Jumo-213A for Dora

[Yo-Yo]

As I wrote before, Jumo-213 engine is not simple and is not similar to the Merlin that became well aquainted during previous work. And as the basic model is rasping in the project code to the desired form of Jumo-213, it's possible to show the results got in vitro - in the special tool allowing full and fast multi-dimensional investigation of engine parameters and its tuning.

Reference points for power were taken from Motoren-Handbuch, Dec 1943, but as the fuel consumption key figures in this manual are for original MBG schedule that did not allow power ratings higher than Start - u. Notleistung (3250 rpm and 1.53 ata at SL), the schedule was taken from Ueberholungs - Anleitung, Oct 1944 for increased fuel flow scheduling, and reference point for specific consumption were calculated combining data for two sources.

 

The second diagram is very distinctive for the Jumo-213 (Motoren-Handbuch, Dec 1943). Manifold pressure vs ambient temperature at sea level dependance shows that constant air mass flow automatics keeping almost constant power vs altitude changing tries to keep constant power vs temperature changing but with less success, though.

Two parallel lines shows tolerance limits for the dependance from manual, and the blue line is the model response.

 

I emphasize that the diagrams show the model response to the ambient air condition. The live model uses fundamental parameters for the engine producing its performance as a result of complicated calculations.

 

So, as some of these parameters are unknown (MBG cams shape, for example, or exact blower chrachteristics) I need to adjust them for the overall performance or calculate, so overall set of obtained characteristics is a result of harmonisation and compromises... :)

Anyway, all curves have their distinctive shapes.

My special thanks to MACADEMIC for the priceless sources translation from German!

Edited September 18, 2013 by Yo-Yo

[Pman]

Really interesting Yo-Yo, I love the level of detail that you go into with your work :)

 

Be Proud

 

Pman

[Nate--IRL--]

I love this stuff, don't understand much of it, but I love it.

 

Nate

[NineLine]

Gah, I want to fly her already :)

[Yo-Yo]

I love this stuff, don't understand much of it, but I love it.

 

Nate

 

Is it due to my English? :)

 

And sorry: I did not mention that MBG is Engine Conrol Unit - a hydromechanical computer :) allowing to control prop and engine using only one lever.

Edited September 18, 2013 by Yo-Yo

[Paradox]

We're so lucky to have you and people like you Yo-Yo. Keep up the great work.

[hegykc]

Haha, the wolf pack was starving, about to turn on themselves.

 

So they threw us a bone.

 

Alright, we'll chew on that for a couple of days :)

[Para_Bellum]

Impressive.

[159th_Viper]

Is it due to my English? :)

 

No, definitely not. It's your intellect - you are simply too clever and me for one struggles to keep up with the technical aspects :)

[Pman]

No, definitely not. It's your intellect - you are simply too clever and me for one struggles to keep up with the technical aspects :)

 

Funny I said almost the same thing to him last time I met him!

 

Those Diagrams you drew at the time Yo-yo still baffle me lol

[Hans-Joachim Marseille]

Haha, the wolf pack was starving, about to turn on themselves. So they threw us a bone. Alright, we'll chew on that for a couple of days :)

(^.-)

 

Nice job Yo-yo ... I love looking at graphs. 2100 hp with supercharger & MW50 at take off ... So there won't be MW50?

Edited September 18, 2013 by Hans-Joachim Marseille

[Yo-Yo]

(^.-)

 

Nice job Yo-yo ... I love looking at graphs. 2100 hp with supercharger & MW50 at take off ... So there won't be MW50?

 

Yes, it's ready for MW-50 and 2100 hp.

[NineLine]

Yes, it's ready for MW-50 and 2100 hp.

 

Excellent... better to reach those B-17s :)

[Hans-Joachim Marseille]

Yes, it's ready for MW-50 and 2100 hp.

