[Kurfürst]

Originally Posted by JtD

I don't think it is questionable if aircraft's condition is representative enough for a standard 109E. I'd say it is close enough, there are always differences between individual aircraft, even if all of them are brought up to the same specs. Weight is pretty much irrelevant at high speed, and drag from wing installed weapons was shown to be small. I also think the methods employed are sound, and the data is as solid as test data can be.

So far so good, but for me there are other open questions, mostly regarding high altitude performance.

I agree.

It was brought up in another topic - a plane going 500 at SL should manage a lot more than 575 at 5000m, if it has slightly more power available at altitude. Doesn't make sense the way it is.

Why? How about +12 Spitfires...? They seem to be claimed to go Thing is, the 601Aa doesn't have more power at altitude, it's pretty much the same at all altitudes.

Here's another take on it. If you look at Spitfire I speeds, roughly 285 mph at SL and about 355 mph at FTH, and the Merlin III's output, you will see that the Merlin has a good deal less power at SL than the DB 601A/Aa (about 870 HP vs 1045 PS).

At rated altitude, the Merlin offers a bit more power, but the two aircraft reach about the same top speed. In short, the 109E needs less power at altitude, which quite clearly points to less overall drag in the high speed regime.

So how on Earth would be it be slower or just as fast than Spitfire with more power (100-150 PS more) near SL...?

[/QUOTE] Also, V15 having a DB601Aa engine, the full throttle altitude of 4900m is unreasonably high, no answer found as of yet.[/QUOTE]

I don't think it's very unreasonable, 1000-1200 m gain in FTH due to high speed rammed power seems fairly typical, and it's seems it is what in all tests agree.

Spitfire tests do not show this kind of problems, which makes it easier for me to accept their results. They are more plausible. OTOH, Spitfire test results usually get less corrections and would therefore be less accurate.

Because we have so few Spitfire I tests.