with cargo doors forward and aft of the wing on the left side, with a cargo floor; the DC-6B for passenger work, with passenger doors only and a lighter floor; and the DC-6C convertible, with the two cargo doors and removable passenger seats.

The DC-6B, originally powered by Double Wasp engines with Hamilton Standard 43E60 constant-speed reversing propellers, was regarded as the ultimate piston-engine airliner from the standpoint of ruggedness, reliability, economical operation,