This is a good one on HV:
Found on this site:
http://www.zerorc.com/wram-show-2008-report
"Speaking of the T-Rex 450, I chatted with Joe Ford at the Castle Creations booth, who flies his on 12S LiPos. That's not a typo - he uses four 3S 480 mAh batteries wired in series, for a total of 44.4 volts. Using a Castle high voltage speed controller, he draws only 2 amps at full throttle and full collective! He also hinted that controllers with switching BECs were under development, to meet the demands of high-draw digital servos".