This EC-121D, Triple Nickel, came to the museum in 1971. It's on display in the Southeast Asia War Gallery.
Lockheed EC-121D
Constellation
The EC-121, originally designated RC-121, was a radar-picket version of the U.S. Air Force's C-121 passenger airplane. The EC-121 provided early warning by detecting and tracking enemy aircraft with the electronic gear in the large radomes above and below its fuselage.
The aircraft on display was nicknamed Triple Nickel because of its serial number (53-555).