What kind of engine was it? If you hang around the field long enough, you will find that "clubs" will have opinions on what engines are reliable at that location. I know it sounds weird, but once someone finds something that works, it seems to work for everyone at the field.

As for the radio, ask someone to put a volt meeter on your batteries. There are several things that can cause a "hit". Again it may sound weird, but some fields may tell you that "channel XX just doesn't work here". Hope this helps.