This is a Hispano-Suiza 12XCRS V12 engine from 1935, it has a displacement of 27 liters and an output of 690 bhp – this was an astonishing figure for an engine at the time, a period when most “normal” engines produced considerably less than 100 bhp.
The 12XCRS V12 was developed an an aircraft engine, it has a 60º V-angle designed to accommodate a machine gun barrel down the center, which would then fire rounds right through the center of the propeller shaft – eliminating the need to synchronize firing with propeller rotation.
Many aircraft from the period, including the highly unusual Blériot-Zappata 110, were powered by various Hispano-Suiza engines. Image courtesy of Hispano-Suiza.
History Speedrun: The Hispano-Suiza 12XCRS V12
The Hispano-Suiza 12Xcrs is a supercharged 60° V12 aircraft engine designed in France during the early 1930s by the legendary Swiss engineer Marc Birkigt. It was a critical step in European aviation, combining formidable power output with one of the era’s most innovative armament concepts – the moteur-canon, a system that allowed a 20mm Hispano-Suiza S7 cannon (an Oerlikon-licensed design that preceded the later HS.404) to be mounted between the cylinder banks and fire directly through the hollow propeller shaft.
This firing arrangement eliminated the need for a synchronization gear and gave pilots a centrally aimed, hard-hitting weapon, a feature that would define French fighter design throughout the decade up until the start of WWII in 1939.
The 12XCRS V12 engine displaced 27 liters (1,648 cubic inches) from a bore and stroke of 130mm × 170mm, and it had a single overhead cam per bank operating two valves per cylinder. Cast aluminum was used for much of the engine’s construction, reducing weight and also helping a little with cooling.
Running on 85 octane fuel fed by six Solex carburettors, with a compression ratio of 5.8:1 and a single-speed centrifugal supercharger geared at 10:1, the engine produced a rated 690 bhp at 2,600 rpm at its optimum supercharger altitude of 4,500 meters.
The engine’s take-off power was slightly lower at 660 bhp, and the propeller was driven through a 2:3 spur-type reduction gear. Despite its formidable output, the engine weighed just 380 kgs (838 lbs), giving it a power-to-weight ratio of 1.34 kW/kg. The engine’s designation itself was encoded with its key features “c” for cannon-equipped, “r” for reduction geared, and “s” for supercharged.
This is a blueprint illustration of an Hispano-Suiza V8 aero engine, showing a familiar layout shared with many of the V12s. Image courtesy of Hispano-Suiza.
Introduced in 1934, the 12Xcrs powered the Dewoitine D.501 aircraft, a variant of the D.500 series that became the first low-wing cantilever monoplane fighter to enter French Air Force service. The D.501 carried the engine’s 20mm cannon firing through the propeller hub alongside wing-mounted machine guns – this was a potent arrangement for the time.
Other aircraft fitted with 12X variants included the Blériot-SPAD S.510 (though production S.510s predominantly used the non-cannon 12Xbrs), the Loire 130 flying boat, the Potez 540, and even the Japanese Nakajima Ki-12 experimental fighter.
Of the D.500 family, some 258 D.500 and D.501 airframes were powered by 12X-series engines, while the later D.510 (of which 120 were built) adopted the more powerful Hispano-Suiza 12Ycrs, displacing 36 litres and producing 860 bhp.
Though it was eventually outclassed by the larger engines that followed, the 12Xcrs sits in an important place in aviation history. It’s the engine that proved the viability of the moteur-canon concept that would carry forward into France’s front-line fighters of the Second World War, and it demonstrated that a compact, well-engineered powerplant could deliver nearly 700 bhp reliably at altitude, it’s hard to overstate how much of a remarkable achievement this was for the mid-1930s.
The 1935 Hispano-Suiza 12XCRS V12 Shown Here
The engine you see here is an original Hispano-Suiza 12XCRS V12 from 1935, just four years before the outbreak of WWII. The engine appears to be largely complete, though it is missing a few important parts, and as a result it isn’t currently in running or operable condition.
The engine you see here is an original Hispano-Suiza 12XCRS V12 from 1935, just four years before the outbreak of WWII. The engine appears to be largely complete, though it is missing a few important parts, and as a result it isn’t currently in running or operable condition.
This 12XCRS comes with the block, barrels, and cam covers all in place, but the listing doesn’t mention if it contains its internal parts or not. We can see from the pictures that the ignition system is largely accounted for, as well as the supercharger, though of course the original gun is not included.
This engine is now due to be offered by Aguttes as part of the Collector Aircraft & Automobiles Spring Sale in mid-March, and you can visit the listing here if you’d like to read more about it or register to bid.
Images courtesy of Aguttes
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Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
