Vought XF4U-3B
High-altitude XF4U-3B
To develop a high-speed, high-altitude F4U, Vought took three prototypes and gave them R-2800-14W engines. This enabled them to reach speeds of 772 km/h and altitudes of 12,192 m. However, the variant did not offer an appreciable increase in performance over the F4U-4 and was therefore not adopted.