Low-speed wind-tunnel tests of a large-scale inflatable structure paraglider

Aerodynamic characteristics of inflatable structure paraglider tested in wind tunne

The Royal Path of Life or Aims and Aids to Success and Happiness

This book was written by Thomas Louis Haines and Levi W. Yaggy. The Royal Path of Life follows the vast subjects of success and happiness. The authors state that they hope the book, “...shall be a counselor to those who have become indifferent to life’s purposes; and comfort to those who have long traveled on this Roylar Path” and that it, “...shall serve to awaken the slumbering genius within the youth, stimulate and impel them to noble thoughts and actions, and lead them on to honor success and happiness.” The books within the Mother, Home, and Heaven Collection were given in honor of Josephine Long Wishart by her daughter Josephine Wishart Hayford, who graduated from the College of Wooster in 1937.https://openworks.wooster.edu/motherhomeheaven/1023/thumbnail.jp

WIND-TUNNEL TESTS OF A SERIES OF 18-FOOT-DIAMETER PARACHUTES WITH EXTENDABLE FLAPS

Parachutes with extendable flap

A Wind-Tunnel Investigation of the Stall-Flutter Characteristics of a Supersonic-Type Propeller at Positive and Negative Thrust

An investigation has been made utilizing a three-blade, 10-foot- diameter, supersonic-ty-pe propeller to determine propeller flutter characteristics. The particular flutter characteristics of interest were (1) the effect of stall flutter on a propeller operating in positive and negative thrust, (2) the effect of stall flutter on a propeller operating with the thrust axis inclined, and (3) the variation of vibratory blade shear stresses as the stall flutter boundary is penetrated and exceeded. Thrust and power measurements were made for all test conditions. Wake and inflow surveys were made when appropriate, to define the thrust and torque distributions and the magnitude of the inflow velocity. Stress measurements were made simultaneously to obtain the propeller flutter and bending response. It was found when operating both in the positive and negative thrust regions that, for most cases after the onset of flutter, the magnitude of the flutter stresses at first increased rapidly with section blade angle P, after which further increases in 0 resulted in only a moderate increase or a reduction in stress. Thrust-axis inclination up to the limit of the tests (angle of attack of 15 deg and dynamic pressure of 40 psf) appeared to have no effect on stall flutter. The stall flutter stresses were found to be directly associated with the section thrust characteristics of the blades. The onset of flutter was found to occur simultaneously with the divergence of the section thrust variation with blade angle from linearity for stations outboard of the blade 0.8-radius station. The maximum flutter stresses appeared to be a function of the maximum section thrust obtained at or in the vicinity of the blade 0.8-radius station. In an attempt to correlate two-dimensional airfoil data with three-dimensional data to predict the stall angle of attack (divergence of the section thrust) of the blade sections, it was found that no consistent correlation could be obtained. Also, a knowledge of the inflow conditions appeared to be insufficient to account for differences in airfoil characteristics between the two-dimensional and the three-dimensional cases

An Analysis of Once-per-revolution Oscillating Aerodynamic Thrust Loads on Single-Rotation Propellers on Tractor Airplanes at Zero Yaw

A simplified procedure is shown for calculating the once-per-revolution oscillating aerodynamic thrust loads on propellers of tractor airplanes at zero yaw. The only flow field information required for the application of the procedure is a knowledge of the upflow angles at the horizontal center line of the propeller disk. Methods are presented whereby these angles may be computed without recourse to experimental survey of the flow field. The loads computed by the simplified procedure are compared with those computed by a more rigorous method and the procedure is applied to several airplane configurations which are believed typical of current designs. The results are generally satisfactory