The F4U Corsair was one of the most successful fighters of WWII. It achieved a claimed 11.3 to 1 'kill ratio' in the Pacific. It was fast, but had some handling problems, and early versions tended to 'bounce' upon landing because of their stiff undercarriage. Therefore it was at first restricted to land-based marine units, and equipped all USMC fighter units in the Pacific in the second half of 1943. After some modifications, it was used also for shipboard operations, but continued to require careful handling. The vast majority of F4U sorties (54,470 out of 64,051) were flown from land bases. The F4U had an inverted gull wing, a streamlined fuselage of circular cross-section and a big propeller. The cockpit was set well back, and the restricted view was a serious problem.