Jumo-213A for Dora - Page 15 - ED Forums
 


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Old 03-09-2015, 10:10 AM   #141
Kurfürst
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Quick and dirty of course and I am missing the boosted output of the BMW 801 here (2100 PS at SL IIRC), whereas the Jumo curve is for full boost, with MW -50. The normal output was around 1770 PS.

At lower altitudes there is some advantage of the 213 of course, largely due to its more efficient supercharger handling (no see-saw curve), which should show itself between 2-4 km range mostly... However it is seen that actually above rated altitude, ie. 6000+ m for both engines, the two engines are almost perform the same, despite the common myth that the Jumo 213 somehow improved the poor altitude performance of the BMW 801D. It simply didn't, where it improved over it was the much smaller cross setion and smaller drag of the engine installation. So at least at higher altitude practically all of the performance increase is due to the lower drag of the D-9 compared to the A airframe IMO.

EDIT: Added a rough estimate of C-3 injection boosted BMW 801 power levels
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Last edited by Kurfürst; 03-09-2015 at 10:16 AM.
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Old 05-01-2016, 05:14 PM   #142
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Quote:
Originally Posted by Nate--IRL-- View Post
I love this stuff, don't understand much of it, but I love it.

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Learn to understand it, and you'll love it more

These engines have a supercharger, a device that compresses the outside environment's air to above normal atmospheric pressure, so more air fits into each cylinder, so more fuel can be burned, increasing horsepower.

These graphs show:

-Engine power produced for a given air intake ('boost') pressure, and how this power output decreases as altitude increases (because the atmospheric air pressure decreases as you go higher, and the supercharger eventually loses its ability to compensate for that at higher altitudes.)

-Specific fuel consumption, which is the amount of fuel burned per hour, per horsepower produced. The higher the HP output, the dis-proportionally worse the 'gas mileage', but the better the acceleration, climb, & top speed. The airplane's range is shortened at higher power levels.

These 'ancient' WW2 piston engines (from all countries involved) were *incredibly* well understood and very highly developed for their time. People that tinker with cars today that have turbos, superchargers, 4-valve heads, etc. etc. and think they have something "high tech" are playing with 70 year old technology

In the 1930s and 40s, the P-51 was today's F-18, the Bf-109 was an F-16, and the Fw-190D-9 was an F-22
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Old 05-02-2016, 09:51 AM   #143
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Quote:
Originally Posted by Kurfürst View Post
Quick and dirty of course and I am missing the boosted output of the BMW 801 here (2100 PS at SL IIRC), whereas the Jumo curve is for full boost, with MW -50. The normal output was around 1770 PS.

At lower altitudes there is some advantage of the 213 of course, largely due to its more efficient supercharger handling (no see-saw curve), which should show itself between 2-4 km range mostly... However it is seen that actually above rated altitude, ie. 6000+ m for both engines, the two engines are almost perform the same, despite the common myth that the Jumo 213 somehow improved the poor altitude performance of the BMW 801D. It simply didn't, where it improved over it was the much smaller cross setion and smaller drag of the engine installation. So at least at higher altitude practically all of the performance increase is due to the lower drag of the D-9 compared to the A airframe IMO.

EDIT: Added a rough estimate of C-3 injection boosted BMW 801 power levels
I'm curious as to how the C-3 injection worked. As I understand it the 801 already ran on C-3 fuel, so the only reason I can think of for injecting more of it would be that the engine is capable of burning more fuel than the original injection system could provide. Obviously the additional fuel would also carry some charge cooling effect, but that is useless if you end up making the mixture so rich that the engine loses power.

Am I on the right track here?
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Old 05-02-2016, 10:44 AM   #144
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Nerd right track C3 Fuel was injected in the supercharger the spray cool down the intake air with that engine can run more rich and produce more power.
MW50 had on the 801 Radial engine much impact in reduce life span, and the more Power output was marginal.
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