The Manufacture of Metal Airscrew Blades

IN the construction of their airscrews the Hispano Suiza Company use principally aluminium alloys—duralumin, alfcrium, avional—with a mean density of 2·8, and with mechanical properties equal to those of a half‐hard steel. They have been considering for some time the manufacture of blades of magnesium alloy, the mean density of which is 1·8, thereby offering considerable advantage over the aluminium alloys as regards weight, but, in this article, only aluminium alloy blades are dealt with.