Hi Tomo,
Agreed, the absolute values aren't that important actually.
Well, the original data was only computed anyway, based on tests that were conducted with real-life engine whose altitude performance, due to production variance, you couldn't actually establish with great accuracy. Few engines used for performance tests were even bench-tested for performance, and calculating altitude performance from bench-test performance was difficult too. So the drag table data, while original, is not necessarily more accurate or more useful than data we can compute for ourselves.
You're right, but these have only been available online for 15 years or so 
The Jumo 213A graph certainly was very welcome when first published! I've been using these values for my own calculations, so these should not be the reason for the difference between the drag table and my calculated values. However, such power curves were frequently revised, so the drag table data might have been based on a different revision.
In more general terms, such curves are really rare though - I've not seen similar gaphs for engines from other countries than Germany, though a few Merlin data points are provided by Hooker's "Performance of the Supercharged Aero-Engine". And even for German engines, power graphs showing only shaft power, but not exhaust thrust, are the rule rather than the exception.
Yes, and he has chosen some nice round values for making a textbook example to teach the analysis method, I don't think it was even meant to be accurate (though it certainly is realistic). He probably also meant to impress on his pupils the value of meticulous attention to aerodynamic detail.
Regards,
Henning (HoHun)
