06/23/2025. Remarks by Johan Visschedijk: "This Delta 1D-7 was ordered by the US Coast Guard under the designation RT-1 and the serial 382. Powered by a 735 hp Wright SR-1820-F2 Cyclone nine-cylinder air-cooled radial engine, it was delivered to the USCG on February 20, 1935. Initially it was used as the personal transport of Henry Morgenthau, the Secretary of the Treasury, and later as a USCG staff transport, in the mean time it had been reserialed V150.

After an accident, the RT-1 was withdrawn from use in 1940, subsequently it was purchased in damaged condition for $1,400 (original price had been $41,909) by Charles Babb of New York. Licensed NC28663, it was transferred to Airmotive Inc. at Burbank, California, after repairs it was returned to Charles Babb on January 6, 1942. The registration was cancelled on July 30, 1948."