Spit/109 sea level speed comparisons in 1.08 beta patch

[Kurfürst]

Originally Posted by Holtzauge

I would love too see those test results.

Seems to me like you are confusing the calculated speed of the V15 prototype at 1.35 ata

It takes a great deal of dishonesty and/or confusion to claim the V15a speeds are calculated.

"An Bf 109 V 15 a, der Mustermachine für die E-1-Serie, wurden die Geschwindigkeitsleistungen erflogen."

Can you translate the above please?

or the caveted Messerschmitt marketing material with actual test results.

Trouble is, Messerschmitt's type specification sheet ("marketing material") is the official specification for the aircraft, and was to be met by all similar Bf 109E in the Luftwaffe within +/- 5%.

The only test results I've seen point to 466-475 Km/h.

Well again it takes a great deal of dishonesty and/or confusion to claim not having seen flight test results, when the V15a flight tests have been posted in their full just a couple of pages back.

You still have not answered the question: How do you account for HoHun's estimate of 475 Km/h?

You should ask HoHun, but as you say: it's an estimate. For a different engine.

Curiously though, the French were hitting the exact same speeds at low levels (ca. 493 km/h) with their captured Bf 109E-3 as the Germans did with the E-1 (V15a)



It will be amusing when next time, you will claim you have not seen this either.

But, oh boy I forgot, you have your own charts.

Now let's see how speed figures claimed by British propaganda measured up to actual speed measurements... ooops, not very well it would seem! I am really looking forward to see a historically accurate Spitfire Mark V.

[Holtzauge]

I do read German and therefore I know the difference between what was flown and what was projected for the V15 prototype: "Blatt 6" shows about 485 Km/h for the FLOWN 1.3 ata value and the ESTMATED 500 Km/h value for "Geschwindigkeiten bei Garantierter Motorlesitung" 1.35 ata as a dashed line. So who is being dishonest now?

Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.

So HoHuns and my calculations are for "a different engine" and can be discounted as "estimates"?. Quite interesting that this method of calculation works well with the Spitfire and also mirrors 466-475 km/h Rechlin test results for the Me109E SERIES aircraft no?

I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?

[Al Schlageter]

Here is the document mentioned earlier.
http://www.kurfurst.org/Performance_...catter_web.jpg

13 a/c

4 below spec -5% > 31%
6 below mean > 46%
3 above mean > 23%

The average for all the a/c is well below the mean.

Applying this to the Bf109E would give an average speed of ~485kph.

[Kurfürst]

Originally Posted by Holtzauge

I do read German and therefore I know the difference between what was flown and what was projected for the V15 prototype: "Blatt 6" shows about 485 Km/h for the FLOWN 1.3 ata value and the ESTMATED 500 Km/h value for "Geschwindigkeiten bei Garantierter Motorlesitung" 1.35 ata as a dashed line. So who is being dishonest now?

That's not really a question, it is still you (and you are doing it rather poorly as usual), so continue translating, maybe you are better at that - its funny you have not translated the first part isn't it.

2. Stoppflug.

Ergebnis: Erflogene Geschwindigkeit 493 km/h, auf Normaltag und Garantieleistung umgerechnete Geschwindigkeit 498 km/h im 0 m. Umrechnung siehe Blatt 5.

For those who do not wish to bother much with Holtzeuge's incoherent lies, here's the deal (as noted by the report clearly):

The aircraft (V15a), identical in all to series production E-1 flew low altitude speed trials on a four way track. The engine was bench tested as well (actually the ONLY test I am aware was this through), as was found to develop 45 PS less, and developed only 1.31ata in fligth instead of 1.35. Calibration flights were also made.

The 'raw' data collected (493 km/h at 0 m) was then converted for standard conditions: German Standard day atmospheric conditions, and normal engine power. The result was 498 km/h at 0m. The methods are clearly visible at the end of the report.

This is of course entirely normal, almost all Spitfire etc. tests for example do the same thing: correct the figures to normal boost ratings, and adjust for (British) Standard Day conditions. Otherwise, they would be useless for comparison...

Holtzeuge claim is basically because the flight tested data was converted (as usual) to standard conditions it needs to be dismissed because it's an 'estimate.'

Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.

So HoHuns and my calculations are for "a different engine" and can be discounted as "estimates"?

Well they ARE estimates and they are for a different engine and different boost...

