The Forged Propeller. ID: 7458 | This file appears in: SIFCO Industries, Inc. During WWII the United States attempted to launch torpedoes from airplanes only to find the propellers needed to power the missiles once they reached the water were not strong enough to withstand the force of the launch. SIFCO came to the aid of the United States with a forged, four-blade propeller with the ability to survive the impact and went on to produce every aircraft-launched torpedo propeller used by the United States throughout the duration of the war. | Source: SIFCO Industries, Inc. Download Original File SourceSIFCO Industries, Inc. "The Forged Propeller. " appears in: SIFCO Industries, Inc.