The DC-6 was to the DC-4 what the DC-3 was to the DC-2.
Four Pratt & Whitney R-2800 engines gave the DC-6 more than 8,400 hp and improved its speed to 350 mph from the DC-4
’s 240 mph. Payload was increased from 11,000 to 14,000 pounds and range extended from 1,750 to 2,600 miles. Cabin pressure was maintained at 5,000 feet while flying at 20,000.