I got the ratings, what I wanted was your opinion what the max TAS at 0m shoud be for each engine for each rating (Hoechst - Kurz- und Dauerleistung) - that would be very helpful.

at least he
http://forum.1cpublishing.eu/showthread.php?t=23921
is talking about that both engine variants are programmed, speaking available, in CoD. How 'accurate' and wich 109E has wich variant in game.....smart people have to look in the code i guess ;)

I think if we agree that standart 109 E-3 with Db601A at 1.3 Ata 2400 RPM 1/4 radiator open reach 467 km/h at deck ( from German test) it is sure that speed could be calculated for other power setting and also for Db601 Aa with high probability.

Absolutely.

It is a legal binding document that the customer does not have to pay for the aircraft if it does not reach the stated performance. There is no guessing required. Once more as already stated, both Mtt and the Luftwaffe confirmed that performance before that aircraft left the factory.

Using a prototype, Bf-109EV15a from 1938 with a new type engine at the time, DB-601A. A new type engine that Daimler Benz is saying does not reach its rated power yet but will in the near future.

Bf-109EV15a is for a fact not representative of a front line fighter two years later.

It certainly is not proof of any form of "optimistic" manufacturer's performance.

There is a lot of debate in some very knowledgeable circles about the engine used. It was either a DB-601A1 or a DB-601Aa as the DB-601A was never an 1100hp engine.

The 5 minute rating is either 1.3ata (DB-601A1) or 1.35ata (DB-601Aa).

We will give him a chance. I make mistakes, especially when I rush or am not all that interested. I also think robo is trying to learn.

This particular debate over Bf-109E WNr 1304 has been ongoing for years among a much more knowledgeable crowd, no offense meant to the IL2 Sturmovik players.

Even lining up the original Baumeister Datum for WNr 1304 has not solved the issue. It was built at a time when both engines were being delivered to Mtt. Without the engine Werknummer, we may never know.

It is not accurate without the pressure data.

I don't see anything wrong with the radiator drag. It seems typical for a liquid cooled engine installation.

The climb performance is also typical for a colder than standard day. They did get better climb results than Mtt but their climb power settings appear off. Their rpm is high, which makes a difference and so is their manifold pressure.

All of that is secondary to the fact they performed the climbs on a colder than standard day.

Of course. No one ever stated in this thread that any Emil accepted by the LW has failed to meet the specifations agreed in the contract. What I dared to say was that the tolerance was rather generous at 50km/h, and we can not assume automatically that the actual performance of Aa Emils was always 500km/h. I suggested certain variability to be modelled (for all aircraft obviously). Please read properly. ;)

Just what I said, engine not quite ready + small important flaws in finish and lack of manifold exhaust covers. The test is interesting in certain aspect but no one ever suggested modelling the ingame A-1 Emils according to the charts.

I know this and it has nothing to do with what I wrote. I was simply asking how do you think the Emils with both A-1 and Aa should be modelled in game including the limits of the ratings. (Especially regarding the top speed at the sea level to start with). My reply was to Kwiatek simply to point out at different character of A-1 and Aa engine, because he did not make any difference between these 2 in his original post.

Yes you did quite a lot of mistakes, mainly due to the fact you don't read properly what the others have to say and you somehow assumed that everyone except you doesn't know anything. ;) You're learning, too dude, that's OK.

It is good enough given the information available. My point was that the value seems to be reasonable for the sim imho.

That's right, but it is clear the French had some cooling issues and at one attempt, there was (unspecified) engine malfunction. All I said is that this test is a bit dodgy, too, just like V15a. The 50km/h difference is some 5-10km/h too big when compared to other test. I believe this is due to different ata setting during the two flights being compared at 5000m.

They got worse climb results. ;)

And yet, they were overheating, perhaps those higher RPM and different components and coolant as mentioned in the notes. Who knows... But one is for certain - 1304 just as V15a test is interesting and informative, but not really usable.

So can you please say what do you think the top speed for both engines with all 3 rated MFP/RPM from the above chart would be? In your opinion?

Of course not, 500km/h is just the mean.

Right, we agree on it.

Ok, I might do that for you if I have the time.

5-10Km/h is nothing. It could be bugs on the leading edge and windshield....

This is why I don't get too involved with these kind of discussion's. You claim I think I know everything. Well, I don't. I do know airplane performance and the science of flight.

It winds up being an argument over every little point.

Ahh so they did. Interesting but I think if you check out their radiator settings and compare it to what the Germans used you might find your answer.

They flew a large part of that climb regiment with radiators fully open and an engine on the verge of overheating. I imagine the fuel metering system set up for synthetic fuels did not like the French fuel.

