I have the os 46AX. That's what it said to put on it. I already spent the $100 dollars on it, so getting another engine is out of the question right now.
A buddy of mine has a zero from another company stationed in Vietnam. He said all the packaging is identical to Phoenix model's packaging. Looks to be the same company, and his plane was a bit more tail heavy than mine.
Someday will try to find a way to make space in the fuel tank area for the battery. That should help.
Guess we get what we pay for. An ARF for $130 is cheap.
Mark