page_title: List of Lockheed Constellation variants
section_title: Military designations
hierarchical_section_title: List of Lockheed Constellation variants / Military designations
caption_attribution_description: English: U.S. Air Force Lockheed EC-121D Warning Star aircraft of the 552nd Airborne Early Warning &amp; Control Wing at Korat Royal Thai Air Force Base, Thailand, during the Vietnam War.
context_page_description: The Lockheed Constellation was an American civil airliner and military transport built in the 1940s and 1950s; this is a list of its variants.
context_section_description: XB-30
  Bomber version of the C-69. Was given model designation L-051 and later L-249.
  XC-69
  Designation for the prototype Constellation. One built. The C-69 was the original military transport version for the USAAF. All aircraft built during World War II were pressed into military service under this designation.
  C-69
  Original troop transport version. Almost all of this type were converted into L-049 airliners. 22 were built.
  C-69A
  Proposed long range troop version of the C-69.
  C-69B
  Proposed long range troop version of the C-69 designed to carry B-29 Superfortress engines to China. Was given model designation L-349.
  C-69C-1
  VIP transport aircraft, later designated ZC-69C-1. Only one aircraft was produced. Was given model designation L-549.
  C-69D
  Proposed VIP transport version.
  XC-69E
  Prototype XC-69 converted into an engine testbed. It was powered by 4 Pratt & Whitney R-2800 Double Wasp engines.
  C-121A
  The C-121 was the military transport version of improved L-749 introduced in 1948. Reinforced floor, cargo door in port rear fuselage
  VC-121A
  VIP transport aircraft, converted from the C-121A
  VC-121B
  VIP transport for use by the President of the United States of America
  C-121C
  R7V-1 with R-3350-34 engines with 3,400 hp (2,536 kW) each, based on L-1049
  JC-121C
  Two C-121C and one TC-121C used as avionics testbeds
  NC-121C
  One C-121C converted for permanent use as a testbed
  RC-121C
  USAF long-range airborne radar analogous to Navy's WV-2
  TC-121C
  Nine RC-121Cs Converted as AEW trainers, subsequently became EC-121C
  VC-121C
  VIP version of C-121C. Total 4.
  EC-121D
  Big Eye/College Eye/Disco early warning variant,  originally designated RC-121D
  NC-121D
  WV-2 converted to observe high speed objects in the atmosphere nicknamed the "Tripple Nipple"
  RC-121D
  WV-2 with wingtip fuel tanks, later redesignated EC-121D
  VC-121E
  VIP transport for use by the President of the United States of America
  YC-121F
  Two prototype R7V-1 with Pratt & Whitney T34-P-6 turboprops with 6,000 shp (4,476 kW) each
  C-121G
  32 Navy R7V-1 delivered to USAF
  TC-121G
  Designation given to 9 C-121G converted into trainers
  VC-121G
  One C-121G given the role as a temporary VIP Transport
  EC-121H
  42 EC-121D with upgraded electronics
  C-121J
  Redesignated Navy R7V-1
  EC-121J
  2 EC-121D with upgraded electronics
  NC-121J
  7 C-121J modified to send television broadcasts to troops in Vietnam
  VC-121J
  4 C-121J converted for VIP use. One served with the Blue Angels.
  EC-121K
  Redesignated Navy WV-2 Warning Star
  JC-121K
  One EC-121K used as an avionics testbed
  NC-121K
  EC-121K used by the Navy
  EC-121L
  Redesignated Navy WV-2E
  EC-121M
  Redesignated Navy WV-2Q
  WQC-121N
  Redesignated Navy WV-3
  EC-121P
  EC-121K equipped for anti-submarine warfare
  EC-121Q
  EC-121D with upgraded electronics
  EC-121R "BatCat"
  EC-121K and EC-121P equipped to process signals from seismic instruments
  NC-121S
  Electronic warfare and reconnaissance version
  EC-121T
  Upgraded radar; One example is on display at Peterson Air and Space Museum, EC-121T photo.
  R7O-1
  The original US Navy designation of the R7V-1 based on L-1049D, R-3350-91 engines with 3,250 hp (2,425 kW) each
  R7V-1
  Re-designation of the R7O-1. Later redesignated C-121J
  R7V-1P
  One R7V-1 modified for Arctic use
  R7V-2
  Four prototypes with Pratt & Whitney YT34-P-12A turboprops of 4,140 shp (3,088 kW) each. Two were delivered as YC-121F prototype aircraft (see above).
  PO-1W
  Two maritime patrol aircraft equipped with search radar based on L-749, later re-designated WV-1.
  PO-2W Warning Star
  Long-range airborne radar aircraft, R-3350-34 or R-3350-42 engines with 3,400 hp (2,536 kW) each, based on L-1049, later re-designated WV-2.
  WV-1
  Re-designation of the PO-1W.
  WV-2 Warning Star
  Re-designation of the PO-2W. Later re-designated EC-121K.
  WV-2E
  Experimental version of WV-2 modified to carry a rotating radar dome similar to that of the Boeing E-3 Sentry. Later redesignated EC-121L.
  WV-2Q
  WV-2 equipped for electronic warfare, later redesignated EC-121M.
  WV-3
  Eight aircraft equipped for weather reconnaissance. Later re-designated WQC-121N.
  XW2V-1
  The XW2V-1 was a planned radar version
caption: A "College Eye" EC-121D at Korat RTAFB.
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