109 e4 performance

[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.

[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.

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.

Nana, I think there is good reason to believe that the REAL obtained mean value was not on the centre line of the spec bandwidth. This is not how engineering works. The mean value of a produced thing is NEVER on the targeted nominal performance. My years in the engineering business taught me that. I have NEVER seen one produced thing that had its mean value on the nominal spec.

[Robo.]

Originally Posted by Crumpp

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.

There is a very good reason to take their own graphs with pinch of salt just like the tests of captured Emils etc. Just because they're the manufacturers! This is exactly the same all over the world, at anytime, even in 1940's Germany as long there are human beings involved in the process.

It is just matter of opinion if you decide to take Mtt numbers as granted and sacred OR if you take more critical and suspicious approach just like I happen to have taken. I actually believe these Mtt numbers completely if they reflect the Aa at 1.45ata 2500RPM, which is due to be confirmed. It's weird how some of you guys started jumping up and down just because I dared to challenge the Mtt chart (calculated theoretical stuff, pretty much correct, but still not real life data and it has got massive space for variations...)

Interestingly, this discussion keeps revolving around these unlucky Mtt files, but no one contributes anything to the actual topic - E-4 performance in the sim and how to get it 'right'. What is this topic in here for, then?

[Crumpp]

Nana, I think there is good reason to believe that the REAL obtained mean value was not on the centre line of the spec bandwidth. This is not how engineering works. The mean value of a produced thing is NEVER on the targeted nominal performance. My years in the engineering business taught me that. I have NEVER seen one produced thing that had its mean value on the nominal spec.

There is no credible reason to doubt Mtt's figures in the absence of facts.

Crumpp says:
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.

Well I think the Mtt facts (the 13 tested planes that are on average below the centre spec line - 10 out of 13 are below = average < centre spec line) are there that support my opinion that for the 109G the type was on average below the centre spec line and there is good chances that this is the case for any type coming from this company hence also for th 109E.

You insist that these 13 are not representative and keep arguing that it should be the centre spec line that should be taken as the mean value for the 109 while there is absolutely NO fact that consolidates this opinion. Please provide us with some data from test flown 109E that reach 500 kph and more but beware we need data from several individual tests with this result to support your view.

PS: The centre spec line has nothing to say except that this is just the middle value between the acceptance bandwidth. We have no clue that Mtt ever attempted in fact to reach 500 kph (that is this is the aimed nominal value they took into account during the design process) and there is NO facts supporting that the average 109E ever achieved this performance.