Summary of Low Speed Airfoil Data”
Volume 3
Professor Michael Selig and his students couldn't complete the book on series three before series four was well along. They decided to combine the two series in a single volume of 444 pages. This issue contains much that is new and interesting. The wind tunnel was improved significantly and pitching moment measurement was added to its capability. 37 airfoils were tested. Many had multiple tests with flaps and or turbulation of various configurations. All now have the tested pitching moment data included.
As in previous volumes, the airfoils tested are separated into several groups. This is the first volume of this series, which includes actual wind tunnel measurement of pitching moment.
Listed first are airfoils for use in R/C soaring competition. While extensive wind-tunnel data already exists for many of these airfoils, several were re-tested with various trailing-edge flap settings as suggested by R/C soaring enthusiasts. In particular, large flap settings of 15° to 25° were tested to give insight into possible performance improvements during launch, and smaller flap settings of 2.5° are representative of typical control deflections during thermal soaring. Supplementing this data are leading-edge flap settings of -3° and 2.5° tested on the popular SD7037. Also, as variations of the popular SD7037, three new airfoils, the SA7035, SA7036, and SA7038, were designed and tested.
The second group of airfoils listed is those for use on powered R/C aircraft. With a majority of the attention from airfoil designers focused on the design of new R/C soaring airfoils, a large disparity in performance has resulted between sailplane and powered airfoils. With this volume, the UIUC LSAT's team has attempted to lay the foundation for reducing this disparity. To be more specific, several airfoils used on popular powered R/C aircraft were tested to provide a benchmark against which new designs can be compared. Serving as an indicator of the possible performance improvements, three new airfoils, the 58036, 58037, and 58052, were designed and tested.
Airfoils for use on small wind turbines comprise the third group of airfoils tested. Among these are four new airfoils (SG6040 - SG6043) specifically designed for variable-speed wind-turbines. The reader will note that several of the airfoils listed here were designed specifically for use on aircraft (A18, SD7032, and SD7062). These airfoils, together with three others grouped under the "Sailplane" and "Powered Aircraft" headings (Clark-Y, 57012, and SD7037), were tested with leading-edge roughness to establish their potential for use on small wind turbines.
The last group is comprised of any airfoils that we found difficult to categorize. It should be stressed that while an attempt was made to classify every airfoil, the application of each airfoil is by no means limited to their respective groups. This is evident in Chapter four of the book where several airfoils are discussed in more than one context.
Finally, this volume contains a rather extensive study of the effect of boundary-layer trips on airfoil performance. Two candidate airfoils were selected which are representative of a majority of the airfoils used on R/C model aircraft. These were the SD7037 and the E374. Each was tested with various trip configurations (single, multiple), geometries (2-D, 3-D), locations, and heights.
Airfoil test results included in Volume 3.
