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At any rate, here is what Germans thought about the 109F-4 and Fw 190A-2:
a) Geschwindigkeit:
Die FW 190 A 2 ist nicht ganz so schnell wie die Bf 109 F 4. Sie ist
aber einsätzmässig betrachtet, praktisch als gleich schnell zu werten.
Die Unterlegenheit der FW ist in grosser Höhe merkbarer und beträgt etwa
15 bis 20 km/h, während sie zwischen 4000 und 4500 praktisch gleich
schnell ist. Am Boden ist sie gleich schnell, oder sogar etwa 10 km
schneller.
(table)
Bei Notleistung ergibt sich dasselbe Bild.
Or:
a) Speed:
The Fw 190 A 2 is not as fast as the Bf 109 F 4. It is, however, service-capable (machine), in aggregate almost as fast. Lack of speed of the Fw is notable at higher altitudes, where it amounts to 15 to 20 km/h, while between 4000 and 4500 [m] is practically as fast. At sea level it is as fast, if not 10 km/h faster.
(table)
When using Emergency power setting, the same thing happens.
(quick & dirty translation by yours truly; German transcript from here, facsimile of the original doc here; the Fw was outfitted with 2 MGs + 2 cannons during the test)
We can take a look on how fast the Fw 190A-2 was by looking here. The non-polished A-2, also no outer cannons, doing 630-640 km/h already on Kampfleistung, and 660 km/h on Notleistung.
109G-6 top speeds are almost always quoted as 389mph, which seems to be right in the ballpark with the F-4. Were they really equivalent?
I always assumed that the G-6 was capable of more speed, especially when equipped with the AS engine.
Another example is Japanese aircraft always list low top speeds, while post war tests show the Ki-84 outrunning a P-51 at 20000ft.
And certainly the Ki-100 must have been capable of more than 360mph?
...
Here's what he found from German testing of the Bf 109 F-4:
Bf 109F-4 PERFORMANCE December 1941
Information for this model is also from Bruf=No. 509.
The Speed graph figures are estimated:
Altitude.Speed
Meters...mph
S.L......311
.1,000...322
.2,000...334
.3,000...346
.4,000...358
.5,000...369
.6,000...381
.7,000...388
.8,000...386
.9,000...374
10,000...367
Full throttle height: 390mph./6,700m. (21,982ft.)
Range (maximum): 994 mph./254 mph./182 gallons of fuel. (maximum internal fuel: 102 gallons)
Like my own findings, I don't see 400 mph anywhere. I have seen it mentioned along with a blurb about clearing the engine for more power, but nothing else was said about that. If the engine WAS cleared for more power, what was the ata cleared and date? Does anyone have German flight test for the Bf 109F after the engine was cleared for more manifold pressure?
I am absolutely willing to believe it could do 400 mph in level flight. I'm just looking for the flight test data at this point.
Another doc where we can read the Vmax = 670 km/h figure for the F-4 is here. Rated alttude is listed as H = 6.3 km, power used Nvmax = 1290 PS (= Notleistung) . Compared with 635 km/h at 6 km, using 1185 PS (= Kamp, as noted by the another doc.
WTS Koblenz is a military-history museum/institute. Wiki page: link.
The documents I quoted above are also available to anyone. They just don't agree. That's why I'm trying to figure out what is correct.
Hello
I don't know why we should have more faith in calculations of Messerschmitt AG than Milch, who often openly questioned them and sometimes ordered Focke-Wulf AG to check them. Also why would F-4 be 20 km/h faster than G-2, which was aerodynamically very similar even if somewhat heavier but had more powerful engine with higher FTH?
Juha
The documents I quoted above are also available to anyone. They just don't agree. That's why I'm trying to figure out what is correct.
It isn't a yes or no answer, or all that simple.
I believe that American or British tests were reported fairly. If they differ significantly from one another, then there is a good reason, which the researcher must try to find. The reason is always there, but it isn't always recorded.
I started looking at WWII fighters in the 1950s. I have books that were published back then. The Bf 109F variant wasn't shown as that fast until the late 1970s mid-1980s, and the references were always vague, just reported as a speed. It would appear to me that the widely-reported lower numbers were for the original tests that were, in fact, in the 385 mph range.
It appears now that, at some date, more manifold pressure was approved for the DB, just as it was for U.S. and British engines. The faster numbers would appear, on the surface, to be the results of that higher manifold pressure. But they don't exactly agree. I've seen 410 mph and 416 mph. In my mind, the difference between 410 mph and 416 mph is within individual airframe differences, and I'm willing to let that slide.
It seems like the Bf 109F was slightly above 400 mph in level flight after the increase in manifold pressure. We don't seem to know when that happened, or even if it really did. So far, it's a claim, and I haven't seen documents that say whether they are calculated or flight test data; just data tabulations. I'm open to the increase in speed, but want to know when it happened IN THE FIELD, and still want to see flight test data confirming it, with dates and test conditions. The purpose in that is to confirm that the aircraft tested was a production Bf 109F and not a test mule, as the Germans were very fond of at the time.
They passed off the He 100D as a production aircraft, and told the world that Me 209R was a standard fighter, too. So, my trust in the data isn't as doubtful as whether or not the aircraft tested was a production model. I have little doubt they tested something at that speed, but whether or not it was a combat-ready Bf 109F I can't say. At least in the U.S.A and the UK, you can find flight tests where a service aircraft was requisitioned and tested as it came from the unit, after being serviced.
Like I said above, it's worth looking into. Meanwhile, the performance numbers I believe are the ones published for 25+ years after the war, before someone dug up a memo talking about possible manifold pressure increases that still haven't been verified as used in the field at some time.
Hello Tomo
Finnish performance test for Bf 109 G-2 produced 523 km/h at sea level and 652 km/h at the FTH without the compressibility correction but 522 km/h and 636 km/h with it. I don't believe that it is a mere chance that the speeds without the compressibility correction are exactly same as the speeds Germans got for a Bf 109 G-2/R2.
But did the British make compressibility correction to their figures?
Juha
I might agree except I have no preconceived opinions and believe thew Bf 109 to be much better, in general, than it is credited for. I'm just looking for something that tells me the airframe is standard and the data is believable for a production aircraft. I have no notion it is WRONG.