RE: What size speed control?
It should have been big enough, but..... el cheapo ESCs are often not up to their rating.
Here is a posting from RC Groups:
I like cheap ESCs too, but I also like some minimum level of quality. If you go for the lowest price ESCs, you should derate them to maybe 70-80% of their stated capacity and never run them above that.
For my money, the Hobbywing Pentium ESCs (and their rebranded cousins, such as the Turnigy Plush/Sentry, EMAX, Don's RC, and others) are the best value. I've had over a dozen over the last few years, from 6A to 25A, and only one ESC has ever failed on me (10A, in flight, for unknown reasons). I also have the program card, that works across all of the compatible ESCs and makes it a no-brainer to set the various options.