Cyclic rings on Radios... why?

[DsWright]

what exactly do they do? Is it something i'll be able to use if im a plank flyer as well?

What advantages are there to using them?

[ClayK]

My understanding is so that you don't go to the extreme corners and bind the servo's while rolling the cyclic in a circular motion (imagine whipping eggs or mixing or something similar). Piro flips are where I would see this coming in handy. Something I don't see myself doing for quite a while....