โ Scribed by National Advisory Committee for Aeronautics
No coin nor oath required. For personal study only.
This report gives the results of pressure-distribution tests made to study the effects on lateral stability of changing the span-load distribution on a rectangular monoplane wing model of fairly thick section. Three methods of changing the distribution were employed: variation in profile along the span to a thin symmetrical section at the tip, twist from +5 ยฐ to -15 ยฐ at the tip, and sweepback from +20 ยฐ to --20 ยฐ . The tests were conducted at the Langley Memorial Aeronautical Laboratory in the 5-foot closed-throat atmospheric wind tunnel.
The rolling moment due to roll at a rate of rotation equivalent to that resulting from the maximum rolling disturbances encountered in normal flight is used as the principal basis of comparison. Normal-force curves are given for the purpose of estimating the general effectiveness of each wing arrangement.
The investigation shows the following outstanding results: I. Change in profile along the span from the N. A. C. A. 84 at the root to the N. A. C. A.-M2 at the tip considerably reduces lateral instability, but also reduces the general effectiveness of the wing.
3-Transition from sweepforward to sweepback gradually reduces the useful angle-of-attack range, but has no clearly defined effect on maximum later instability.
๐ SIMILAR VOLUMES
In this report prepared for publication by the National Advisory Committee for Aeronautics, in June, 1927, are outlined the three current methods of comparing dynamically similar motions, more especially of fluids, initiated respectively by Newton, Stokes (or Helmholtz), and Rayleigh. These three me
## PUBLICATIONS RECEIVED. 399 Report No. 391. The Aerodynamic Characteristics of Eight Very Thick Airfoils from Tests in the Variable Density Wind Tunnel, by Eastman N. Jacobs, I4 pages, illustrations, quarto. Washington, Government Printing Office, I93I, price ten cents. A group of eight very thi