Errata and Addenda to "Application of Oscillatory Aerodynamic Theory to Estimation of Dynamic Stability Derivatives"

Abstract

T pitching moment coefficients in Ref. 1 are referred to an axis through the wing apex with the pitch axis through the quarter-chord point of the mean aerodynamic chord (MAC). It was the authors' intention to present the coefficients using the same reference and pitch axes at the quarterchord point of the MAC. The example wing had an aspect ratio of 8.0, a taper ratio of 0.25, a quarter-chord sweep of 30 deg., and was flying at a Mach number of 0.8. Using a new lattice idealization of the wing (since the original idealization was not recorded) defined by 5 equal chordwise divisions and 15 variable spanwise (narrower toward the tip) divisions, the new lift and corrected moment coefficients for the quarterchord MAC reference axis and pitch axis are presented in Table 1 for the nine values of reduced frequency previously considered. The calculations were based on the doublet-lattice method (DLM) of Ref. 2 as integrated into NASTRAN® and were carried out using MSC/NASTRAN; the original calculations were based on the DLM of Ref. 4 which was later developed into Ref. 5. Slight differences in the lift coefficients between the present and earlier solutions can be attributed to a different lattice idealization. If we extend Ref. 1 to permit different reference chords for reduced frequency (k = ub/V) and pitching moment coefficient