Don't know other than they were the MFG.-company.I'm leaning toward,better too heavy on the nose rather than heavy on the tail.Put a lot of work in mine and don't really want to crash it though.The second one I'm working on now,I really beefed up.Some of the other threads said the nose was prone to breaking off,and some broke back by the trailing edge of the wing.
I'm happy that I think I have taken measures to stop those problems on the second plane.Now I'm getting ready to start on the wing of the second one.Got several ideas but haven't decided for sure yet.Wish I knew more about useing fiber glass,but rulled that out because that can be a real can of worms if you don't know what you are doing. BIGMIG