Sunday, 17 January 2016

Heinkel He111. Powerplant. Part 5. German Dzib -Compiler-


He111 H-6

Junkers Jumo211

The Jumo 211 was an inverted V-12 aircraft engine, Junkers Motoren's primary aircraft engine of World War II. It was the direct competitor to the famous Daimler-Benz DB 601 and closely paralleled its development. While the Daimler-Benz engine was mostly used in single-engined and twin-engined fighters, the Jumo engine was primarily used in bombers such as Junkers' own Ju 87 and Ju 88, and Heinkel's H-series examples of the Heinkel He 111 medium bomber. It was the most-produced German aero engine of the war, with almost 70,000 examples completed.

In February 1937, the German Condor Legion began flying in Spain, in support of Franco's Nationalists in the Civil War. The B-2, equipped with 950hp DB 600CG engines, met considerable success in this conflict, infamously with the indiscriminate bombing of Guernica in July. As a result, the Luftwaffe drew exaggerated conclusions from this experience, thinking that masses of medium bombers like the He 111 would be irresistible. In fact, even the vastly more lethal four-engine heavy bombers of the U.S. Eighth Air Force were not sufficient, by themselves, to bring an industrial country to its knees.
Pitomnik airstrip, in German Stalingrad pocket, early January, 1943. (2)

Design and development

The Jumo 211 was developed by Dr. Franz Josef Neugebauer as scaled-up successor to the earlier Jumo 210. In 1934, even before the new Jumo 210 had completed its acceptance tests, the RLM sent out a request for a new 1,000 PS-class engine of about 500 kg weight. Both Jumo and Daimler-Benz responded, and in order to reach service before the new Daimler-Benz DB 600, the Jumo team decided to make their new design as similar as possible to their 210H model, currently in testing.
The resulting Jumo 211 was first prototyped at Jumo's Dessau plant in 1935 and started testing in April 1936. Like the 210H, it featured a mechanical direct fuel injection system using small pistons driven off the crankshaft, three valves per cylinder, and an inverted V layout. It also had an open-cycle cooling system, not pressurized, as was the case on the later 213. (78) Limited production of the 1,000 PS (990 hp; 740 kW) Jumo 211A started in April 1937 at Dessau, with just over 1,000 completed before full production was started at Magdeburg in July. Three models were provided with varied settings for its two-speed supercharger, tuned for different low- versus high-altitude performance.
Junkers Jumo 211B/D engine at the Luftwaffen museum der Bundeswehr
The first prototype aircraft powered by the 211A appeared in late 1937. Development of the 211 continued with the 211B being released in 1938, with a slightly increased maximum RPM of 2,400 which boosted power to 1,200 PS (1,200 hp; 880 kW). The later 211C and 211D differed primarily in the propeller gear ratios and other features.
A major upgrade was started in 1940 in order to better compete with the 601, following in its footsteps with a pressurized cooling system. The resulting 211E proved to be able to run at much higher power settings without overheating, so it was quickly followed by the 211Fwhich included a strengthened crankshaft and a more efficient supercharger. Running at 2,600 RPM the 211F delivered 1,340 PS (1,320 hp; 990 kW) and the 211J (a 211F with intercooler) 1,420 PS (1,400 hp; 1,040 kW). Further improvements to this basic line led to the 1,450 PS (1,430 hp; 1,070 kW) 211N and 1,500 PS (1,500 hp; 1,100 kW) 211P in 1943, they were equivalent to the 211F/J but with slight boost increases and running at up to 2,700 rpm. Continued development of the 211 line evolved into the Jumo 213.
The Jumo 211 became the major bomber engine of the war, in no small part due to Junkers also building a majority of the bombers then in use. Of course, since it was the Luftwaffe that selected the final engine to be used after competitive testing on prototypes (such as the Dornier Do 217), there is certainly more to it. Limited production capacity for each type, and the fact that the Jumo was perfectly capable (if not superior) in a bomber installation meant that it made sense to use both major types to the fullest; since the Daimler had a slight edge in a lightweight, single-engine application, that left the Jumo to fill in the remaining roles as a bomber engine. Even this wasn't enough in the end, and radial engines like the BMW 801 were increasingly put into service alongside the Jumo and DB series, most often in multi-engine installations like the Jumo. Total production of the 211 series amounted to 68,248 engines, including 1,046 prototypes and development engines, with a production peak of 1700 engines per month in the autumn of 1942. From 1937 to mid-1944, production was spread between factories in  Magdeburg, Köthen, Leipzig, Stettin and Strasburg. (79)
The Me 264 V1 Amerika Bombercontract competitor fitted with four unitized Jumo 211 engines, each one matching the type fitted to Ju 88As
It was the most-produced German aviation engine of the World War II years, and was quite likely to have been the first model of German aviation engine selected for "unitizing" as a Kraftei pre-packaged "engine module" — such Kraftei units for the Ju 88A were, as one example, used as the initial quartet of powerplants to power the Messerschmitt Me 264 V1 Amerika Bomber contract competitor into the air in December 1942.


