Robinson, Robert C.
Tests were conducted to find the effects of compressibility on the longitudinal stability and control of a 1/7-scale semispan model of the Northrop YB-49 airplane. Lift, drag, pitching moment, and elevon hinge moments were measured and are presented in graphical form. The results show that, due to a loss of lift on the outboard portion of the wing, the longitudinal static stability decreased rapidly as the Mach number increased above 0.725 and for Mach numbers above 0.735 the model experienced a climbing moment at positive lift coefficients. Also, longitudinal-control effectiveness began to decrease at a Mach number of about 0.725.
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