Another rare and historically significant aircraft has been listed for sale by Platinum Fighter Sales. The 1944 North American P-51D Mustang Sierra Sue II is a documented 9th Air Force combat veteran and one of only a handful of flying Mustangs that saw active service during World War II. Assigned to the 402nd Fighter Squadron, 370th Fighter Group, 9th Air Force, the aircraft served in the European Theatre in 1945. Its regular pilot, 1st Lt. Robert “Bob” Bohna, named the Mustang Sierra Sue II after a girl he knew in high school. In 2014, the aircraft underwent a meticulous restoration by AirCorps Aviation in Bemidji, Minnesota, returning it to its 1944 factory-delivery configuration. Authentic wartime features— including operational WWII-era radios and full armor plating—were faithfully restored.
On 5 November 1944, P-51D Mustang 44-63675 was formally accepted by the U.S. Army Air Forces. It was delivered on 27 November and shipped to Belgium on 29 January 1945. In early April 1945, it joined the 402nd Fighter Squadron and was coded ED-6. Lt. Bohna flew the aircraft through the final months of the war under the name Sierra Sue II.
In 1947, the aircraft was sold to the Swedish government as part of one of the last P-51 purchase lots. Re-designated as a J26 and assigned serial Fv26152, it arrived at F4 Östersund in June 1948 and served in the third (yellow) squadron. Painted with a yellow “K” on its tail, it quickly earned the nickname “Gul Kalle”—“Yellow K.” Pilot Sten Söderquist flew the Mustang for four years. In October 1952, the aircraft was transferred to F8 near Stockholm to serve as a staff aircraft. Its tail marking was repainted green, earning the new nickname “Grön Kalle,” or “Green K,” and the name “Kleopatra” appeared on its nose. On 18 September 1952, the Mustang was sold, disassembled, and shipped via the port of Malmö to Nicaragua. Reassembled at Las Mercedes Air Base near Managua, it entered service as GN91 with the Nicaraguan Air Force. The aircraft was retired in 1961 and later placed on outdoor display at Las Mercedes.
On 30 July 1971, the Nicaraguan Air Force sold GN91 to Dave Allender of San Mateo, California. Registered as N5452V and racing under the number 19, the Mustang received numerous modifications and a bright red paint scheme. On 8 March 1977, it was sold to Roger “Doc” Christgau of Austin, Minnesota. Between 1977 and 1983, Jack Cochrane of Hollister, California fully restored the aircraft to stock Mustang configuration. The FAA registration changed to N1751D in October 1979. In May 1983, the Mustang relocated to Minnesota and was later repainted as Sierra Sue II, featuring wartime markings on the left side and Swedish “Gul Kalle” markings on the right. Christgau owned the aircraft for more than 30 years and became a familiar figure on the airshow circuit throughout the 1980s and 1990s. On 1 July 2011, the aircraft was sold to Paul Ehlen of Hamilton, Montana, who sent it to AirCorps Aviation for a complete, factory-specification restoration. On 17 September 2014, Sierra Sue II made its first post-restoration flight. In May 2015, it joined the Wings of the North collection as a centerpiece of the new museum. The Mustang was purchased by its current owner in January 2024 and is now based in Scottsdale, Arizona.
Sierra Sue II is widely regarded as the most original and authentically restored P-51D Mustang flying today. During the restoration, AirCorps Aviation confirmed that only the engine mount, ailerons, and flaps were not original to the airframe as it left the North American factory in Inglewood, California, in 1944. The three-year restoration recreated the aircraft exactly as it appeared in April 1945, with meticulous attention to the smallest historical details. Original equipment—including the fuselage fuel tank, armor plating, and demilitarized armament—was reinstalled, making this Mustang as close to a combat-ready P-51D as exists in the world. Following the restoration, Sierra Sue II flew to EAA AirVenture Oshkosh, where it earned the 2015 Reserve Grand Champion WWII Award and received a Golden Wrench Award for AirCorps Aviation. For more information about this airplane, visit www.platinumfighters.com.
