
Until World War Two, aviation technology had lacked sufficient advancement to permit the carriage by aircraft of heavy, bulk cargo in the way desired by the armed forces — that is, until Gen Henry ‘Hap’ Arnold of the US Army Air Forces (AAF) issued a request to manufacturers for a dedicated cargo/troop transport. Of course, aircraft such as the Douglas C-47 and Curtiss C-46 would meet battlefield needs, but they were originally conceived as civil passenger types, so bulk cargoes had to be awkwardly side-loaded into the fuselage.