Frozen_Lake
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- Apr 18, 2017
Does anyone have the power curves for the Jumo 211A engine?
Jumo 211A and 211B Data Needed
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Deleted member 68059
Staff Sergeant
- 1,058
- Dec 28, 2015
Yes, I do. However for those of us who have got such things at great expense of time and effort in various archives - it might be nice if you could include in your request what you want from it.
For example, you could have the original from the manual, that actually measured by the British, the Americans....etc....
Helpful if you explain what you are trying to achieve.
For example, you could have the original from the manual, that actually measured by the British, the Americans....etc....
Helpful if you explain what you are trying to achieve.
Perhaps these two links might be of interest, since the manuals contain data about power of Jumo 211A/A-1/A-2 engines:
Muzeum Lotnictwa Polskiego w Krakowie
http://www.muzeumlotnictwa.pl/index.php/digitalizacja/katalog/2268
No power curves, but can be reasonably accurate to draw them from the tabulated data.
Muzeum Lotnictwa Polskiego w Krakowie
http://www.muzeumlotnictwa.pl/index.php/digitalizacja/katalog/2268
No power curves, but can be reasonably accurate to draw them from the tabulated data.
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Frozen_Lake
Recruit
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- Apr 18, 2017
Thank you guys. I am trying to make a few calculations regarding the most economical "Reiselestung" (Cruising Power) and the longest sustainable "Dauerleistung" (Continuous Power) of an airplane, more specifically, the Ju-87 B-1. I hope I am correct in thinking that the Ju-87 B-1 was equipped with the Jumo 211A engine.
The specific data that I need is engine RPM, power, manifold pressure and fuel consumption at certain altitudes. And, ideally, speed that can be achieved at the above-mentioned two conditions, namely, most economical cruising power and longest sustainable continuous power.
The specific data that I need is engine RPM, power, manifold pressure and fuel consumption at certain altitudes. And, ideally, speed that can be achieved at the above-mentioned two conditions, namely, most economical cruising power and longest sustainable continuous power.
Deleted member 68059
Staff Sergeant
- 1,058
- Dec 28, 2015
I think nearly everything on the engine you want can be found on page 15 of the document that Tomo gave you links for - unfortunately I do not have aircraft manuals for the Ju87 of any variant, so could not tell you how that power might be translated into a particular speed.
The Imperial War Museum archive probably have a Ju87 manual, but you`ll have to physically go there, so unless you are in the UK thats not very useful for you I suppose.
I have detailed graphs of fuel consumption, ratings, permitted durations vs altitude, but only for the 211B onwards. For the 211A I only have power vs altitude, not fuel consumption data.
The Imperial War Museum archive probably have a Ju87 manual, but you`ll have to physically go there, so unless you are in the UK thats not very useful for you I suppose.
I have detailed graphs of fuel consumption, ratings, permitted durations vs altitude, but only for the 211B onwards. For the 211A I only have power vs altitude, not fuel consumption data.
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Frozen_Lake
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- Apr 18, 2017
Indeed, thank you very much. Page 15 contains manifold pressure, rpm, power and fuel consumption at ground level and at 4,500 m altitude.
I see power curves on page 33 too, thank you very much. And to my delight, the graph on that page displays the "Dauerleistung" curve at 2100 rpm and 1.05 ata. I assume this is the maximum sustainable continuous power of the Jumo 211A engine. The only thing that is left is the most economical "Reiseleistung" (Cruising Power) curve, or at least data at certain altitude (similar to page 15 of the quoted document), which I expect to be around 1600-1700 rpm. For example, the most economical cruising power of the Jumo 211B engine appears to be at 1700 rpm.
Yes, not very useful indeed, due to the fact that I am in Japan, halfway across the world from The Imperial War Museum. However, I would be interested in your power vs altitude data on the Jumo 211A engine, if you happen to have the above-mentioned most economical cruising power.
