How long did it take an R7V-1 to convert from a passenger plane to a freighter?

In August 1950 the US Navy ordered eleven convertible passenger-and-cargo aircraft based on the L-1049B Super Constellation, the stretched version of the Constellation it had already ordered as the WV-2 early-warning platform. Initially designated R7O, they were delivered before the WV-2 because they were simpler to build. The R7O, later renamed R7V-1, first flew in 1952.

Its great virtue was flexibility. The R7V-1 could be quickly converted from a passenger transport carrying 97 to 107 people into a cargo aircraft in two hours. The Navy reduced the number of available seats to make room for life rafts on flights over water, and the aircraft could also carry 73 stretchers on medical evacuation flights.

The R7V-1s served over the Atlantic and Pacific in squadrons VR-1, the Navy's oldest transport squadron, VR-7, and VR-8, and two modified aircraft were used on resupply missions to Antarctica. The family of military transports derived from the Constellation had begun with the Air Force's C-121A, some of which were converted into VIP transports under the designation VC-121A; the last C-121A were retired in 1968. The Constellation, with its triple tail and four Wright R-3350 radial engines, was for decades one of the great long-range transports of the US armed forces. According to Super Constellation production records, the Navy received a total of 50 R7V-1, plus two R7V-2 of the L-1249A series.