoint, it is kind of hard to get a sphere to "spiral" through the air. I'm no longer doubting that it is possible, but trying to grasp how.... Like I said earlier, one of the ways to make it spiral would be to somehow give the bb a changing spin on the bb, or something like a plane using its ailerons to give it spin and its rudder to give it a "spiral". It is possible that the "cushion" of air follows the bb forward, and if the air is spiraling, it might have a weird effect, but I'd imagine the air stops much earlier than the bb.

because the hopup gives it a backspin, and then if the FPS is too high the air vortex can give it a spin on an axis parralel to the flightpath, meaning that the backspin will rotate to the side then the bottom then the other side then back up as the BB spins on 2 axis

or something

this is all being pulled out of my logic centers' ass

The problem with variable spin, is that when you spin, lets say along the x and y axis, it doesn't spin along 2 axes, but spins along the x=y axis, so it will curve diagonally. Variable spin on a solid sphere is very complicated, and I'm trying to figure out a way how, and haven't yet. If you think about a bowling ball, the spin on the ball will automatically stablize until it is no longer a variable spin.

420 fps with 0.20g

I was testing with 0.28 g

I will check it out tomorrow. Good starting point.

According to ILLusion the TK twist works ONLY ON 1 JOULE or LESS with performance going down as you get higher speeds and the performance being "acceptable" (he didn't quantify it as only preliminary qualitative remarks were made) at 1.14 Joules (350 on .20's).

So by using .28's you're still shooting at 1.64 Joules. It doesn't matter what weight you're using 1.64 J is still 1.64 J and is independent of weight.

So basically it's not a very good barrel.

If you were going to put in a modified FAMAS that shoot around 250. Would you get good performance out of it.

It's a good barrel if you're shooting at one joule or less.