In the early forties Pan American Airways was interested in large long-range airliners to be
operated on the extensive network under contract to the War and Navy Departments. Boeing,
Convair, Douglas and Lockheed all started with their initial designs in 1942, the first
three were supported by the USAAF leading to the XC-97, XC-74, XC-99; the US Navy supported
Lockheed with their Model 89 and ordered two prototypes.
Due to other and higher priorities the first Lockheed 089 XR6O-1 Constitution (BuNo.
85163, c/n 089-1001) flew not until November 9, 1946. It was powered by four 3,000 hp
R-4360-18 but these were soon replaced by the 3,500 hp R-4360-22W with water injection. The
second aircraft (BuNo. 85164, c/n 089-1002) flew with the R-4360-22W engines, for the first time
in June 1948.
At the moment of its first flight the Constitution was the largest transport aircraft ever
flown and had apart from its size some other novelties. The fuselage cross-section was a
"double-bubble" which allowed for two approximately equally-sized pressurized cabins, these
being interconnected by spiral staircases. In the normal airline configuration there was
place for 168 passengers, in maximum density configuration 204 military personnel could be
seated, and there was a galley for preparing food for over 200 people.
In the mixed version passengers were carried on the upper deck with cargo on the lower deck
loaded through cargo doors fore and aft of the wing. Other novelties were: large depth of
the wings allowing access to the engines during flight; hydraulic and electric control
centers with fully equipped workshop located in center section of wing; main landing gears
consisted of two two-wheeled struts on each side of the fuselage, the wheels were
pre-rotated to landing speed just prior to landing.
Already before the first flight Pan American decided not to buy the Constitution, but the
two aircraft entered US Navy service in respectively February and August 1949. Still
underpowered the fully loaded the range was 2,400 mls (3,862 km) instead of the expected
6,300 mls (10,139 km).
The cooling of the engines was a major problem, to solve this the cowl flaps were kept
partially open during flight, this increased the drag of the already underpowered. In 1950
the Manufacturers Code for Lockheed changed from "O" to "V" and the Constitution was
In 1953 the US Navy retired the two aircraft storing them at Litchfield Park, Arizona, being
sold in 1953 to separate buyers; one flew to Las Vegas, Nevada and the other to Opa Locka,
Florida. The latter received there the civil registration N7673C but a fire destroyed its
interior and finally both aircraft never got their civil type certification, never left the
ground again and were finally scrapped.