Spin is generated by drag on the fletching, basic physics.

Feathers have more drag (and therefore more spin if offset angled) than vanes fletched the same way.

Since the spin is generated by drag on the fletching, explain to me how you can spin faster with less drag?

The kicker on the rear of the QS vane causes quite a bit of drag since it is almost perpendicular to the vane itself. That kicker, and the drag it causes, is the key to the high spin rate of the QS. That, and they "say" that the micro-grooves on the opposite side of the vane reduce air pressure on that side of the vane as it is flying which also aids in spin. I'd like to tinker with a QS vane that doesn't have the micro grooves on the other side to compare to the present version that does- just to see if that claim is true.

I'm impressed with these vanes so far, but I wish the durability was better. Flex-fletch sets the bar pretty high..... I've been using QS's for indoor target and will be using them for outdoor field this summer.