Hollow Steel Airscrew‐Blade Production Available to Purchase

HOLLOW steel airscrew‐blades which, it is claimed, are stronger, weigh no more, and are less susceptible to impact and abrasion than forged aluminium blades of the same size are being manufactured in quantity from seamless steel tubing by the American Propeller Corporation, a subsidiary of the Aviation Corporation. The conception of using tubing for blade making is logical, but the difficulties of putting it into practice were great and required the development of many new methods and production tools. For the following description and accompanying illustrations, the author is indebted to the Propeller Corporation and to supplemental information contained in an article in Steel written by A. H. Allen, Detroit editor of that journal.