Junkers Jumo 213
| Industry | Aircraft engine manufacturing |
|---|---|
| Founded | 1930s |
| Headquarters | Germany |
| Products | Aircraft engines, including the Jumo 211 and Jumo 213 series |
The Junkers Jumo 213 was a liquid-cooled, inverted V-12 aircraft engine developed during World War II, evolving from the earlier Jumo 211 design by Junkers Motoren. This engine incorporated two significant enhancements: a pressurized cooling system that drastically reduced the coolant volume needed, enabling a more compact and lighter construction, and several refinements that permitted operation at increased RPMs. These advancements raised the power output by more than 500 hp, establishing the Jumo 213 as one of the most coveted engine designs among the Axis towards the war’s end.
Design and development
At the time the Jumo 211 began production in the late 1930s, it employed an unpressurized liquid cooling setup operating on an "open cycle" principle. Water circulated through the engine to dissipate heat but functioned at atmospheric or slightly elevated pressure. Because water’s boiling point decreases with altitude due to lower pressure, coolant temperatures had to remain relatively low at high altitudes to prevent boiling. This limitation reduced the system’s efficiency in extracting heat before the coolant reached the radiator for cooling.
In contrast, the 1940 Daimler-Benz DB 601E featured a pressurized coolant system maintaining consistent pressure regardless of altitude, increasing the boiling point to approximately 110 °C. This innovation allowed for a substantial reduction in water volume while maintaining effective cooling at all altitudes. Although largely similar to the Jumo 211 in other aspects, the DB 601E was more compact and lighter, capable of sustaining higher power outputs at altitude, which made it highly favored for fighter aircraft. Consequently, the Jumo 211 was assigned to secondary roles such as bombers and transport planes.
Dissatisfied with this scenario, Junkers Motorenwerke initiated development of their own pressurized cooling system as early as 1938. Trials conducted on the Jumo 211 demonstrated that not only could water requirements be minimized—resulting in smaller and lighter engines—but also that higher power levels could be achieved without overheating. Reinforcements to the crankshaft and incorporation of a fully enclosed supercharger to enhance boost pressure led to the creation of the Jumo 211F variant, which produced 1,340 PS (1,322 hp, 986 kW) at 2,600 RPM compared to the original 211A’s output of 1000 PS at 2,200 RPM.
213A
The engine block was redesigned to have a more compact external dimension to accommodate enhanced cooling capacity, while retaining the original 150 mm bore and 165 mm stroke dimensions, thus preserving the 35-liter displacement characteristic of the Jumo 211 series. Alongside this, the supercharger's boost pressure was further increased, resulting in the 213A variant producing 1,750 PS (metric horsepower) at 3,250 RPM. This output significantly surpassed the DB 601E’s 1,350 PS and approached the power level of the much larger DB 603, which had a displacement of 44.52 liters. Junkers targeted the market segment served by the DB 603 by designing the 213’s mounting points and fluid connections to match those of the 603, enabling a straightforward replacement installation, except for the supercharger intake positioned on the starboard side in the Jumo design (contrasting with Daimler-Benz's inverted V12 engines that featured port-side supercharger intakes).
The 213A—the primary production model equipped with a single-stage, two-speed supercharger—was first tested in 1940 but faced significant delays before being certified as "production quality" in 1943. Production scale-up was deliberately slow to prevent disruptions to ongoing Jumo 211 manufacturing. By the time substantial quantities were produced in 1944, Allied bombing campaigns frequently interrupted production facilities. Monthly output of the A variant remained limited to approximately 400–500 units throughout most of 1944 and 1945.
Advanced versions
During the extended development phase, several enhanced variants were introduced. The 213B was engineered to operate on 100 octane "C3" fuel, which permitted higher boost pressures and increased take-off power to 2,000 PS. The 213C maintained the A model’s core design but rearranged auxiliary components such as the supercharger and oil pump to accommodate a Motorkanone cannon firing through the propeller shaft. The 213D incorporated a novel three-speed supercharger aimed at delivering smoother power curves and enhanced high-altitude performance; however, despite flight testing prototypes, it never reached production.
