Supercharging Makes the Difference

Coming later this year from the Steve Ginter Naval Fighter series - my monograph on the Bell XFL-1 Airabonita. This little known pre-WWII Navy fighter prototype was based on the more successful Allison V-1710 powered P-39. Contemporaries were the XF5F and XF4U. It was one of several examples of U.S. Navy involvement in liquid-cooled engine projects after 1929. The chart shows the difference in airspeed at altitude due to supercharging. The XFL-1 was handicapped by not only by having less installed horsepower than its competitors, but also only having a single-stage supercharger. At altitudes below18,000 feet, it was significantly faster than the F4F-3, which had an engine of about the same horsepower, but then lost the advantage because the Wildcat's engine had a two-stage supercharger.