A few months ago I bought a few indoor helis. They help greatly keeping my eye-hand coordination sharp in a small 3D space. It translates well for playing BZE, especially for BoPs where decisions have to be made quickly. However, after a short time, the stock heli
(center) became no challenge, so I stripped one of them down, removed the canopy, landing gear, boom supports and associated stabilizers. . . reducing the weight by approximately 15%
(ones on shot glasses). After a couple weeks, that one too became less and less of a challenge. Finally, in an attempt for mindless speed and insect-like response, without any kind of 'braking', I removed the boom and rear motor and reset the battery position, throwing the CG ridiculously forward and removing somewhere around 30% of the original mass.
I've met my match, but does it ever keep the reflexes razor sharp!
