Avia pursuit airplane B.H. 21
An NACA Aircraft Circular from 1926 issued by the National Advisory Committee for Aeronautics, documenting the Avia B.H.21 pursuit airplane through technical photographs and drawings for engineers and aviation researchers. The two plates show the fighter from several angles: a three-quarter photograph of the biplane with its Hispano-Suiza engine, and orthographic line drawings of front, side, plan and rear views with labelled dimensions. A designer could take the crisp, measured geometry of the orthographic views as a clean reference for stripped-down mechanical line work.