Yay! (^.^)b

 

"By preoccupations with a saving in gasoline on version A, the compressor engaged automatically only between 2700 and 3000 meters of altitude;

an interlocking with the request was nevertheless possible by the pilot with lower altitudes".

 

So that jump in manifold pressure and horsepower between 2700-3000 mtr. altitude is the compressor automatically kicking in.

Is it possible to let it kick in earlier manually to get a more fluid hp graph? Otherwise, I'll be avoiding the 3000 meter dogfights (compressor engaging/disengaging).

Edited September 18, 2013 by Hans-Joachim Marseille

[whatnot]

Haha, the wolf pack was starving, about to turn on themselves.

 

So they threw us a bone.

 

My thoughts exactly! :megalol:

 

Anyway, it did the trick and continue to be impressed about the level of depth that go into engine design alone!

[Yo-Yo]

Yay! (^.^)b

 

"By preoccupations with a saving in gasoline on version A, the compressor engaged automatically only between 2700 and 3000 meters of altitude;

an interlocking with the request was nevertheless possible by the pilot with lower altitudes".

 

So that jump in manifold pressure and horsepower between 2700-3000 mtr. altitude is the compressor automatically kicking in.

Is it possible to let it kick in earlier manually to get a more fluid hp graph? Otherwise, I'll be avoiding the 3000 meter dogfights (compressor engaging/disengaging).

 

MBG has the means to manually switch blower gear. But the effect is not so positive as you wait. THe "jump" in hp is not a jump. It's a power decreasing after 2.5 km that is critical altitude or full throttle altitude. Automatics lets power decrease a little then shift the gear to high. Though MP jumps, the power stays almost the same at 3 km, because blower begins to consume more power to itself.

 

Thus, shifting to HIGH is not wise at lower altitude because you will get less power. Coordinated control of rpm and MP (filling, to be accurate, or air mass flow) allows to have critical altitude near 2.5 km, so automatic switch gives the most even power curve.

Moreover, first version of MBG has means to vary shifting altitude regarding control lever position to make perfect fit, but later this feature was blocked and the shifting altitude remains constant.

[ATAG_Bliss]

Thanks for this.. I love how detailed these models are / will be. And the wolf pack has subsided for now :D

[Hans-Joachim Marseille]

MBG has the means to manually switch blower gear. But the effect is not so positive as you wait .... Moreover, first version of MBG has means to vary shifting altitude regarding control lever position to make perfect fit, but later this feature was blocked and the shifting altitude remains constant.

Thank you for the clear explanation Yo-Yo. It's quite a power loss (100 hp over 500 mtr. altitude) to let the compressor kick in so that the power graph will remain linear and not drop after 3000 mtr. altitude. Interested to see how this compares to the P-51D engine, although of course the flight model is a big contributor too (drag).

[SimFreak]

Nice post. Thanks for sharing this info.

[leafer]

No, definitely not. It's your intellect - you are simply too clever and me for one struggles to keep up with the technical aspects :)

 

Seriously, who wants to translate his post for us? :D

[MACADEMIC]

Good to see these graphs, and thank you for your kind words Yo-Yo. It is incredibly interesting and rewarding to work with you.

 

:book:

 

MAC

[Kodoss]

Jumo 213 A with 1770 PS against Jumo 213 J with 2250 PS

Left: PS; Below: height in km; Right: specific fuel consumption

 

From: Junkers Flugtriebwerke; Reinhard Müller; Aviativ Verlag

[Endy]

So if the FW190 is getting MW50 then does it mean P51D will get access to 150 Octane fuel? Afaik it is not currently modelled in DCS Mustang.

 

Sorry if that's not related to FW190, just jumping on the occassion to ask that question :)

[Mogster]

Its interesting to see the tech stuff behind the models, thanks for this.

 

Nice to see the 190D getting the MW50 :)

[upupandaway]

Nice read, thanks for sharing this. It´s always great to get these snippets from ED´s work process and I certainly enjoy to read (watch) it all.