Junkers Jumo 205

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Diesel opposed piston engine Junkers Jumo 205
Junkers Jumo 205, cutaway model

The Junkers Jumo 205 is one of the Junkers engine GmbH (from 1936: Junkers ) developed and built six-cylinder two-stroke diesel - opposed piston engine . About 900 of the different versions were built.

development

When it became apparent that the Jumo 204 would no longer meet the increasing requirements, Junkers had been planning a successor model since 1931. It should deliver the same performance with reduced dimensions. At first, the new engine was called the Jumo 5. The first test run took place on December 1, 1932, and the type certification took place in the spring of 1933 . The first subsequent test of the engine took place in a Lufthansa Focke-Wulf A 17 .

In order to make the engine, known as Jumo 205 from 1934 , operationally reliable, many problems had to be solved in advance. For example, the pistons burned out initially and piston seizures were also common. To avoid this, the pistons were made of different metals, and heat protection hoods were screwed onto the piston crowns. In addition, each piston received an undivided piston ring at the top (the so-called fire ring) to ensure heat dissipation and gas tightness.

The engine had a good reputation with Deutsche Lufthansa ; it was strong, reliable, and fuel efficient. When used in combat aircraft , however, it showed unsatisfactory properties, so it reacted slowly to changes in speed and formation flight with its many control processes also caused many engine problems. Its preferred use was the long-haul flight in reconnaissance and patrol flights over sea. In cruise, the specific consumption was between 218 and 231 g / kWh, with record flights reaching 211 g / kWh. The Jumo 205 was used in the early version of the Junkers Ju 86 bomber and in the Dornier Do 18 and Blohm & Voss Ha 139 flying boats .

It was later developed into the Jumo-207 B-altitude engine , equipped with an exhaust gas turbocharger and charge air cooler . This engine was used in the Ju 86 P / R altitude reconnaissance aircraft.

Technical specifications

Junkers Jumo 205D
Parameter Data
Manufacturer    Junkers
Construction year    1940
design type    6-cylinder opposed piston engine, two-stroke, diesel
Displacement (bore × stroke)    16.62 L (105 mm × 160 mm × 2)
Charging    Rinsing fan
Dry matter    595 kg
Starting power kW (PS)    650 (880)
spec. Fuel consumption g / kWh (g / PSh)    231 (170)

Engine types

  • Jumo 5A, B, C

first series version, 405 kW (530 PS) at a speed of 2,100 / min, A, B, C different ratios of the propeller shaft

  • Jumo 205A, B, C

Variant, 440 kW (600 hp) at a speed of 2,200 rpm, glycol hot cooling, vibration damper on the crankshaft, renamed Jumo 205 in 1934

  • Jumo 205D

Air force version, 650 kW (880 PS) at a speed of 2,800 / min, improved flushing fan

  • Jumo 205E, G.

Version for Deutsche Lufthansa, 515 kW (700 PS) at a speed of 2,500 rpm, service life 1,000 hours

See also

Web links

Commons : Junkers Jumo 205  - Collection of pictures, videos and audio files

Individual evidence

  1. ^ Herbert Ringlstetter: Junkers Ju 86. Conservative modern. In: Flugzeug Classic No. 4/2020, p. 56.
  2. Kyrill von Gersdorff, Kurt Grasmann: Flugmotoren und Strahltriebwerke , Bernard & Graefe Verlag 1981, p. 90
  3. ^ Gersdorf / Grasmann / Schubert: Aircraft engines and jet engines. Bernard & Graefe Verlag, Bonn 1995, ISBN 3-7637-6107-1 , p. 91.