The Lockheed Y1C-25 'Altair' was the designation given to the first Lockheed Altair when it was purchased by the USAAC.
The Altair was developed from the earlier Lockheed Sirius, a low winged monoplane with a fixed undercarriage produced in response to a request from Charles Lindbergh. At the same time Lindbergh had asked for a spare set of wings that carried a retractable undercarriage. However he then decided not to use them on his own Sirius, and Lockheed decided to fit it to a company demonstrator, aircraft NR119W (Lockheed serial number c/n 153). This had been built with the normal wooden fuselage of the Sirius, and a Wasp C engine. It now gained the new wings, and made its maiden flight in the new configuration in September 1930. The main wheels were mounted fairly wide, and retracted inwards. The outside of each wheel was partly covered with sheets that formed the base of the wing when the undercarriage was retracted.
After six months of being used as a company demonstrator, the Altair was loaned to the USAAC. On 11 April 1931 Captain Ira C. Eaker attempted to break the transcontinental speed record, but had to stop at Port Columbus, Ohio.
Despite this setback the Altair had clearly impressed the Air Corps. During 1931 they purchased a second machine, the sole DL-2 Altair, which had a metal fuselage, and gave it the designation Y1C-23. In November 1931 they also purchased the first Altair, by then powered by a Pratt & Whitney R-1340-17 engine. It became the Y1C-25, gaining a higher 'C' number because it had been purchased second, despite being an earlier design.
The Y1C-25 had a short service career. It was damaged beyond repair after only seven months and 153 flying hours. The Y1C-23 survived much longer, logging 1,075 flying hours before being grounded.
Engines: Pratt & Whitney R-1340-17
Wing span: 42ft 9in
Length: 28ft 4in
Height: 9ft 6in
Gross weight: 5,000lb
Cruising speed: 150mph
Service ceiling: 20,000ft
Normal range: 975 miles
Payload: 400lb/ 1 or 2 passengers