Different components is the oil and coolant. Additionally the French though the speed range is the same as the climb range. It is not. The percentage error over mean for climb performance Mtt says is 8%.

Given that, even with radiators open, the climb performance is within 7 seconds of the German results at 1000M.

One thing about recording climb performance. It is one of the hardest areas of performance to nail down accurately because it depends on so much that changes.

The French instrument error is 3% too.

Thanks for the reply Crumpp - as you see I am not in any kind of disagreement. The calculations are not really for me, rather for the sim. I find it interesting and if the 1c guys happen to read this or if it gets reported, we might as well end up having Emils closer to the real thing FM-wise. I know I am naive :D

5-10 km/h - i got your point point, but it is really about these small details and I pointed out that the 2 flights compared (rads open / closed) at 5000m were at different MFP and the difference was perhaps smaller than 50km/h.

Also agreed on the climb performance -most difficult to measure as enviroment is a massive factor. Funny thing is they got the top speed right and climb so much off when the a/c was the same. I also believe it might be fuel / coolant / oil / instruments. I also believed that particular 109 has been slightly damaged before - hence the 'components' thought, not just fluids. No further info on that provided...

As for the actual figures and calculations for top speed at sea level:

DB 601 A-1 / 9-9518A

1.40 ata 2400RPM 1100HP (1 minute)
1.30 ata 2400RPM 990HP (5 minutes) radiator 1/4 open 467km/h
1.?? ata 2200RPM 810HP (30 minutes)

DB 601 Aa / 9-9518E

1.45 ata 2500RPM 1175HP (1 minute)
1.35 ata 2400RPM 1045HP (5 minutes)
1.15 ata 2300RPM 950HP (30 minutes)

Anyone cares to fill in the blanks, ideally rad fully open / rad fully closed + E-3 E-4 aerodynamics + /B aerodynamics?

I understand what you want to say and I can partially agree. But only partially. The manufacturer's specification of 500 kmh +/-25kmh does definitely not mean that the 109 reached 500 kmh but probably something less. I however doubt that all 109s will have been on the lower band. This would be basically impossible in terms of production. I also doubt that the manufacturer aimed at achieving 475 kmh, as was suggested earlier by somebody. This would be a dangerous policy for a private company because aiming at 475 kmh (meaning average performance of 475 kmh) would have meant that many many fully assembled planes including engine would have been rejected. Assuming a natural Gaussian distribution of performance this would have equated to a almost 50% rejection. Not one company can afford this. So my guess is that the average in tems of performance will have been well above the 475 kmh. However difficult to tell where it was. Probably somewhere between 475 and 500 kmh and the French test seems to concord with this. Perhaps they did have an optimistic plane. So one might guess that the average would have been at 485 kmh with a dispersion of perhaps 1 sigma = 3 kmh that is with a variation of +/-10 kmh at three sigma. This would make sense from a production point of view to have the lowest performing aircraft of a batch to be at 'average minus 3 sigma'.

hm, if the manufacturer was able to determin speed output to such a degree that the flight range was between 475 and 500, why then the much larger safety margin up to 525? leftover from times output varied much more?

41Sqn_Stormcrow - dude you said exactly what I said ;)

Perhaps selling issues. Sounds nicer to have a spec at 500 +/-25 kmh than 485 +/-10kmh.

The thing is there seems to be no test on the E series that indicates that there had effectively 109s that reached speeds above 500 kmh.

It is an average. There is no "probably something less" or "selling issues". No pointy tin-foil required. This is standard stuff in aviation.

Of course there are flight test's that show that average performance....

Here:

http://kurfurst.org/Performance_test...chreibung.html

That is the Yugoslavian test we've had here few pages back. There is no mention of the aircraft actualy achieving 500km/h, at least I can not see it anywhere.

It is German test but is reprinted in a Yugoslavian report. Of course it is, the Yugoslavian's purchased Bf-109E's...

The Yugoslavian report is used to date the German one.

Sure there is:

They flew at full power for 1.1hours, to altitudes of 6000m, and the total flight lasted 2 hours.

http://kurfurst.org/Performance_test...chreibung.html

Ok, we can ballpark the vicinity of the speeds we should be seeing at each of the settings by using the basic math relationships of power required to power available. Most of you won't know what I am talking about but it works.

For these ratings:

2) Startleistung 1175 PS in 0 m Höhe = 500kph
(zulässige Dauer 1 Min.)
bei 2500 U/Min.

3) Bodenleistung 1015 PS in 0 m Höhe = ~474kph
Kurzleistung (5 Min. Dauer)
bei 2400 U/Min.

