POWER: EARLY: 2 x Hispano-Suiza 12Z engines (tandem) driving contra-rotating propellers; ORIGINAL: 1 x Hispano-Suiza 24Z engine developing 3,600 horsepower driving six-bladed contra-rotating propeller at the nose; LATER: 1 x Arsenal 24H engine developing 4,000 horsepower and driving five-bladed propeller at the nose.
French aero-industry faced all manner of disruption with the arrival of World War 2 in 1939. With the fall of France in May-June of 1940, many projects were cancelled, shelved or turned over to the Germans for the foreseeable future. The SNCASE / Sud-Est SE.580, arriving as a potential high-powered fighter for the French Air Force and Navy services, was one product that managed to eke out an existence prior to, during and after the war. However, technical issues and outside influences soon doomed the project as the 1940s wound down.
The SE.580 began life from design studies undertaken by SNCAM in 1940 and was then known as the M.580. When the company was taken over by SNCASE (Sud-Est), the designation was revised to become SE.580. Work on the product was slow due to the German invasion and much slower during the occupation period. Wind tunnel testing was finally had in 1943 and, at this stage, the aircraft was envisioned to possess a pair of Hispano-Suiza 12Z series engines seated in line and driving a contra-rotating propeller unit at the nose. Beyond this, the aircraft was given modern features such as a retractable undercarriage, enclosed cockpit and low-set monoplane wings. All-metal construction would greet its makeup while control surfaces were be finished in fabric. A major design element proving unconventional to aircraft of the age was a large dorsal scoop positioned immediately behind the cockpit to cool the radiator fit. Excess air would be exhausted through a ventral port.
As the SE.580 was to fulfill the role of dedicated fighter, able to match toe-to-toe against anything the Germans possessed at this stage, the aircraft would be armed through 1 x 30mm automatic cannon firing through the propeller hub and 4 x 20mm automatic cannons (2 per wing) coupled with 8 x 7.5mm machine guns (4 per wing) found at each wing. This armament battery was rather considerable when compared to contemporaries and gave the fighter a viable punch against enemy fighters and larger bomber types. There was also provision had for underwing hardpoints (one per wing) to which each station could manage up to 1,100lb in conventional drop ordnance.
During development, the decision was made to move on from the proposed tandem engine arrangement to a single engine installation. This became the Hispano-Suiza 24Z (24-cylinder) engine of 3,600 horsepower output (the contra-rotating propeller was still in play).
From this promising work emerged a French Air Force contract for two prototypes and this was followed for a separate commitment by the French Navy for another pair of aircraft to trial as the SE.582. With the end of the war coming in 1945, work on the SE.580 series continued into 1946 though technical issues with the intended engine fit forced engineers to select the Arsenal 24H series engine of 4,000 horsepower output in its place. This inevitably led to alterations being forced on the fuselage to accommodate the new powerplant and the contra-rotating propellers were given up in favor of a simpler single five-bladed unit. Despite the work already had on the design, these issues as well as the rise of jet-powered military fighters, led to the cancellation of the SE.580/SE.582 in 1947.
As designed, the SE.580 had estimated performance figures that included a maximum speed of 465 miles per hour (30,500 feet), a service ceiling of 44,620 feet, a range out to 1,710 miles and a rate-of-climb nearing 3,280 feet-per-minute.