The first Constitution, BuNo 85163, was built in the summer of 1946 at the Lockheed plant in Burbank, California.
Due to the aircraft's large size—the tail towered 50 feet (15 m)—Lockheed had to build a special hangar for final assembly.
The hangar, Lockheed-California's Building 309, measured 408 ft (124 m) long, 302 ft (92 m) wide, and the equivalent of six stories tall.
The footprint of the hangar covered 4 acres (16,000 m²).
It cost $1,250,000.

The R6O made its first flight on 9 November 1946, powered by interim 3,000 hp R-4360-18 radials.
Joe Towle and Tony LeVier flew the aircraft on a leisurely course to Muroc Air Force Base.
Once there, the aircraft underwent a carefully documented test program.
At this time, electronic data recording technology was not well developed, so instrument readings were recorded by a movie camera pointed at the instrument panel.
Additional movie cameras were carried to record test results.

The first Constitution made a nonstop flight from NAS Moffett Field, California to NAS Patuxent River, Maryland on 25 July 1948, a distance of 2,460 mi (3,960 km).
The pilot for the flight was Commander William Collins, USN and the copilots were Lieutenant Commander James W. Robinson, USN and Roy Wimmer, Lockheed engineering test pilot.
Four days later, the ship was formally christened by Mrs. John L. Sullivan, wife of the Secretary of the Navy, at Washington National Airport.

The first test flights revealed that the aircraft was underpowered so the engines were changed for 3,500 hp (with water injection) R-4360-22-W engines.
The R6O also tested assisted takeoffs with six rockets mounted on the wings near the fuselage.
At full gross weight, the rockets shortened the takeoff run by 24%.

Ship No.
1 was delivered to Navy Transport Squadron 44 (VR-44), based at Naval Air Station Alameda, on 2 February 1949.
Both it and its sister ship, Ship No.
2 (which followed six months later), flew the route between California and Hawaii, approximately 2,390 mi (3,850 km).
The first Constitution, BuNo 85163, was built in the summer of 1946 at the Lockheed plant in Burbank, California. Due to the aircraft's large size—the tail towered 50 feet (15 m)—Lockheed had to build a special hangar for final assembly. The hangar, Lockheed-California's Building 309, measured 408 ft (124 m) long, 302 ft (92 m) wide, and the equivalent of six stories tall. The footprint of the hangar covered 4 acres (16,000 m²). It cost $1,250,000.
The R6O made its first flight on 9 November 1946, powered by interim 3,000 hp R-4360-18 radials. Joe Towle and Tony LeVier flew the aircraft on a leisurely course to Muroc Air Force Base. Once there, the aircraft underwent a carefully documented test program. At this time, electronic data recording technology was not well developed, so instrument readings were recorded by a movie camera pointed at the instrument panel. Additional movie cameras were carried to record test results.
The first Constitution made a nonstop flight from NAS Moffett Field, California to NAS Patuxent River, Maryland on 25 July 1948, a distance of 2,460 mi (3,960 km). The pilot for the flight was Commander William Collins, USN and the copilots were Lieutenant Commander James W. Robinson, USN and Roy Wimmer, Lockheed engineering test pilot. Four days later, the ship was formally christened by Mrs. John L. Sullivan, wife of the Secretary of the Navy, at Washington National Airport.
The first test flights revealed that the aircraft was underpowered so the engines were changed for 3,500 hp (with water injection) R-4360-22-W engines. The R6O also tested assisted takeoffs with six rockets mounted on the wings near the fuselage. At full gross weight, the rockets shortened the takeoff run by 24%.
Ship No. 1 was delivered to Navy Transport Squadron 44 (VR-44), based at Naval Air Station Alameda, on 2 February 1949. Both it and its sister ship, Ship No. 2 (which followed six months later), flew the route between California and Hawaii, approximately 2,390 mi (3,850 km).
Lockheed R6V Constitution