Model Variants (Including Prototypes)
DC-4 - Base Series Designation
DC-4E - Pressurized Model to succeed the DC-3; increased range; fitted with 4 x Pratt & Whitney R-2000-2SD1-G Twin Wasp engines; later changed to unpressurized type for technical reasons.
C-54 "Skymaster" - United States Army Base Series Designation; 26 passenger type; R-2000-7 radial engines; 26 total examples.
C-54A - Fully militarized US Army type; R-2000-7 engines; 50 passenger seating.
C-54B - US Army version; implemented wing tanks.
C-54D - US Army version; R-2000-11 radials.
C-54E - US Army version; redesigned fuel tanks; dual-role passenger/cargo handler.
C-54G - US Army version; dedicated troop carrier.
R5D - United States Navy Base Series Designation.
R5D-1 - Fully militarized USN type; R-2000-7 engines; 50 passenger seating.
R5D-2 - USN version; implemented wing tanks.
R5D-3 - USN version; R-2000-11 radials.
R5D-4 - USN version; redesigned fuel tanks; dual-role passenger/cargo handler.
R5D-5 - USN version; dedicated troop carrier.