The registration NL51WT was carried in small letters under the tailplane, and the name "Nervous Energy IV" was carried on the left hand side of the engine cowling. Originally serial 45-11391 with the USAAF, it carried the civilian registrations N6170C and N5151N before being registered N51WT in 1977. In March 2002 it was re-registered N51MV/NL51MV and now flies out of Scottsdale, AZ., as "Nervous Energy V".