109 e4 performance

[TomcatViP]

I don't know who put the variable s/c case frwd but the chart above posted by Bugmenot show precisely that there was none

One 1946's like hypothesis that can be thrown away

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I dunno how you conclude from bugemots chart that there had been no variation in speed from one plane to another. Actually Kurfürst's chart clearly provides proof that there had been significant scattering in speed. Indeed this chart is highly interesting as one might be able to transpose the scattering in speed to that one for the Emils.

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more. However it also shows that the real obtained mean value would probably be below the 500 kph because only three of the 13 managed to surpase the theoretical mean value of the spec.

[CaptainDoggles]

Originally Posted by 41Sqn_Stormcrow

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I dunno how you conclude from bugemots chart that there had been no variation in speed from one plane to another. Actually Kurfürst's chart clearly provides proof that there had been significant scattering in speed. Indeed this chart is highly interesting as one might be able to transpose the scattering in speed to that one for the Emils.

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more. However it also shows that the real obtained mean value would probably be below the 500 kph because only three of the 13 managed to surpase the theoretical mean value of the spec.

If you're familiar with statistics, you'll know that 13 aircraft of the 33000+ that were produced is not a representative sample.

The mean certainly could have been lower than 500, but it just as easily could have been higher. This is why I think it's silly to use anything other than this figure.

At least Microsoft was satisfied with testing only 13 aircraft. So why should we be less.

Oh, and I am very familiar with statistics. But I tend to adopt a pragmatic approach to problems. We do not have more than these 13 figures and we have to work with what we got. Anything else is just pure guessing around.

[CaptainDoggles]

Originally Posted by 41Sqn_Stormcrow

At least Microsoft was satisfied with testing only 13 aircraft. So why should we be less.

It's a matter of opinion I suppose.

Oh, and I am very familiar with statistics. But I tend to adopt a pragmatic approach to problems. We do not have more than these 13 figures and we have to work with what we got. Anything else is just pure guessing around.

I wasn't implying that you weren't familiar with statistics, please accept my apologies if you took it that way.

[Robo.]

Originally Posted by 41Sqn_Stormcrow

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more. However it also shows that the real obtained mean value would probably be below the 500 kph because only three of the 13 managed to surpase the theoretical mean value of the spec.

That's highly possible, the question is (still) what engine, what ata, what RPM, what rad settings etc etc. If we talk about DB 601Aa at 1.45ata, 2500RPM and rad nearly closed, that's about right. If we get certain variability (say +- 3 percent), that would be fantastic as some machines would be able to get above the treshold as in real life perhaps.

I would really appreciate to get some opinions on numbers.

The chart with the 13 planes tested is with respect to the 109G so we cannot transpose the absolut numbers to the 109E. But it is a sound assumption to transpose the grade of scattering to the 109E imho. That is what should be kept from the chart.

My guess is also that the 109G figures and the configuration in which they were flown correspond to that set for the spec. Otherwise it would not make sense.

I also assume that the scattering between individual planes is the same as long as they fly at the same configuration whatever this configuration would be. So the scattering will not be influenced by radiator opening or ata as long as all planes use the same ratiator opening or ata.

EDIT: np, Doggles.

[Crumpp]

There's typo in the Baubeschreibung: M o t o r l e i s t u n g

Then the velocity will be ~490kph at that engine setting.

[CaptainDoggles]

Originally Posted by 41Sqn_Stormcrow

But it is a sound assumption to transpose the grade of scattering to the 109E imho. That is what should be kept from the chart

Agree 100%.

In fact from the same factory (retooled for later models) I would expect to see performance variations fall within the same number of standard deviations.

NB to all: Some aircraft perform better than average and some worse. Cherry-picking a handful of tests done on captured fighters does not a representative sample make.

[Crumpp]

The dots are measured values for 13 individual planes - some are a bit worse, some are bit above the specs, and there are couple that will be rejected until the plane is brought up to spec.

Keep in mind it is probable that most aircraft off the assembly line will have squawks that need addressing.

Just because a new aircraft has squawks does not mean it will be rejected. Most are minor adjustments that will be taken care of relatively quickly.

I would expect the majority to perform slightly below average until those squawks are fixed. You can also have optimistic performance that represents a squawk that must be fixed. An adjustment of the propeller governor, fuel metering, timing, etc...can have a large impact on performance.

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more.

Correct. However there is no good reason to believe it is anything other than what Mtt says, the mean performance. They knew much more about their aircraft design than any of us and were being paid to deliver those aircraft. Misrepresenting the mean would have been quickly noticed by the customer.