Turnigy/Hobbywing ESC's w. custom firmware for Xaircraft
The "fast PWM" ESC firmware for generic Atmel based ESC's http://www.rcgroups.com/forums/showthread.php?t=1513678
should now support 200-1200 ms UltraPWM as used by Xaircraft.
This means affordable ESC's in all sizes, the end of the annoying 8kHz motor whine and hopefully getting rid of the disturbing clicking noises due to bad timing.
Still in beta, someone should give this a try and post feedback in the ESC DIY flashing thread.
Post with relevant details for UltraPWM: http://www.rcgroups.com/forums/showp...5&postcount=41
Preliminary tests suggests that the reflashed ESC's also draws less current, meaner longer flight times, this is yet to be confirmed.