* Radio: PWM, (C)PPM, PCM explained https://www.youtube.com/watch?v=GbUMC8h2uhU
* TBS intro http://fpvlab.com/forums/showthread.php?265-Team-BlackSheep-system-setup-philosophies
* https://youtu.be/gRSPFYlKo58 How to build Retracts for Quadcopters/multirotors
* http://www.tjinguytech.com/charging-how-tos/parallel-charging Chargin two batteries pack
== Calculators ==
* http://www.readytoflyquads.com/
* http://www.surveilzone.com/ (free shipping)
== How-to ==
* https://youtu.be/gRSPFYlKo58 How to build Retracts for Quadcopters/multirotors
* http://www.tjinguytech.com/charging-how-tos/parallel-charging Chargin two batteries pack