Chapter 4 Incompressible Flow Over Airfoils Of the many problems now engaging attention, the following are considered of immediate importance and will be considered by the committee as rapidly as funds can be secured for the purpose. . The evolution of the more efficient wing sections of practical form, embodying suitable dimension for an economical structure, with moderate travel of the center-of-pressure and still affording a large range of angle-of- attack combined with efficient action From the first annual report of the NACA 1915Chapter 4 Incompressible Flow Over Airfoils Of the many problems now engaging attention, the following are considered of immediate importance and will be considered by the committee as rapidly as funds can be secured for the purpose…. The evolution of the more efficient wing sections of practical form, embodying suitable dimension for an economical structure, with moderate travel of the center-of-pressure and still affording a large range of angle-of- attack combined with efficient action. From the first annual report of the NACA, 1915