c/n 1961
Model 49-46-10 Constellation Prototype NX25600

                                                                                                                    Lockheed Archives

Construction started 1940 and completed November 1942. Painted in USAAF camouflage with military star and civil test registration. First flight 9 January 1943 from Burbank, CA, with Edmund T. Allen and Milo Burcham at the controls, lasting 58 minutes.

 Model 049S Super Constellation Prototype N67900

                                                                                                                       Lockheed Archives

Bought back by Lockheed for $100 000 on 1 May 1950 (Total Time 404 hrs) and registered NC25600. Converted to Super Constellation Prototype at Burbank during summer 1950.
First flight 13 October 1950 with Jim White and Ray Meskimen at the controls.

This aircraft was used for various modifications during its life time:

    Early 1951                      new Wright R3350-CA engine was fitted in no. 4 position, outboard 
    vertical stabilizers enlarged by 18 inches to improve directional control

    1951                               stepped roof cockpit installed

    Late 1951                       first prototype R-3350 Turbo Compound engine installed

    1952                              the aircraft was fitted with two 600 US Gallon wing-tip tanks (in preparation for the turbo prop development)

    1952                              R3350-CA was replaced by the updated CB engine

    1952                              Aero-dynamic tests for the Navy airborne early warning version Super Constellations

    1953                              DA-1 engines installed and used as test bench to sort out the various problems with the Turbo compound engines

    1954                              Allison YT-56 (for the C-130 Hercules) was installed in the no. 4 position, c/n changed to 1961ST; DA.-3 and EA-1 engines were fitted, the latter for the Model 1649 Starliner in 1956

    1957                              Allison 501 D13 was tested for the Model188 Electra

    End 1957                       "old 1961" was withdrawn from use by Lockheed

    1958                              parts used for the rebuild of c/n 2513, remains scrapped later

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