I don't know whether this is in the correct forums. I have a kind of a "out of curiosity" question.

What influence does the total weight of the plane have on it's flight ability/chararistics?

In other words, lets say you have exactly the same plane with the same engine size...the one is heavier than the other - lets say 500grams or so over the recommended weight and the other is 500grams or so below the recommended weight. Would the lighter one fly better, but will it tend not to handle wind as well < just as an example.

This is just something I was wondering about today. If there is another thread explaining this which I missed then could someone post a link. Thank you