Which was more valuable: mass production of the Jumo 213 in 1942 or Jumo 222 in 1943?

[davebender]

If aircraft specifications were written in 1937 then that's when engine factory expansion should have been funded. Plenty of time for factory completion by 1940.

 

[davebender]

Nothing unless you build an engine factory to produce it. So why not just build a larger factory for BMW132 or Bramo 323 engine?

 

[DonL]

Oh yes?

The germans produced 21000 BMW 132 and 5500 Bramo 323 between 1933-1945.
That are more produced BMW 132 then DB 601 (without DB 605).
And to my opinion the Wright R-1820 Cyclone was more advantaged and has more potential of development.

 

[Shortround6]

The 1525hp Cyclones were post war, required 115/145 fuel and had almost NO parts interchangeably with the 1200-1350 hp engines used in the B-17s. The Cyclone 9 was one of the longest lived but most modified engines in aviation history. The 1425-1525hp engines used 20 hold down studs per cylinder vs the 16 used on the 1000-1350 hp models and the earliest Cyclone 9s used only 12 studs for example.
Earliest Cyclone 9s were R-1750 of 525 hp at 1900rpm and weighed 760lb. the 1525hp model went 1469lbs and ran at 2800rpm. The 900-1000hp "G" series that became available in 1935 weighed 1198lbs (with reduction gear) and ran at 2200rpm (engine used in Finnish Brewster Buffaloes).

The R-1820 only has about 7.7% more displacement than the R-1690.

It rather depends on exactly which year/version the Germans could have gotten a license for. I believe the Soviets started with the 1932 "F" series engine. The Soviets did develop rather comparable engines to Wright up to about 1100hp (limited by fuel?) and I have no doubt the Germans could have matched that or exceeded it by a a margin but without using C3 fuel (or MW50) I doubt they would have gotten to 1200hp.

 

[DonL]

@ SR6

Do you think it would be possible for BMW to bring a german Wright R-1820 Cyclone to 1350PS, if we look what they have done with the BMW 132/ Pratt Whitney R-1690?

Edit:

Yes the Soviets got the Wright R-1820-F3.
I thought because the german did major progress with BMW 132 compare to the Pratt Whitney R-1690 with new pouring technics and much better and smoother cooling fins (1935) for a much better cooling, they can do equal things to the Wright R-1820 Cyclone. Also I think he would get a direct fuel injection.

 

[davebender]

RM 12,400. 960 PS BMW132J engine.
RM 27,970. 1,175 PS DB601A engine.

BMW801 engine had more potential too. That's beside the point. BMW132 engine was dirt cheap to mass produce and it's perfectly adequate for a late 1930s twin engine CAS aircraft. No need to negotiate a license agreement, spend time converting an entirely new engine design from American to metric measurements and designing new machine tools. Just expand existing BMW132 engine production to power the new CAS aircraft.

 

[Shortround6]

It doesn't seem likely.

The 1350HP engines were the "H" series engines which used Forged steel crankcases (introduced on the G-100 series of 1937 and modified twice), forged aluminium heads instead of cast with cooling fins machined in by ganged slitting saws, the sheet metal cooling fins rolled into groves in the cylinder barrels and other improvements. Take off power was 1350hp at 2700rpm (3093fpm piston speed) using 100/130 fuel and 9lbs boost (1.61 ata?).

Not only were the engines heavily modified but they were manufactured using different tooling and procedures than the earlier engines.
Based on displacement alone a R-1690 should have been able to hit 1253hp IF it could match the R-1820.

The R-1690 and R-1820 used the exact same bore, difference was in the stroke. 0.5in (12.7mm) so BMW might have been able to redesign to a larger displacement if they really wanted to. But the big limits on radials is getting enough cooling fins on the cylinder and using enough main and rod bearing.

 

[Shortround6]

BMW132 engine was dirt cheap to mass produce and it's perfectly adequate for a late 1930s twin engine CAS aircraft. No need to negotiate a license agreement, spend time converting an entirely new engine design from American to metric measurements and designing new machine tools. Just expand existing BMW132 engine production to power the new CAS aircraft.

enough with the "dirt cheap". It cost what it cost. It was a 9 cylinder radial that required certain steels and alloys and certain amount of machine time.

In 1937-39 a plane with a pair of 900-1100 hp engines was a medium bomber in most air forces, or a fast light bomber. Using a pair of medium bomber engines on a dedicated CAS plane was something Germany could not afford. And it doesn't matter if you are building 715hp 132a's or 947hp 132J's, aside from carburetor or fuel injection you have the same number of parts needing the same amount of machining and finishing for the same actual cost in any given year. Building the 715hp (or lower) powered versions in 1939-40 is truly a waste of time/resources.

 

[wiking85]

The next question then is what could the German aero-engine companies have achieved with better focus in their piston engine development?
If Daimler focuses only on the DB601/5 and 603, Jumo on the 205, 211/13, and 222, while BMW focuses on the 132/323 and 801. All else pretty much is not started or put off. Obviously jet engine are another category that doesn't fall into this breakdown.