109 e4 performance

[Robo.]

Originally Posted by Crumpp

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

There is a good reason to challenge any data if we really care to have the planes modelled correctly, e.g. close to the so called 'real life'.

First of all, the actual limit range is massive. (btw. I very much agree with Stormcrows insight regarding the tolerance and actual treshold being slightly lower that 500km/h, which plus some subtle variation within that treshold as he suggested would be a superb feature! (for all planes obviously))

Also, there is no details such as what engine and what settings exactly would result in that top speed. If thats DB 601Aa at full power (1.45ata / 2500 RPM), that is absolutely OK.

[Robo.]

Originally Posted by cheesehawk

I think its a combination of both sides, you're defending a shot down plane fixed with non-experts using French parts and who knows what else,

If that message was ment for me, then no, I am challenging both Mtt and French test and take them with pinch of salt for good reason imho. I am certainly not defending the French test, please read my previous posts.

[TomcatViP]

Originally Posted by Robo.

...which plus some subtle variation within that treshold as he suggested would be a superb feature! (for all planes obviously))
....

It's alrdy in the game I think at least for the Hurri.

I have the impression that this is a never ending discussion.

The fact is any tests can and should be taken with a grain of salt. But what other evidence do we have in order to come to a conclusion what should be the max speed for the 109E?

Currently we are turning in circles.

There is the fraction that wants the centre spec line as the reference, others like me say we should take the scattering of the 13 planes from the 109G series with respect to the 109G specs, transpose it to the the 109E and its spec (by miracle we will find ourselves in accordance with all test data of the 109E known to us) and take the mean value. That's what I as an engineer would do (and many other colleagues too I am certain). This mean value would be about 485-490 kph. Perhaps in the future we can have a Gaussian curve with an appropriate sigma (my suggestion 1 sigma = 4-5 kph) so that individual planes may differ slightly.

Perhaps in the far future we can have (offline at least) planes subjected to wear so they will loose a little of their performance with time (for instance if they have had to undergo repair or so).

[robtek]

What i still don't get is: where comes the "agreement" from that the speed was reached with a DB601Aa from?

Wasn't the Aa the export version with more hp but lower full throttle height?

A feature absolutely not needed where most fights started well above 5000m.

[Crumpp]

support my opinion that for the 109G the type was on average below the centre spec line

That is not proof. It is just the reality of aircraft. Even something as simple as an annual has resulted in the need for a complete readjustment of my propeller rpm to reach rated performance.

That my airplane flew below standard on its test flight after annual does not mean it is a sub performing example.

Crumpp says
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.

I am going to bow out and let you guys continue without my input.

[JtD]

It's interesting to see that while the specified speed was 656 km/h, the average of the measured performance was just 643 km/h. And it's still not up to specification when excluding the unacceptable values.

From my experience, this is what you can typically expect. It's human nature to do things as good as necessary, and if both +5% and -5% are as good as necessary, you'll find the more items near the -5% limit.

But I think Kurfürst has nailed it in the meantime: If the in game speed of the 109 E at sea level is below 475 km/h or above 525 km/h, it is wrong. Everything else is a matter of taste.

[Robo.]

JtD - exactly! The problem is that the 475-525 km/h range is simply not good enough if you try to model an airplane for the sim

robtek - The DB 601 Aa was widely used in Battle of Britain E-3 and E-4s

[TomcatViP]

What a crazy little talk we've got there. I'm waiting for such arguments when it will come to talk abt any Spits Mk max speed and xxlbish boost.

With many respects, if the 109E max speed was stated as 500 that is that the vast majority of planes delivered did reach that value with only a few being in the minus 5% range.
In other word, once contracted Bf (Me) had much more interest in targeting the 500 +5% to get the necessary nbr of planes out of production line accepted than saying its engineer : Ok guys the min value is that so let's cross our arm, raise our boots on the desk and let the min value be a standard.

Does it happends that a plane does not meet the contracted spec ? .... Yeah and in deep trouble is the manufacturer. Even in an all out war (I am thinking at the Me410 that was rubish in term of manufacturing standards).

SO let's be raisonable and assume without too much headaches: 95% were in 500ish and 5 % were 475+ish. Some rare birds will do more evidently.

Storm had that in mind (I am not a stat specialist) but I think that he seems to be on the right track. Gaussian is how it shld be

And by the way if the spit was in 500- range any one here with e sense of history shld understand that the 109 has to be in 500+. Just look at the racing examples made out of both those plane : Spit : 630/650 / 109 700- (not the 209 - don't mistake me)

By the way there is not a single serious history book that will give you a value significantly under 500 for the deck max speed of the 109. Why shld we hve this here ?!!!

This is boring

[JG53Frankyboy]

Originally Posted by robtek

What i still don't get is: where comes the "agreement" from that the speed was reached with a DB601Aa from?

Wasn't the Aa the export version with more hp but lower full throttle height?

A feature absolutely not needed where most fights started well above 5000m.

that this 'a' stands for "Ausland" is a myth.
comparable to the E-3 with three canons in active service.