Although the Japanese civil versions were nearly identical to their Douglas equivalent, the military variants, while visually similar, were substantially different. The Kinsei 51/53 engines had 1,325 hp (975 kW) and featured enlarged nacelles and large propeller spinners, while the cockpit bulkhead was moved back 40 inches (100 cm) so all four crew members forward were in one compartment, with three extra windows added behind the cockpit. The most radical changes to the original design came about due to wartime exigencies in shortages of strategic materials, that led to metal components in less critical structural areas being replaced by wood. As many as 20 transports featured wooden rudders, stabilizers, ailerons, fins, elevators and entrance doors. An all-wood variant, the L2D5, was read