Ive just been looking at replys from Terry Ewert of Team Whyachi and he comments that variants of this bot have been on the Whyachi drawing board for a while. And that its first design ideas started out as HPA, then hydraulic, then steam. They even looked at some sort of disc shooter/coil gun methods which I dont know how they would of worked. Until they finally settled on a spinning-kinetic-flipper. Terry also commented that most people are aware that there is much more power density in NiMh cells than an pneumatic tank, its just getting a case of activating a quick powerful flipper with it so alternatively they developed a 2.5 thick 4140 flywheel which is 24 dia by 4 high and is supposed to spin at 1000rpm but they have been having problems with drag on the perimeter bearing.

Heres how Terry tried to explain how the flipper mechanism works. quote:

There is a land machined on the top of the ring. This land rings center is offset from the main ring center, which gives the stroke. There is a top link that pulls the flipper plate up which engages with the spinning land when firing. Once the engagement link does its job, a ramp pushes it back up to the re-cocked position if the flywheel is still spinning with enough energy. Well i hope you got that because there is still alot of us Uk and USA builders that havent a clue what he is trying to explain which might be aided by some pictures but apparently he only took that one picture on the site before the bot was shipped to the Uk for the now cancelled FRA Championships, once he gets it back we will have some more photos (yay!) and probably a better explanation.

Chris - http://www.featherweights.org/forum