Erhöhte Dauerleistung 950 PS in 0 m Höhe = ~465 kph
(zulässige Dauer 30 Min.)
bei 2300 U/Min.

Dauerleistung 860 PS in 0 m Höhe = ~449 kph
bei 2200 U/Min.

That is based on Mtt's contractual performance with the RLM and of course has a +/- 5% and assumes the radiator is in the same position as the 1 minute rating. This is a quick ballpark and it can be refined.

For those not familiar with the math:

http://mit.edu/16.unified/www/FALL/t...es/node97.html

I really have no clue where you find the test-flown 500 kph ... please indicate the corresponding paragraphe or sentence.

Proper translation:
"Endurance at full throttle is 1.1h at 6000m altitude.
With according throttling, endurance is increased to two hours."

It's the part of the technical description labelled "Endurance".

I know that, but the actual data is (again) the same Mtt data, the only source provided by the manufacturer. It even says so in the description.

I speak German but I honestly can't see this test confirming the Vmax values stated in the manufacturer's brochure.

Thanks very much. I put it into the table posted earier. Only difference (probably typo) was the PS for Bodenleistung. What is the position of the radiator? What would the values for A-1 be? What would the drag penalty for E-4 Haube be and what would the drag penalty for bombrack be, if you happen to know?

DB 601 Aa / 9-9518E

1.45 ata 2500RPM 1175HP (1 minute) - 500km/h
1.35 ata 2400RPM 1045HP (5 minutes) - 474km/h
1.15 ata 2300RPM 950HP (30 minutes) - 465km/h

What else are you looking for?? I mean seriously, your whole premise is that Mtt is lying and will get paid for thousands of aircraft despite that presumption.

Does that really make any sense?

Crumpp, I never stated Mtt was lying :o I am simply trying to find exact values that could be considered reasonable (not too optimistic, not too pesimistic) and as such would be usable to model the Emils in the sim. I am not arguing with you, I am just asking more questions. I understand if you're not interested or too busy and won't reply.

What you wrote and calculated is in acceptable agreement with the real life tests (467km/h for A-1, 2400RPM, 1.31ata 990PS)

Oh and yes, it does make sense, thank you dude.

There's no such thing as an exact value in engineering. EVERYTHING has a tolerance.

• That hole you drilled? Only accurate to within ±1mm.
• The elastic modulus of steel? It's a statistical range that depends on the microcrystalline arrangement of the atoms.
• The shear stress of your wing spars? Depends on the cross-section which is not accurate because of tolerances in the manufacturing process.
• Horsepower you get from fuel? Depends on chemical composition, which is again subject to tolerances and impurities introduced when it is refined and processed.

Robo the Dennis
 

[QUOTE=Robo.;355377]Quite OT dude :o I happen to agree with Crumpp in almost all of the things he wrote, I dared to comment his attitude and pointed out that everybody is making mistakes. Nothing to do with you, Sir. ;)

HE-He, such a polite poke in my eye:rolleyes: Yes we ALL make mistakes, eh?

Please, as they say in the Army, "Don't call me 'Sir,' I work for a living.;)
But why all this concern about top speed? Surely you don't just turn your favourite LUFTWAFFE plane and run from a fight!!! I suggest some maneouvring might help:grin::grin: (I always have trouble spelling 'maneouvre' - if it is wrong I,m sure you will be kind enough to correct me.

Turn fighting is for suckers.
Either initiate the attack with a firm advantage or disengage. Never fight fair.
Hence the need for speed!

Twisting and turning with the RAF fighters is a good way to get shot down. Speed is life.

Maneuver (US) and Manoeuvre (Commonwealth) are the two spellings, I think.

Jumpy Jumps
 

Thanks to all for your good advice, especially the spelling!
Fighting was never my strong suit. Head down, get in close and use the elbows, knees and fingers has always been my style. Of course, thinking back, I lost heaps more than I ever won. Thank God the Testosterone ebbs..

Bailing out (old skydiver) been out maneuvered..manooovered:grin::-x:grin::-x

Explain how the presumption Mtt is lying on their building specification and contractual speeds makes sense?

If you want to become a better combat pilot, I'd recommend taking a look at the following:

In Pursuit

Fighter Combat: Tactics and Maneuvering

And I'd also recommend posting threads in the gameplay forum if you want help or have specific questions.

I really can't understand why there is still disagreement about the max. speed of the Bf109E.

When the manufacturer calculates a speed for a model and verifies this with flight-tests, and sells the plane according to this values

to a known nitpicking customer, the values must be correct or the manufacturer is out of business..

The interest of the manufacturer is to get no rejects, so the production is streamlined to minimize the tolerances.

There is still no real pressure on the manufacturer at this time (1940) to meet the demands, so peacetime quality can be assumed to be met.

