Jet fighter aircraft lateral directional stability at high angles of attack.

The discussion of the structural methods for obtaining lateral stability discloses the remarkable influence of the constant fuselage and wing proportions to the yawing moments. For the effectiveness of modifications in vertical tail surfaces and tail length, these quotas - little observed heretofore, in this connection - are decisive. This also applies to the amount of dihedral of the wing with regard to the roll stability of the complete wing already existing without angle of the dihedral.

A test and analysis method is presented for determining airplane lateral stability characteristics, including aerodynamic derivatives, from flight tests of scale models. The method of analysis utilizes the rotating time-vector concept and also a quasi-static approach. Data are presented at transonic speeds for three swept-wing rocket-propelled models differing only in vertical position and dihedral of the wing. The method proved to be adequate for delineating the major effects of the geometric variations on the aerodynamic lateral stability derivatives. The effects of Reynolds number on the linearity of the static stability data for an unswept wing configuration are illustrated.