North American P-51 Mustang (N51NA)

This Mustang is one of only two (1 of 2) XP-51 types built... and powered by an Allison engine...!!! :-)

https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=51NA

From Joe Baugher's published information...

"41-038/039, North American XP-51 Mustang".

"038 (MSN 73-3101) was originally allocated to RAF as AG348 but was not delivered. The serial AG348 was reallocated to NA-73 Mustang I MSN 73-3100 which was a direct purchase by RAF that did not have USAAF serial. Assigned to Wright Field, Ohio. Assigned to NACA Langley Memorial Aeronautical Laboratory, Virginia Dec 28, 1941 to Nov 2, 1942. Assigned to Wright Field, Ohio. Assigned to NACA Langley Memorial Aeronautical Laboratory, Virginia Jan 11, 1944 to Jul 25, 1945. Assigned to Freeman Field, IN. US Aircraft Section, Air Materiel Command, Freeman Field, Seymour, Indiana. Set aside for proposed USAAF aviation museum. Flown to the aircraft storage area, 803rd Special Depot at Orchard Place Airport, Park Ridge, Illinois May 1946. Went to NASM in 1950, first to Park Ridge, IL then to Silver Hill, MD. To EAA Aviation Foundation of Oshkosh, WI in 1975, registered as N51NA."

http://www.joebaugher.com/usaf_serials/1941_1.html

WOW! The XP is the prototype notation, but there was another --
The North American A-36 Apache ...
was the ground-attack/dive bomber version of the North American P-51 Mustang, from which it could be distinguished by the presence of rectangular, slatted dive brakes above and below the wings. A total of 500 A-36 dive bombers served in the Mediterranean and Southeast Asia theaters during World War II before being
withdrawn from operational use in 1944.

See https://en.wikipedia.org/wiki/North_American_A-36_Apache#Specifications_(A-36A)