How One Engineer’s “Stupid” Propeller Trick Made the P-47 a 470 MPH Monster

Early in WWII, German pilots mocked the Republic P-47 Thunderbolt as a “flying milk bottle”—deadly in a dive but sluggish in climbs. When the U.S. Army Air Forces demanded better performance in 1943, the Hamilton Standard Propeller Company’s engineering teams developed revolutionary 13-foot “paddle-blade” propellers that could finally harness the full power of the P-47’s massive R-2800 engine.

The result was shocking: climb rates jumped 400 feet per minute and top speeds reached 470 mph, transforming the ridiculed heavyweight into one of the most feared fighters by the Axis powers over Europe by D-Day 1944. 

                                 Frank W. Caldwell

The Engineer who developed the new propeller design was Frank Caldwell (at left), a long-time employee of Hamilton Standard Propeller Co. in Connecticut.  The massive Pratt & Whitney engine powering the P-47 was the P&W Double Wasp R-2800. Caldwell’s life was exceptional, having won many awards, including the highly coveted Collier Trophy and also a Presidential citation during  WWII.  He is also widely known as the inventor of the CONSTANT SPEED PROPELLER.

Disclaimer: This video is a dramatized retelling of World War II stories, created for educational reflection and entertainment purposes. Elements of the narrative have been artistically interpreted, and creative tools, including AI, were used to enhance the storytelling experience.  The video below is 39 minutes and 59 seconds long.  The best viewing experience is when the video is opened to full width and seen right here in the FASF page.