Dave,

Yes is the short answer, every plane I have needs negative push to hold level while inverted, including my C-ARF 2M pattern plane. interestingly enough someone told me this was wrong, they said a good plane trimmed out properly will go inverted without any push. Quite frankly I never knew if that was right or wrong, seemed a fair enough argument to make but nothing I've flown will do that.

While at SEFF this year I had the chance to talk to QuiQue Somenzini, I asked him if this was true and he said absolutely not, He said sure, you can likely trim a plane out so that it flies the same right-side up as well as inverted but you'll end up with a poor flying (and tracking) plane. he said every plane needs a little push when inverted to hold its line and you should spend the time trimming the plane to track properly...

Jack