Powers and rotational speeds are for take-off at sealevel. (79)
Engine model
Power in PS
Power in hp
Power in kW
Power at rpm
A (early)
A (late)


             Avia S-199
             Dornier Do 217 - single engine test aircraft 
             Focke-Wulf Ta 154
             Heinkel He 111E, H and Z
             IAR 79
             Junkers F 24kai Jumo 211 test bed
             Junkers Ju 87
             Junkers Ju 88
             Junkers Ju 90
             Junkers Ju 252
             Messerschmitt Me 264 (V1 prototype only)
             Messerschmitt Me 323 (only for tests)
             Savoia-Marchetti SM.79 (Romanian variants)

Specifications (Jumo 211 C)

Jumo 211F

General characteristics (80)

             Type: Twelve-cylinder supercharged liquid-cooled 60-degree inverted V piston aircraft engine
             Bore: 150 mm (5.91 in)
             Stroke: 165 mm (6.5 in)
             Displacement: 34.99 l (2,135.2 in³)
             Length: 1,768 mm (69.61 in)
             Width: 804 mm (31.65 in)
             Height: 1,050 mm (41.34 in)
             Dry weight: 585 kg (1,290 lb)


             Valvetrain: Overhead camshaft, 3 valves per cylinder
             Supercharger: Two-speed centrifugal type supercharger with automatic boost control
             Fuel system: direct fuel injection
             Fuel type: 87 octane rating gasoline
             Cooling system: Liquid-cooled, ethylene glycol
             Reduction gear: Spur, 1.55:1


             Power output:
             736 kW (1,000 PS or 986 hp) at 2,200 rpm for takeoff
             754 kW (1,025 PS or 1,011 hp) at 2,200 rpm at 1,710 m (5,610 ft), first supercharger speed
             718 kW (975 PS or 962 hp) at 2,200 rpm at 4,200 m (13,780 ft), second supercharger speed
             Specific power: 21.54 kW/l (0.47 hp/in³)
             Compression ratio: 6.5:1 
             Specific fuel consumption: 322-335 g/(kW•h) (0.53-0.55 lb/(hp•h))
             Oil consumption: 11-16 g/(kW•h) (0.28-0.42 oz/(hp•h))
             Power-to-weight ratio: 1.29 kW/kg (0.78 hp/lb)

HE 111 C0 (81)

The BMW VI was a water-cooled V-12 aircraft engine built in Germany in the 1920s. It was one of the most important German aero engines in the years leading up to World War II, with thousands built. It was further developed as the BMW VII and BMW IX, although these saw considerably less use. It was also produced in the Soviet Union and Japan as the Kawasaki Ha-9.
Design and development
The BMW VI was the first twelve-cylinder engine built by the BMW. It essentially consisted of two cylinder banks from the six-cylinder BMW IV bolted to a common cast aluminium crankcase at a 60-degree included angle between the cylinder banks. Series production commenced in 1926 after type approval had been granted. From 1930 on, after 1000 engines of the BMW VI type had already been delivered, Germany was again permitted to construct military aircraft. The sudden additional demand resulted in the production figures increasing rapidly. In 1933 the BMW VI was used for BMW's first experiments with direct fuel injection.
The BMW VI was the chosen source of power for numerous record-breaking and long-distance flights, including an east-to-west crossing of the Atlantic in 1930 and a round-the world flight in 1932, both by Wolfgang von Gronau in an open Dornier Wal flying boat powered by two BMW VI engines.
The BMW VI was put to unusual use as a power unit for the "Rail Zeppelin" high-speed railcar. Many versions of the BMW VI engine were developed, and it was built under license in Japan and the Soviet Union. This was further evidence of the reliability of an engine with which BMW made a fundamental contribution to the build-up of German air transport. At least 9,200 were built between 1926 and 1938. The engine was license-built in the Soviet Union under the supervision of Mikulin, who then further developed it as the M-17. More license built engines were produced by Kawasaki Heavy Industries in Japan as the Kawasaki Ha-9.


             Albatros L 77
             Arado Ar 64
             Arado Ar 65
             Arado Ar 68
             Arado SSD I
             Dornier Do 10
             Dornier Do 14
             Dornier Do 17
             Focke-Wulf Fw 42
             Heinkel He 45
             Heinkel He 51
             Heinkel He 59
             Heinkel He 60
             Heinkel He 70
             Heinkel He 111
             Junkers F.24ko
             Kawasaki Type 92
             Polikarpov R-5 prototype
             Tupolev TB-3 Mikulin M-17

Specifications (BMW VI)

Side view of the BMW VI

General characteristics (82)

             Type: V-12
             Bore: 160 mm (6.30 in)
             Stroke: 190 mm (7.48 in)/199 mm (7.83 in) different between right and left cylinder bank due to articulated connecting rods.
             Displacement: 46.93 L (2,864 cu in)
             Length: 1,810 mm (71.26 in)
             Width: 859 mm (33.82 in)
             Height: 1,103 mm (43.43 in)
             Dry weight: 510 kg (1,124 lb)


             Fuel system: 2 x Zenith 60 DCL
             Fuel type: min. 87 octane gasoline
             Cooling system: Liquid-cooled


             Power output: 480 kW (650 hp)
             Compression ratio: 5.50