Hispano-Suiza Type 89

The 12Z, designated Type 89 by the company, was the final evolution of the series of Hispano-Suiza V-12 aircraft engines. The Z model had just entered production when France fell to the Germany, Germans during World War II. A small number were produced during the war but the German occupation government would not allow full-scale production to start. After the war small numbers were built to equip new designs, but the rapid introduction of the jet engine ended further development.

Design and development

The 12Z differed from the earlier Hispano-Suiza 12Y, 12Y primarily in the use of four valves per cylinder operated by dual overhead cams, as opposed to two valves operated by a single camshaft. This gave the cylinders considerably better volumetric efficiency and faster operation, raising the RPM from 2,400 to 2,700. The engine was also designed to run only on 100 octane rating, octane fuel (instead of 87, which was common at that point) which allowed the compression ratio to rise from the 12Y's 5.8:1 to the 12Z's 6.75:1. These changes raised the power from 1,000 to 1,300 hp (750 to 970 kW) at sea level.

The engine continued to use a single-stage, single-speed supercharger and therefore lacked the all-altitude performance of German and British designs. But tuning the supercharger for a different critical altitude improved high-altitude performance considerably, delivering 1,500 hp (1,120 kW) at as opposed to 930 hp (690 kW) at for the 12Y.

Small prototype runs started in 1939, and were fitted to the List of aircraft of the French Air Force during World War II, French Air Force's front-line fighter aircraft, the Morane-Saulnier M.S.406, M.S.410 and Dewoitine D.520, D.520, creating the M.S.450 and D.524 respectively. Production of the main model, the 12Z-17, was just starting at the time of the Armistice with France (Second Compiègne), armistice. Production was undertaken in Hispano-Suiza's Spain, Spanish factories where they were intended for the Hispano Aviación HA-1112 - only a few were ever used, however, because of mechanical problems with the engine.

After the war a new version tuned to operate with 92 octane rating, octane fuel, as opposed to the -17's 100/130, was built in limited numbers as the 12Z-89. Compression ratio was raised slightly to 7:1, but with the lower grade fuel the power dropped slightly to 1,280 hp (950 kW) at 2,600 rpm (1,479 hp (1,100 kW) maximum take-off). These engines apparently had the same sorts of reliability issues as the earlier -17's made in Spain, and the type never entered production.

Variants

;12Z-1
:The initial version of the engine used for development
;12Z-17
:development peak at time of the Fall of France in May 1940
;12Z-89
:post-war development, not successful.

Applications

* Arsenal VB 10
* Breguet 482
* Hispano Aviación HA-1112
* Ikarus S-49C

Specifications (12Z-1)

See also

References

External links

"Hispano Suiza 12B"
a 1949 ''Flight'' article

{{DEFAULTSORT:Hispano-Suiza 12z
1930s aircraft piston engines
Hispano-Suiza aircraft engines