Low-Speed Experimental Study of the Directional Characteristics of a Sharp-Nosed Fuselage Though a Large Angle-of-Attack Range at Zero Angle of Sideslip

摘要

An investigation was made in the Langley stability tunnel to determine the directional characteristics of a sharp-nosed fuselage model through a large angle-of-attack range at zero angle of sideslip. The results showed that the fuselage experienced a large increase in yawing moment as the angle of attack increased, owing to asymmetrical disposition of the pair of trailing vortices emanating from the nose. A ring or other roughness used on the nose caused (mainly by altering the vortex disposition) a large decrease in the yawing moment obtained at high angles of attack; in fact, for some angles of attack the yawing moment was of a sense opposite to that obtained with a plain fuselage. Although the reason that the ring altered the vortex disposition has not been established, the use of a ring may be convenient for studying the reversal of vortex disposition, and hence of load, which has been found to be self-induced and to occur aperiodically for some fuselages in other investigations.