Manuscripts/Mixed Material Article by Alexander Graham Bell, October 11, 1910
This conclusion, the Wright brothers and Santos Dumont, have demonstrated to be incorrect; but Prof. Newcomb's objections undoubtedly have great force; and reveal the cause of the failures of attempts to construct large-sized flying-machines upon the basis of smaller models that actually flew.
Prof. Newcomb shows that where two aerial vehicles are made exactly alike only differing in the scale of their dimensions, the ratio of weight to supporting surface is greater in the larger one than in the smaller, — the weight increasing as the cube of the dimensions, whereas the supporting surfaces only increase as the squares.
From this conclusion it is obvious that if we make our structure large enough, it will be too heavy to fly even by itself — far less be the means of supporting an additional load like a man, and engine for motive power. This conclusion is undoubtedly correct in the case of structures that are “exactly alike excepting in their dimensions”, but it is not true as a general proposition.
A small bird could not sustain a heavy load in the air; and while it is true that a similar bird of double the dimensions would be able to carry a less proportionate weight because it is itself heavier in proportion to its wing surface than the smaller bird eight times as heavy in fact, with only four times the wing surface — still it is conceivable that a flock of small birds could sustain a heavy load divided