I personally have the Flysky radio and I love it. I also have most of the Castle ESCs and products. However, I have noticed that the Flysky radio has a hard time arming the Castle esc's. The esc can detect the number of lipo cells but it does not arm, if it does arm it takes a long while. Using other esc such as Novak and Tekin with the Flysky also has a hard time arming. I believe the problem is with the flysky radio having a very narrow neutral position and that can be problematic for esc's to locate the neutral position and thus has a hard time arming.

Solution: get a spectrum dx4c radio, cheap and very easy to use. Futaba, sanwa are also great radios.