The
first DC-4 was designed in 1936 and included a triple tail. This DC-4 was eventually redesignated the DC-4E.
A new DC-4 was designed in 1939--lighter in
construction with a new high-aspect ratio wing and a conventional tail. No prototype was built; the DC-4
went straight into production.
Before the
first aircraft flew, the U.S. Army commandeered production.
The first DC-4 flew in military markings in early 1942 as the C-54
Skymaster. The DC-4 was also flown by the U.S. Navy as the
R5D. Over 1,000 were built.
Demilitarized
C-54s and R5Ds were used by commercial carriers in the early
post-war years until the next generation of airliners became
available.
The C-54 and R5D were
instrumental in the Berlin Airlift of 1948-1949. Two famous
C-54s are Gen. Douglas MacArthur's "Bataan" and President
Franklin Roosevelt's "Sacred Cow".