Deleted member 1487
I'm not sure that means pressurized, instead just the name of the liquid cooling system.Pg. 86 of 'Flugmotoren und strahltriebwerke' book, part of book dealing with Jumo 211 series:
"Die Bauereihen A bis H hatten eine geschlossene Druckkuehlanlage..."
that translated by Google translate means:
"The construction series A to H had a closed pressure cooling system..."
These sources say the Jumo 211 lacked such a system:
https://books.google.com/books?id=isMTDQAAQBAJ&pg=PT112&lpg=PT112&dq=jumo+211+cooling+system&source=bl&ots=hsYxkE5UHH&sig=ACfU3U2l9ZW9LQkXIHj9ymHvR1gBfzjSdA&hl=en&sa=X&ved=2ahUKEwiK09vazcDgAhXH7YMKHeEoB2AQ6AEwEnoECCMQAQ#v=onepage&q=jumo 211 cooling system&f=false
https://books.google.com/books?id=EqZio4ykVTUC&pg=PA48&lpg=PA48&dq=jumo+211+cooling+system&source=bl&ots=ysTeHhZEc5&sig=ACfU3U0PnfG9EsccvPf5zpmTJwaD9MDNPg&hl=en&sa=X&ved=2ahUKEwjx8bj2zsDgAhUD04MKHdoeD_wQ6AEwFHoECCEQAQ#v=onepage&q=jumo 211 cooling system&f=false
https://en.wikipedia.org/wiki/Junkers_Jumo_213
When the Jumo 211 entered production in the late 1930s it used an unpressurized liquid cooling system based on an "open cycle". Water was pumped through the engine to keep it cool, but the system operated at atmospheric pressure, or only slightly higher. Since the boiling point of water decreases with altitude (pressure) this meant that the temperature of the cooling water had to be kept quite low to avoid boiling at high altitudes, which in turn meant that the water removed less heat from the engine before flowing into the radiator to cool it.
By contrast, the 1940 Daimler-Benz DB 601E used a pressurized coolant system that ran at the same pressure regardless of altitude, raising the boiling point to about 110 °C. This allowed it to use considerably less water for the same cooling effect, which remained the same at all altitudes. Although otherwise similar to the Jumo 210 in most respects, the 601 was smaller and lighter than the 211, and could be run at higher power settings at higher altitudes, making it popular in fighter designs. The 211 was relegated to "secondary" roles in bombers and transports.
The Junkers Motorenwerke firm was not happy with this state of affairs, and started its own efforts to produce a pressurized cooling system as early as 1938. Experiments on the 211 proved so successful that it became clear that not only could the engine be built smaller and lighter (by reducing the water requirement),[2] but could be run at higher power settings without overheating. Additional changes to strengthen the crankshaft and add a fully shrouded supercharger for increased boost resulted in the Jumo 211F model, which delivered 1,340 PS (1,322 hp, 986 kW) at 2,600 RPM, up from 1000 PS at 2,200 RPM in the first version 211A.
The Jumo engines were listed as L1-L10 with the Jumo 210 being the renamed L10.Junkers L 88 engine, not Ju-88 aircraft, sorry for dropping the letter. Intercooler is mentioned at pg. 80 of 'Flugmotoren und strahltriebwerke' book.
'Jumo' (Junkers motors, roughly) got that name some time in mid/second half of 1930s.
https://en.wikipedia.org/wiki/Junkers_Jumo_210
The first gasoline-burning aviation power plants that the Junkers Motorenwerke ever built, the L1 and L2 single overhead camshaft (SOHC) liquid-cooled inline-six aviation engines of the early and mid-1920s. Development of this line led up through the L8. All of these were developments of the BMW IIIa inline-six SOHC German World War I aviation engine, which BMW allowed as they were no longer interested in development of their WWI designs. The Junkers L55 engine, however, was the very first V12 layout aviation powerplant of any type created by the Junkers firm, using a pair of the earlier straight-six L5 engines as a basis for an "upright" liquid-cooled V12 aviation engine, as the contemporary BMW VI engine already was.
Development of the Jumo 210 itself started in 1931 under the designation L10. The L10 was Germany's first truly modern engine design, featuring three valves per cylinder,[1] 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 22, 1932. With the official formation of the RLM in 1933, numerical engine designations by manufacturer 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 5, 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 countries' efforts.
The L88 appears to have been a different engine:
https://de.wikipedia.org/wiki/Junkers_Jumo_210
Just because the L88 had an intercooler doesn't mean the Ju210 or 211 did, as I can find no reference to the intercooler before the Jumo 211J.Then began in 1931 in Dessau , the Junkers engine GmbH under the direction of Otto Mader with the development of the Jumo 210. The new engine turned over its predecessor, the V-12 engine L 88 with vertical engine (crankshaft below) a generational leap because It was first designed by Junkers, taking into account the vibration behavior in the barrel. The predecessor was still trying to achieve a minimization of vibration by oversized components, but this led to a high weight with large moving masses . The through the optimized parts such as crankshaft, connecting rod , pistonetc. achieved weight reduction allowed much higher speeds, so that the Jumo 210 had only about half the power of the L 88.
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