The early P-47s were 'razorback' canopy configuration with a tall fuselage spine behind the pilot, but resulted in poor visibility to the rear. The British then devised an all-round vision 'bubble canopy' for the Hawker Typhoon. The USAAF quickly adapted it to American fighters, including the P-51 and the Thunderbolt. The first P-47 with a bubble canopy was a modified P-47D-5 completed in the summer of 1943.