As a class, the large and heavy four-engined tail-wheeled bombers such as the Stirling, Handley Page Halifax, Avro Lancaster and Boeing B-17 Flying Fortress could be a handful on takeoff and landing, more so for relatively young and inexperienced new pilots who formed the vast majority of the expanding Commonwealth and American air forces. Later heavy bomber designs such as the Consolidated B-24 Liberator and Boeing B-29 Superfortress used a nose-wheel (tricycle) configuration as did most successful four engined commercial aircraft in the post-war years. Tricycle geared aircraft are typically easier to control on takeoff, landing and during taxiing, and also make for easier cargo loading and servicing as the cabin, engines and other systems are closer to the ground. The long undercarriage of the Stirling was a result of a request by the RAF who sought to increase the wing incidence.