[joetapley]

If an arrow spins too fast it will start to spiral in flight (gyro effect). Some people have reported this occuring with Elite spinwings. The spin rate of an arrow overall increases during the flight. If the spin rate goes too high (at the longer distances if at all) the arrow will start corkscrewing.

By going up in fletching size you are increasing the drag torque on the arrow. This allows for a higher spin rate without the gyro effect becoming significant.