Last edited:
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Frozen_Lake
Recruit
- 6
- Apr 18, 2017
I would like to thank Tomo, Snowygrouch and Algernon for their help with the data that I am looking for. Unfortunately, I still haven't found all the data that I need but I am happy to say that I have made considerable progress toward that goal, thanks to the above-mentioned people.
During my research on some of the performance aspects of the Jumo 211A and 211B engines, I came across a number of problems that I need to solve in order to complete my calculations. The power curves of the Jumo 211A and Jumo 211B that I have found so far are these:
Jumo 211A: http://www.muzeumlotnictwa.pl/digitalizacja_archiwaliow/katalog/2285/18.jpg
Jumo 211B to Jumo 211H: https://ww2aircraft.net/forum/attachments/jumo-211-b-h-power-curves-pdf.65468/
These documents are very informative. However, I also need the following data on the Jumo 211A and/or Jumo 211B:
1. Air-fuel ratio
It may take the form of mass parts of air to mass parts of fuel (for example, 12.5:1, which would be a rather rich mixture), or λ (lambda) which is derived from the actual air-fuel ratio divided by the stoichiometric air-fuel ratio (which is when exactly enough air is provided to burn all the fuel, 14.7:1 in the case of gasoline). So, a rich mixture would have λ less than 1, and a lean mixture would have λ more than 1.
2. Brake Mean Effective Pressure Differential (BMEPd)
To clarify, the Brake Mean Effective Pressure Differential (BMEPd) is different from the Brake Mean Effective Pressure (BMEP). BMEP can be easily calculated given the Power (for example, from the Power Curves) and the Theoretical Volumetric Flow Rate (derived from engine displacement and RPM). However, the BMEPd is derived from the Measured (i.e., actual, not theoretical) Volumetric Flow Rate, and therefore is different from BMEP. Both are measured in units for pressure.
3. Volumetric efficiency (VE)
This is the ratio between the Measured Volumentric Flow Rate and the Theoretical Volumetric Flow Rate. The ratio is of course dimensionless, but the Flow Rate is measured in cubic feet per minute or cubic meters per second.
Any help will be highly appreciated.
During my research on some of the performance aspects of the Jumo 211A and 211B engines, I came across a number of problems that I need to solve in order to complete my calculations. The power curves of the Jumo 211A and Jumo 211B that I have found so far are these:
Jumo 211A: http://www.muzeumlotnictwa.pl/digitalizacja_archiwaliow/katalog/2285/18.jpg
Jumo 211B to Jumo 211H: https://ww2aircraft.net/forum/attachments/jumo-211-b-h-power-curves-pdf.65468/
These documents are very informative. However, I also need the following data on the Jumo 211A and/or Jumo 211B:
1. Air-fuel ratio
It may take the form of mass parts of air to mass parts of fuel (for example, 12.5:1, which would be a rather rich mixture), or λ (lambda) which is derived from the actual air-fuel ratio divided by the stoichiometric air-fuel ratio (which is when exactly enough air is provided to burn all the fuel, 14.7:1 in the case of gasoline). So, a rich mixture would have λ less than 1, and a lean mixture would have λ more than 1.
2. Brake Mean Effective Pressure Differential (BMEPd)
To clarify, the Brake Mean Effective Pressure Differential (BMEPd) is different from the Brake Mean Effective Pressure (BMEP). BMEP can be easily calculated given the Power (for example, from the Power Curves) and the Theoretical Volumetric Flow Rate (derived from engine displacement and RPM). However, the BMEPd is derived from the Measured (i.e., actual, not theoretical) Volumetric Flow Rate, and therefore is different from BMEP. Both are measured in units for pressure.
3. Volumetric efficiency (VE)
This is the ratio between the Measured Volumentric Flow Rate and the Theoretical Volumetric Flow Rate. The ratio is of course dimensionless, but the Flow Rate is measured in cubic feet per minute or cubic meters per second.
Any help will be highly appreciated.
Shortround6
Major General
I am not sure what you are trying to accomplish as you are getting into more theory than practical measurements.