The next significant production models were the 213E and its closely related counterpart, the 213F. Both featured a newly developed three-speed, two-stage supercharger that substantially boosted altitude capabilities. The key distinction between these variants was that the E model included an intercooler to further improve high-altitude efficiency, whereas the F model omitted this feature to optimize performance at slightly lower altitudes. These engines were highly sought after for numerous late-war aircraft such as the Junkers Ju 188, Junkers Ju 388, various Langnasen-Dora versions of the Focke-Wulf Fw 190D, and the Focke-Wulf Ta 152H. These aircraft typically utilized annular radiators reminiscent of earlier Jumo 211 installations on twin-engine platforms—often configured as Kraftei (power-egg) modular units designed for rapid installation across multiple airframes—though with radiator designs adapted for more effective cooling of the higher-output Jumo 213.
A major prospective enhancement was planned as the 213J, which would have replaced the previous three-valve-per-cylinder arrangement with a four-valve configuration to improve volumetric efficiency. It was intended to incorporate a two-stage, three-speed supercharger capable of delivering 2,350 hp (1,750 kW; 2,380 PS) at 3700 rpm during take-off and would have weighed approximately 1,055 kg (2,326 lb). Unfortunately, this upgrade did not reach production before hostilities ceased. Additional experimental variants included the low-altitude optimized 213S and the turbocharged 213T.
Postwar development efforts for the Jumo 213 continued at Arsenal de l'Aéronautique in France following Second World War.
Variants
- 213A
- Initial model delivering 1,750 PS (2,100 PS with MW50 boost) at takeoff; served as the primary production variant.
- 213B
- Planned upgrade of the 213A designed to run on C3 fuel (100 octane), capable of up to 2,000 PS takeoff power.
- 213C
- Based on the 213A but modified to mount a cannon firing through the propeller shaft (Motorkanone); produced in limited quantities.
- 213D
- An evolution of the 213C with an advanced three-speed supercharger; this version was never mass-produced.
- 213E
- A high-altitude adaptation of the 213A, equipped with a three-speed two-stage intercooled supercharger, delivering 1,750 PS at takeoff (increased to 2,050 PS with MW50 boost).
- 213F
- Similar to the 213E but replaced the intercooler with MW50 injection for enhanced performance.
- 213J
- A proposed design featuring four valves per cylinder and a two-stage three-speed supercharger, targeting 2,380 PS at takeoff.
- J13T
- A concept for a turbocharged version of the engine.
- Arsenal 12H
- Post-war iteration of the Junkers Jumo 213 produced by Arsenal de l'Aéronautique facilities.
- Arsenal 12H-Tandem
- Configuration combining two 12H engines in tandem to drive coaxial propellers.
- Arsenal 12K
- Further refinement of the Arsenal 12H model.
- Arsenal 24H
- A 24-cylinder H-24 engine utilizing cylinder blocks, crankshafts, and pistons from the 12H series mounted on a new crankcase, powering a single propeller. Rated at 3,600 hp (2,700 kW) for takeoff and 3,000 hp (2,200 kW) at rated altitude.
- Arsenal 24H-Tandem
- Two Arsenal 24H engines coupled in tandem driving coaxial propellers. An example displayed at the 1946 Paris Air Show had a takeoff rating of 7,200 hp (5,400 kW). This configuration was intended for the Sud-Est SE.1200 transatlantic flying boat project, which planned to use four such units each rated at 8,000 hp (6,000 kW).
- SFECMAS 12H
- The Arsenal 12H designation following Arsenal's integration into SFECMAS.
- SFECMAS 12K
- The Arsenal 12K after incorporation into SFECMAS.
Applications
- Heinkel He 111H-22
- Junkers Ju 88
- Junkers Ju 188
- Junkers Ju 388
- Focke-Wulf Fw 190D
- Focke-Wulf Ta 152
- Focke-Wulf Ta 154
- Messerschmitt Me 209-II
- Nord Noroit
- SNCASO SO.8000 Narval
Specifications (Jumo 213E)
See also
Notes
Bibliography
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