Junkers Jumo 213
| Jumo 213 | |
|---|---|
 |
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| Junkers Jumo 213 | |
| Type | Piston inverted V-12 aero-engine |
| Manufacturer | Junkers |
| First run | 1940 |
| Major applications |
Junkers Ju 188 Focke-Wulf Fw 190D |
| Number built | 9,000 |
| Developed from | Jumo 211 |
The Junkers Jumo 213 was a World War II-era V-12 liquid-cooled aircraft engine, a development of Junkers Motoren's earlier design, the Jumo 211. The design added two features, a pressurized cooling system that required considerably less cooling fluid that allowed the engine to be built smaller and lighter, and a number of improvements that allowed it to run at higher RPM. These changes boosted power by over 500 hp and made the 213 one of the most sought-after Axis engine designs in the late-war era.
When the Jumo 211 entered production in the late 1930s it used an unpressurized liquid cooling system based on an "open cycle". Water was pumped through the engine to keep it cool, but the system operated at atmospheric pressure, or only slightly higher. Since the boiling point of water decreases with altitude (pressure) this meant that the temperature of the cooling water had to be kept quite low to avoid boiling at high altitudes, which in turn meant that the water removed less heat from the engine before flowing into the radiator to cool it.
By contrast, the 1940 Daimler-Benz DB 601E used a pressurized coolant system that ran at the same pressure regardless of altitude, raising the boiling point to about 110 °C. This allowed it to use considerably less water for the same cooling effect, which remained the same at all altitudes. Although otherwise similar to the Jumo 210 in most respects, the 601 was smaller and lighter than the 211, and could be run at higher power settings at higher altitudes, making it popular in fighter designs. The 211 was relegated to "secondary" roles in bombers and transports.
The Junkers Motorenwerke firm was not happy with this state of affairs, and started their own efforts to produce a pressurized cooling system as early as 1938. Experiments on the 211 proved so successful that it became clear that not only could the engine be built smaller and lighter (by reducing the water requirement), but could be run at higher power settings without overheating. Additional changes to strengthen the crankshaft and add a fully shrouded supercharger for increased boost resulted in the Jumo 211F model, which delivered 1,340 PS (1,322 hp, 986 kW) at 2,600 RPM, up from 1000 PS at 2,200 RPM in the first version 211A.
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