Quite interesting that this method of calculation works well with the Spitfire and also mirrors 466-475 km/h Rechlin test results for the Me109E SERIES aircraft no?

Nope, your calculations are not interesting at all.

I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?

Oh, not so finnicky about 'marketing brocheres' any longer, are we?

[ACE-OF-ACES]

Originally Posted by Holtzauge

I don't know about any book but the site as such contains some nice info and HoHun has posted a lot of interesting speed and climb analysis for a number of aircraft so the site is well worth a visit.

Ok, I just remembered butch2k's names from years ago.. He was a very informative and level heading logical guy from what I remember.. There was another guy with a name similar to his.. B something, maybe he was the guy writing the book?

Originally Posted by Holtzauge

To the best of my knowledge we use different ways to calculate performance but from what I have seen so far we seem to arrive at quite similar conclusions. My C++ simulation also allows incremental integration of data so I can model transient flight conditions like dive and zoom and instantaneous turn etc.

By the way your name rings a bell too.. I seem to recall seeing your C++ stuff a few years back.. Very neat stuff! I have some of Henning Rush's stuff posted at my website.. i.e. www.flightsimtesting.com and would love to post some of yours too! What format is your output files? Simple text I assume? Could I get a copy?

Originally Posted by Holtzauge

I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?

I see you have 'experience' with Kurfurst too!

[TomcatViP]

Originally Posted by Holtzauge

Actually it is. I'm going to use the C++ results in a book project so I'm not going to sink my own project by posting my code before that

Well... and naming the eq. that you use is that so much classified that you can't even do it?

[MiG-3U]

Originally Posted by Holtzauge

Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.

The French test shows about 494kmh at about 550m and and power chart gives about 1010ps at 550m, these values give 482kmh at sealevel with 990ps.

The outliers, like the sealevel speed in the V15a test, are usually caused by measurement errors. And given the fact that speeds match better with other tests at high altitude, it is probable that something is not right in the V15A measurements (error can be anything; failing device, typing error, calibration problem etc.).

[Kurfürst]

Originally Posted by MiG-3U

The facts:
1. Prototype aircraft V15a, tested well before production started
2. Tested speed 493kmh at altitude of 440m, gives 485kmh at 0m

Originally Posted by MiG-3U

The French test shows about 494kmh at about 550m and and power chart gives about 1010ps at 550m, these values give 482kmh at sealevel with 990ps.

Seems there's then good agreement between the German tests with the E-1 at 1.31ata and the French tests with the E-3 at 1.3 ata then even according to Harri's own estimates.

Of course it should be kept in mind that the final E-1 results were corrected to 1.35ata and Standard Day, and resulting in 498 km/h, and that our E-1/E-3/E-4 models have 1.35 ata.

The outliers, like the sealevel speed in the V15a test, are usually caused by measurement errors.

Good point. Since the two brief trials of 467-475 kph you mentioned fell well out of the official and other measured tests, and they note that some necessary corrections were not made (the first trial mentioning that the SL speeds were simply graphically extrapolated to SL, and both trials noting the figures are not yet corrected to guaranteed engine output) it's likely the scatter is caused by measurment errors.

And given the fact that speeds match better with other tests at high altitude, it is probable that something is not right in the V15A measurements (error can be anything; failing device, typing error, calibration problem etc.).

Which can be entirely ruled out given the fact that the low altitude measurements with the V15a were done on a four way record track, the aircraft having flown in four directions, and the (known) distance covered was timed. This method is by far the most accurate and eliminate all possible instrument errors.

[NZtyphoon]

On the other hand this thread is about how the Spitfire I and II series performs in CLOD 1.08, which has now been supplemented/superseded by 1.09, not about Kurfurst's interpretation of 109 data which we all know will be skewed in one direction - how about another thread for that?

Fact is neither patch has provided authentic Spitfire performance, with or without +12 lbs, and there are still chronic overheating issues that ATAG_Dutch has helped alleviate.

[Kurfürst]

Originally Posted by NZtyphoon

On the other hand this thread is about how the Spitfire I and II series performs in CLOD 1.08, which has now been supplemented/superseded by 1.09, not about Kurfurst's interpretation of 109 data which we all know will be skewed in one direction - how about another thread for that?

Thread title says: " Spit/109 sea level speed comparisons in 1.08 beta patch"

Updated paper with French trial results included.