Analysis of real life 109E performance for CloD

[IvanK]

Some more info.

I have a Russian (What I think) is an Engineering and Performance apprasial on the BF109E3 done in 1941. Its 117 pages and very detailed but being written in Cyrillic is hard going. Evident in the document the E3 has Auto Prop pitch.



Buried in the document for what its worth is this graph:



Looks like two sets of TAS v Altitude lines for different conditions and two sets of Time to height lines "t".

Be nice if a Russian speaker could repost the graph with the legends to the lines and the statement at the bottom in English.

[ZaltysZ]

This is level speed (TAS vs Altitude) and climbing (Climb time vs Altitude) chart. Units: m, km/h, min. I will look at this book later for translating the legends, because these are abbreviations in chart.

EDIT #1: curves with bubbles - "Manufacturer data", curves with crosses - "Data of Research institute (НИИ - Научно-исследовательский институт)"
EDIT #2: Tests were done at 2400RPM/1.35ATA. This is true for climbing test only until 5 minute mark, after which lower power setting was used.

[camber]

IvanK,

Nice document. That is clearly the full appraisal that goes with Test 7 (Russian captured E3) in the original thread post. The curve matches pretty much exactly.

The Russians clearly took the Messerchmitt guaranteed 109 performance seriously.. they have plotted it alongside. If I was shopping for a secondhand 109E for the local pylon races I think I would give that one a miss, it really seems a bit of a lemon.

Cheers, camber

[5./JG27.Farber]

In what conditions were all these aircraft captured? I remember reading somewhere the 109 needed a service after 10 flying hours.

[JG4_Helofly]

Is it still a discussion about correcting performance in the game or do we fight the real BOB again?
If it's still about the game, then I doubt that taking some perf. tests from captured aircrafts will get us very far. It's pointless to discuss about taking such data for the FM. Why? Simply because it would be impossible to estimate the average performance of several thousands of planes at a given time in a given battle. Especially when you don't have a representativ number of tests.
How can it be justified to change the top speed of the 109 based on a few testflights from foreign countrys?
And if we would go down that road, how about low production quality in late war scenarios? Or other factors who would affect performance?

IMO the only way to have acceptable performance data is to take the theoretical values which should be reached by production aircrafts under normal conditions. Everything else is just BS.

[camber]

Originally Posted by JG4_Helofly

Is it still a discussion about correcting performance in the game or do we fight the real BOB again?

Well actually neither, it was a discussion about whether the actual 109E performance possibly deviated from (or within) the Messerchmitt specs, based on German and captured aircraft tests. Of course then there is a further argument about whether it would be best for which data to be in CloD. Currently the sea level 109 is too slow for either side of the argument.

Originally Posted by JG4_Helofly

If it's still about the game, then I doubt that taking some perf. tests from captured aircrafts will get us very far. It's pointless to discuss about taking such data for the FM. Why? Simply because it would be impossible to estimate the average performance of several thousands of planes at a given time in a given battle. Especially when you don't have a representativ number of tests.

I disagree. It is never pointless to examine actual flight tests provided their limitations are considered...but you are correct captured aircraft tests should be treated with extra suspicion, as in the original post.

Originally Posted by JG4_Helofly

How can it be justified to change the top speed of the 109 based on a few testflights from foreign countrys?
And if we would go down that road, how about low production quality in late war scenarios? Or other factors who would affect performance?

IMO the only way to have acceptable performance data is to take the theoretical values which should be reached by production aircrafts under normal conditions. Everything else is just BS.

That is a valid position for argument. However I do not think that means alternative arguments are BS. I would also say the Messershmitt specs are +/- 25 kmh at sea level, even adjustments within these bounds may change your online experience with such closely matched aircraft as Spits and 109s.

camber

[JG4_Helofly]

@ Camber. I understand that you want the game to be as close as possible to RL. But we don't have the data to do this. If you had several thousands of test data from production aircrafts, then it would be representativ. Since we don't have this amount of data everyone can pick one of the tests and say: "but plane X was 25 km/h slower in this test". People who like plane X will say: "But it was 25km/h faster in an other test".
And there will be arguments about production quality, fuel availability, maintenance problems etc.
And that's exactly what we have now. That's why we need a solid base. Data we can agree on. That's why the only realistic approache is to model the planes according to standard specifications and taking all other variables out of the equation. Otherwise we will continue to argue about every km/h and everyone will pull out the test result which fits the agenda.

IMO the only alternative would be to have a performance spread of +/- 5% for every plane. So every plane would have it's standard performance values it should reach, but you could get a plane with a few % worse or better performance.

I really don't see how you could do it otherwise without having arbitrary performance values.

[5./JG27.Farber]

How much fuel was in the aircraft during any of these tests? That could be another factor that affects top speed. What if the German tests were with half a tank of Benzine and the Russian/UK/USA tests were with of full tank of there own grade of fuel? This would be a big difference. around 200kilos or 440lbs... Also is the aircraft clean and trimmed properly? Is the airframe bent from battle damage or crash landing?