Powerplants
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.
Variants
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)
|
1,000
|
986
|
736
|
2,200
|
|
A (late)
|
1,100
|
1,085
|
809
|
2,300
|
|
B,C,D,H,G
|
1,200
|
1,184
|
883
|
2,400
|
|
F,L,M,R
|
1,340
|
1,322
|
986
|
2,600
|
|
J
|
1,420
|
1,401
|
1,044
|
2,600
|
|
N
|
1,450
|
1,430
|
1,067
|
2,700
|
|
P
|
1,500
|
1,479
|
1,103
|
2,700
|
Applications
• 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)
Components
• 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
Performance
• 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.
Applications
• 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
• Schienenzeppelin
• 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)
Components
• Fuel system: 2 x Zenith 60 DCL
• Fuel type: min. 87 octane gasoline
• Cooling system: Liquid-cooled
Performance
• Power output: 480 kW (650 hp)
• Compression ratio: 5.50
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