Strength calculations on airplanes NACA Technical Memorandums per Baumann, A org National Advisory Committee for Aeronautics 1925-12-01 eng Every strength calculation, including those on airplanes, must be preceded by a determination of the forces to be taken into account. In the following discussion, it will be assumed that the magnitudes of these forces are known and that it is only a question of how, on the basis of these known forces, to meet the prescribed conditions on the one hand and the practical requirements on the other. NACA TRAIL UNTGD public