Junkers Jumo 210

The Jumo 210 was Junkers Motoren's first production gasoline aircraft engine, produced just before the start of World War II. Depending on version it produced between 610 and 700 PS and can be considered a counterpart of the Rolls-Royce Kestrel in many ways. Although originally intended to be used in almost all pre-war designs, rapid progress in aircraft design quickly relegated it to the small end of the power scale by the late 1930s'. Almost all aircraft designs switched to the much larger Daimler-Benz DB 600, so the 210 was produced only for a short time before Junkers responded with a larger engine of their own, the Junkers Jumo 211.

Development of the Jumo 210 started in 1931 under the designation L10. The L10 was Germany's first truly modern engine design, featuring three valves per cylinder, an inverted-V layout, a supercharger as standard equipment, and a cast cylinder block. The 210 was odd in that the cylinders were machined into a block along with one side of the crankcase, two such parts being bolted together side-by-side to form the engine. Normal construction techniques used three parts, two cylinder blocks and a separate crankcase.

The L10 was first ran in static tests on October, 22nd 1932. With the official formation of the RLM in 1933, engine naming was rationalized with Junkers receiving the "200 block", the L10 becoming the 210. Type approval was achieved in March 1934, and it first flew on July 5th 1934 installed in a Junkers W33. The design had initially aimed for 700 PS, but the prototypes delivered only about 600 PS, so there was some disappointment in the industry. Nevertheless almost all German aircraft designs of the era were based on the 210, which is why they were so small compared to other country's efforts.

Initial production of the 610 PS (602 hp, 449 kW) Jumo 210A started in late 1934. Further development led in 1935 to the 640 PS (631 hp, 471 kW) 210B and 210C. Both added a new supercharger for improved performance, along with a waste gate to avoid overboost. The B model had its propeller geared at 1:1.55 (prop:engine rpm) for high-speed use, while the C model was geared at 1:1.63 for slower flying speeds. In 1936 the new 670 PS (661 hp, 493 kW) 210 D and 210E were introduced, which had the same gearing as the B/C but used a new two-speed supercharger to increase takeoff power and altitude performance.

The Jumo 210G was the world's first engine with direct fuel injection, developed by Dr. Lichte. The Jumo system used a small pump piston positioned beside each of the main cylinders, driven off the crank shaft. The injector used a simple check valve to prevent internal pressure from blowing back into the fuel line, and the pump was timed to inject at the proper point in the intake cycle. Inclusion of the injection system increased takeoff performance by about 20 PS without increasing boost rates and it also reduced fuel consumption. For those reasons most newer German engine types were set up with fuel injection systems. The Jumo 210G was rated at 700 PS (690 hp, 515 kW) and was only available for fast aircraft like the Bf 109 or Bf 110 but not for slow aircraft like the Ju 87.

Further developments were planned as Jumo 210F and 210H, but never built. In 1935 the Jumo 210H was used for development of the Jumo 211. A Jumo 210S was a special development by the DVL with special regulation mechanisms. Production of the Jumo 210 came to an end in about 1938.

pecifications (Jumo 210)

pistonspecs

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type=Twelve-cylinder supercharged liquid-cooled inverted V aircraft engine
bore=124 mm (4.88 in)
stroke=136 mm (5.35 in)
displacement=19.7 l (1,202 in³)
length=1,478 mm (58.19 in)
diameter=
width=686 mm (27.01 in)
height=960 mm (37.8 in)
weight=442 kg (974 lb)
valvetrain=Overhead camshaft
supercharger=Two-speed centrifugal type supercharger with automatic boost control
turbocharger=
fuelsystem=Carburetor
fueltype=87 octane rating gasoline
oilsystem=
coolingsystem=Liquid-cooled, ethylene glycol
power=
* 508 kW (690 PS or 681 hp) at 2,700 rpm for takeoff
* 515 kW (700 PS or 690 hp) at 2,700 rpm at 1,500 m (4,920 ft), first supercharger speed
* 501 kW (680 PS or 671 hp) at 2,700 rpm at 3,700 m (12,140 ft), second supercharger speed
specpower=26.14 kW/l (0.57 hp/in³)
compression=6.5:1
fuelcon=
specfuelcon=322-335 g/(kW•h) (0.53-0.55 lb/(hp•h))
oilcon=
power/weight=1.17 kW/kg (0.71 hp/lb)
reduction_gear=Spur, 1.75:1 or 1.59:1

Applications

*Arado Ar 68 - only in Ar 98E
*Focke-Wulf Fw 187
*Heinkel He 112
*Junkers Ju 87 - only in Ju 87A
*Messerschmitt Bf 109 - only in Bf 109 A-D
*Messerschmitt Bf 110 - only in Bf 110 A/B
*Messerschmitt Me 262 - Only in first test flight

References

*"A History of Aircraft Piston Engines", Herschel Smith

External links

*http://www.junkers.de.vu
*http://www.geocities.com/hjunkers/ju_jumo210_a1.htm