Lockheed 8 Sirius / 8 Altair / Y1C-25 / XRO-1
Detroit Aircraft Corp DL-2

Developed originally to meet a requirement of Charles Lindbergh for a low-wing monoplane of high performance, the Lockheed 8 Sirius combined what was basically a Vega wooden monocoque fuselage with a new low-set cantilever wing. The fuselage is wood laminated and glued, covered with glued plywood. The wings are plywood covered. Ailerons and tail surfaces are plywood covered.

First flown in November 1929, and then powered by a 336kW Pratt & Whitney Wasp radial engine, the Sirius had non-retractable tailwheel landing gear and two open cockpits in tandem. Before accepting this aircraft, Lindbergh had a sliding canopy installed to enclose the two cockpits. In the following year, before Lindbergh set out on a survey flight for Pan American Airways, a 429kW Wright Cyclone engine and twin-float landing gear were installed. For its final survey flight in 1933, it was powered by a 529kW Wright Cyclone engine.

The success of Lindbergh's aircraft led to the construction of 13 more by Lockheed, comprising four similar Sirius 8, eight Sirius 8A with enlarged tail surfaces, and a single four-seat Sirius 8C aircraft which had an enclosed cabin for two between the engine and pilot's cockpit. One Sirius built by the Detroit Aircraft Corporation, with a metal fuselage and Lockheed wooden wing, had the designation DL-2 Lindbergh's Sirius spanned 13.04m, weighed a maximum of 3220kg, was capable of a maximum of 298km/h, and had a range of 1570km, all in landplane configuration.

When acquiring his Sirius, Charles Lindbergh had intimated that he might be interested in having retractable landing gear, with a result that the company designed an alternative wing to accept inward-retracting main landing gear units. Although this feature was not adopted by Lindbergh, it became available as a retrofit for Sirius aircraft, first flown on a company-owned Sirius 8A during September 1930. Redesignated Lockheed Altair 8D in this form, the aircraft was loaned to the US Army Air Corps during 1931 and in November of that year, with a new 336kW Pratt & Whitney R-1340-17 engine installed, was acquired by the USAAC under the designation Y1C-25.

Four more aircraft were converted, two Sirius 8As becoming Altair 8D aircraft, the Detroit Aircraft DL-2 being redesignated Altair DL-2A and, most famous of all, one Sirius receiving the designation Sirius 8 Special. This last aircraft was later acquired by Sir Charles Kingsford Smith and, modified to Altair 8D configuration and named Lady Southern Cross, was used by this pilot, with P. G. Taylor as his navigator, to make the first crossing of the Pacific Ocean from Australia to the United States between 20 October and 4 November 1934.

In addition to the conversions, six Altairs were built as new, one of them an Altair DL-2A built by Detroit Aircraft and powered by a 481kW Wright R-1820E Cyclone which was acquired by the US Navy under the designation XRO-1.

Pontoon fuel capacity: 300 gal

Sirius 8
Wing span: 13.04m
Maximum weight: 3220kg
Maximum speed: 298km/h
Range: 1570km

Sirius 8A

Sirius 8C
Seat: 4

Altair 8D / Y1C-25
Engine: 336kW Pratt & Whitney R-1340-17

Detroit Aircraft Corporation DL-2 / Altair DL-2A / XRO-1
Engine: 481kW Wright R-1820E Cyclone
Max take-off weight: 2220 kg / 4894 lb
Wingspan: 13.03 m / 42 ft 9 in
Max. speed: 333 km/h / 207 mph