While BMEP is easy to calculate it is not particularly accurate as to what is going on in the engine. Much more accurate (although still calculated and not measured) is IMEP (Indicated Mean Effective Pressure). IMEP includes the power needed to overcome internal friction, aircraft engine makers turned the engines over with electric motors at various rpm to measure friction and often added/subtracted components to measure JUST the friction in bearings or rings (detached the valve gear for example).
IMEP also includes the power needed to run the supercharger. This varies considerably between high and low gear. Again engineers can measure the power needed by using electric motors on test stands.
Adding these known (at least to company engineers) power requirements to the measured propshaft HP and then doing the calculations gets you the IMEP.
Please note that the Volumentric Flow Rate is going to change with altitude (pressure) and even at sea level based on the temperature and local air pressure. Engines actually making power based on pounds or kilograms of air flowed and not cubic ft or cubic meters. It is easier to measure/meter volume and not mass and as long as all comparisons are done the same way or corrected to the same standard it is no problem.
Trying to tie the theory back to actual aircraft performance (as in the JU-87 in flight) gets even trickier as often the pilot did not have absolute control over the mixture settings.
Article is for the Jumo 211D and may be a bit biased: rolls-royce merlin | 1941 | 0562 | Flight Archive
another with less theory is : petrol injection | injection system | detailed examination | 1940 | 0133 | Flight Archive
In the first please note that the Jumo as fitted to the He 111 was equipped with an automatic mixture control which used a lower limit somewhat richer than the "ideal" weak mixture.
While BMEP is easy to calculate it is not particularly accurate as to what is going on in the engine. Much more accurate (although still calculated and not measured) is IMEP (Indicated Mean Effective Pressure). IMEP includes the power needed to overcome internal friction, aircraft engine makers turned the engines over with electric motors at various rpm to measure friction and often added/subtracted components to measure JUST the friction in bearings or rings (detached the valve gear for example).
IMEP also includes the power needed to run the supercharger. This varies considerably between high and low gear. Again engineers can measure the power needed by using electric motors on test stands.
Adding these known (at least to company engineers) power requirements to the measured propshaft HP and then doing the calculations gets you the IMEP.
Please note that the Volumentric Flow Rate is going to change with altitude (pressure) and even at sea level based on the temperature and local air pressure. Engines actually making power based on pounds or kilograms of air flowed and not cubic ft or cubic meters. It is easier to measure/meter volume and not mass and as long as all comparisons are done the same way or corrected to the same standard it is no problem.
Trying to tie the theory back to actual aircraft performance (as in the JU-87 in flight) gets even trickier as often the pilot did not have absolute control over the mixture settings.
Article is for the Jumo 211D and may be a bit biased: rolls-royce merlin | 1941 | 0562 | Flight Archive
another with less theory is : petrol injection | injection system | detailed examination | 1940 | 0133 | Flight Archive
In the first please note that the Jumo as fitted to the He 111 was equipped with an automatic mixture control which used a lower limit somewhat richer than the "ideal" weak mixture.
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Frozen_Lake
Recruit
- 6
- Apr 18, 2017
Thank you very much for that information.
I will have to read both articles carefully but from first glance I think there is a small mistake in the description of the figures in the first article on this page:
royal aircraft | aircraft establishment | pressure rise | 1941 | 0564 | Flight Archive
It seems to me that Figure 1 shows the consumption loops of the Jumo 211D engine and Figure 2 shows the consumption loops of the Merlin X engine. Am I right?
I will have to read both articles carefully but from first glance I think there is a small mistake in the description of the figures in the first article on this page:
royal aircraft | aircraft establishment | pressure rise | 1941 | 0564 | Flight Archive
It seems to me that Figure 1 shows the consumption loops of the Jumo 211D engine and Figure 2 shows the consumption loops of the Merlin X engine. Am I right?
Shortround6
Major General
You could be, it would sure conform more to the descriptions in the text.
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Frozen_Lake
Recruit
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- Apr 18, 2017
How did they estimate the BMEP of the engines? Do you think they measured the torque with a dynamometer and then, using the formula below, calculated the BMEP in psi?
BMEP (psi) = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)
BMEP (psi) = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)
