The C-121 Constellation is a long-range tactical military transport aircraft, developed by the American firm Lockheed. The Lockheed Model 49 aircraft was initially conceived as a 40-seat airliner for domestic routes, making its first flight on January 9, 1943.
Origins and Wartime Service
During World War II, all production aircraft were directed to the U.S. Army Air Forces, serving as transports under the designation C-69 Constellation. Following the war, Lockheed introduced a new modification, the Lockheed Model 749, in 1948. This model served as the basis for the improved C-121 Constellation transport aircraft.
Key Variants and Specialized Roles
The C-121 Constellation family saw numerous adaptations for various roles. An L-749 variant, designated VC-121A, was modified for US Air Force personnel transport with a reinforced floor and a left-side cargo door in the aft fuselage, often featuring VIP cabins.
Specific presidential aircraft were also developed, including one L-749-based VIP cabin aircraft and later, another dedicated VIP aircraft. Two L-749 airframes were equipped with onboard long-range radar, marking the Constellation’s foray into airborne early warning.
Further developments included the L-1049D variant for the US Navy (later R7V-1, then C-121J), powered by Wright R-3350-91 Turbo-Compound engines. Experimental versions included one R7V-1 for polar glacier research and four aircraft with Pratt & Whitney YT34-P-12A turboprop engines (4139 shp).
Advanced radar platforms, based on the L-1049 airframe, were equipped with powerful Wright R-3350-34 or R-3350-42 Turbo-Compound engines. The WV-2 series, analogous to USAF radar aircraft, were later re-equipped for electronic countermeasures (ECM) and saw variants with wingtip fuel tanks and modified layouts.
Many C-121s were redesignated as EC-121s, specializing in electronic roles. This included 32 R7V-1 aircraft transferred from the Navy to the USAF, and 42 EC-121D aircraft with special electronic equipment, including additional gear for electronic and aircraft systems research. EC-121K aircraft were utilized by the US Navy for various tests, anti-submarine operations, and data processing from seismic instruments. Other specialized variants served for electronic warfare (ECM) and electronic intelligence, with modifications to enhance radar capabilities.
Technical Specifications
| Modification | C-121C |
| Wingspan, m | 38.47 |
| Length, m | 35.42 |
| Height, m | 7.54 |
| Wing area, m2 | 153.66 |
| Empty weight | 36152 |
| Maximum takeoff weight | 65772 |
| Internal fuel, l | 17755 |
| Engine type | 4 Piston engine Wright R-3350-DA3 |
| Thrust, kN | 4 x 3300 |
| Maximum speed, km/h | 570 |
| Cruising speed, km/h | 510 |
| Practical range, km | 8200 |
| Operational range, km | 5340 |
| Practical ceiling, m | 7620 |
| Crew, crew | 5 |
| Payload | 71-91 passengers |
Image and diagram gallery of the C-121 Constellation
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