DFS Dive-control Brakes for Gliders and Airplanes ; And, Analytical Study of the Drag of the DFS Dive-control Brake

These two reports are surveys on the progress and present state of development of dive-control flaps for gliders and airplanes. The second article describes how on the basis of wind tunnel and free-flight tests, the drag increase on brake flaps of the type DFS, can be predicted. Pressure records confirm a two-dimensional load distribution along the brake-flap surface Aerodynamically, the location of the brake flaps along the span is of importance for reasons of avoidance of vibration and oscillation phenomena on control and tail surfaces; statically, because of the magnitude of the frontal drag in diving with respect to the bending moments, which may become decisive for the dimensions of the wing attachment and for the wing covering.