In action to my comments on the product made use of for the arms on the Holybro Kopis 2 SE racing miniquad, this video clarifies a bit a lot more about exactly how composites such as carbon fiber get their strength as well as why a foam/carbon layup might be as stiff as solid carbon yet is no place close to as strong.

Keep tuned for the continuous testing of the Kopis 2 SE, the arms may not be strong carbon yet they may well be "strong sufficient".