This aircraft is widely quoted as XB-DUZ, but it was in fact XB-QUZ (see this photo). When this Conestoga arrived at Pima in 1978, the reg had faded considerably, with the tail of the 'Q' almost entirely gone. Also the 'Q' was very square in shape, making the reg appear to read as XB-DUZ. In this photo traces of the registration are still visible on the rear fuselage. Delivered to the US Navy as Bu39307 on 19 Oct 1944, but not operated by them. Sold to National Skyway Freight / Flying Tiger Line as NC33308 In Jul 1945, then as XB-QUZ in 1948. Impounded in the mid 1960s and stored at Douglas, AZ until sold to Ned Robinson on 23 Aug 1972. He donated it to the Pima Air Museum in Jul 1978.

Delivered to the US Navy as J4F-2 Bu32976 on 21 Sep 1943. Transferred to Edo Aircraft Corp in Jan 1947 for hull development work. Went through several hull designs, of which this was the last one. The converted Widgeon was nicknamed "Petulant Porpoise" in early 1948, and loaned to NACA (later NASA) from 28 Feb 1950 until 8 Jun 1953. Effective 15 Dec 1952 the US Navy consistently used the non-standard type designation E-175 for this aircraft. Struck off charge 8 Feb 1956 (total time 975 hours) and stored at Norfolk NAS, VA. Delivered to the National Air Museum (Smithsonian) on 15 Sep 1960, but kept in storage. To the Fighter Aircraft Museum on 14 Feb 1977, and again kept in storage. Loaned to the Pima Air Museum in 1987.

Registration widely misquoted as XB-DUZ.

Recently X-15 replica "56-6670" was mounted under the right wing