NACA Report No. 736

NACA Report No. 736 - Nonstationary Flow about a Wing-aileron-tab Combination Including Aerodynamic Balance was issued by the United States National Advisory Committee for Aeronautics in 1942. It analyzes the oscillating air forces on an airfoil that is equipped with various control or lift-augmenting devices.

Summary
NACA Report No. 736 presents a continuation of the flutter analysis published in NACA Report No. 496. The results of that paper have been extended to include the effect of aerodynamic balance and the effect of adding a control tab to the aileron. The aerodynamic coefficients are presented in a form usable for application to the flutter problem.

NACA Report 736 presents theoretical expressions for the forces and the moments in a uniform horizontal air stream on a plane airfoil performing small sinusoidal motions in several degrees of freedom: verticaI motion, torsional movement about an arbitrary spanwise axis, aileron movement about a hinge axis not necessarily located at the Ieading edge of the aileron, and tab movement similar to the aileron movement. The solution of this problem has direct application to the larger problem of flutter involving these various degrees of freedom and, in particular, to flutter of tails with control surfaces, including servocontrols. The development of the theory is analogous with that of Report No. 496, which treats the case of three degreea of freedom: vertical motion, torsional movement about an arbitrary spanwise axis, and an aileron movement about a hinge axis located at the aileron's leading edge.

Conclusions
The material presented in NACA Report No. 736 represents an extension of the work in NACA Report No. 496, which has been expanded to include tab functions, and the effect of aerodynamic balance. Inasmuch as this addition fits in with the general arrangement of the earlier report, reference should be made to that report, and also to NACA Report No. 685, for application to the flutter problem.