When we have now a projected max. speed of 500 km/h i would think that the majority of delivered Airframes met or surpassed this speed.

As even slight faults of the airframe or the pilot would mark the plane as unacceptable, the manufacturer will try to err to the safe side.

Actually, the only thing that one can deduce from the manufacturer's spec is that the maximum speed for a 109E that were delivered would be at least 475 kph. I would never venture so far as to say that the average of all delivered 109Es would be at 500 kph. We simply don't know. The 500 kph +/-25 kph is just a bandwidth resulting from negotiations between the client and the company.

So the average may be anywere between 475 kph and 525 kph when only consulting the specs.

What really matters is the real obtained speed value for each plane. To know where the average was one would have to measure the max speeds for every plane under the same conditions. As all planes were test flown there might have been abundant data albeit probably not under same conditions (weather, pilot, ...). They might also just satisfied themselves with proving that they can reach the 475 kph.

Now we only have a handfull of test data available, all with max speeds below 500 kph. So unless we find test data that shows that the 109 could reach 500+ kph I would assume that the average was somewhere between 475 and 494 kph.

CaptainDoggles - this is pretty much what I was talking about, I would really appreciate having certain variations in parameters and performance (I actually believe such a thing is present in the sim now, at least overheating behaviour...). What I am trying to do is, to come with something constructive, e.g. some numbers usable for the devs, from which these say Vmax ranges for the aircraft in the sim might be calculated.

There is no disagreement at all. :o As you say, manufacturer calculated speeds in certain conditions, but he never verified them with flight tests. The main reason being it was not really possible, the data are simply theoretical speeds. All that is good enough, but these speeds never achieved in any actual empirical tests (again, various reasons). The problem is that this is a matter of opinion. Mine is that average E-4 with DB 601Aa engine was well capable to reach 500km/h at 1.45ata ('1) (take-off power at sea level, rads fully closed or 1/4 open), but it would be unwise to model all Emils in the sime like that or even worse, using more optimistic data (say 525km/h) for average plane in the sim. Therefore, I was trying to come with some rough guideline and some numbers for rated power for bothe engines in questions. I believe this can help getting the FM right (regarding how the real thing flew including certain variability) more than comparing each other opinions.

I pretty much agree with 41Sqn_Stormcrow's insight above, Crumpp's calculated data are still very close and good enough for the sim (Aa engine).

I agree, this book is a gem.

Very OT, but can't disagree more. Surely, speed is life (even in turnfight), but a good pilot must know how to swing the plane around if it comes to that. And it does sometimes ;) Different topic I know, but fighting in maneuver (not necessarily turn) is not for suckers but for pilots who know what they're doing. :grin:

Well basically we can say: the 109 as modelled in the sim is too slow (there is no speed variation in any plane so the in game 109 can be supposed to represent the average 109). It is even slower than the slowest ever performed flight test (on a special unit). It is well below the minimum spec. Conclusion: the 109 should be faster by a good deal. As there is currently no test data concluding that the 109E could reach 500 kph and the best ever obtained data in the tests that we dispose of is 494 kph the average should be in the middle of the 475-494 kph range for the average 109. This is about 485 kph. In case the devs will implelemt a variation they should apply a gaussian with average value 485 kph and 1 sigma = (485-475) / 3 = 3.3 kph.

Now I hope we can have a similar evaluation for all the other planes including the Spit 2a that seems to concord with some data given but we also should evaluate if it is based on average values or if it is based on test data that was more on the upper bandwidth than on the lower (or vice-versa). There is currently no clue whether the Spit 2a is representative of an average Spit2a or a lesser or better performing individual plane.

I still would say that the average, fresh from the factory, Bf109E should be able to reach 500km/h!

Of course the speed later on varies, depending on how the machine is handled.

If the machine is handled carefully, always warmed up enough and never exceeded the power ratings and also didn't have

accidents during the ground handling or damage through enemy action, then it might be even better then during the acceptance trials.

Otherwise, if one or more of the above conditions isn't met, the speed will be lower.

But then, if the speed and/or handling has detoriated to a given point, the aircraft will get a major overhaul or be sent to training units or wrecked.

If there is a variation from the factory-set standard speed it must work both ways, or it is biased, imo.

I'm pretty sure we've just spent 4 pages establishing that not only did Messerschmitt conduct test flights to verify their numbers, but so did the RLM. Use logic for a second: If, as you say, nobody did tests between the aircraft coming out the door of the factory and going to operational service, then how did the RLM know they were getting what they paid for? How did Mtt know that the RLM wasn't trying to cheat them?

Answer: They did flight tests. We just don't have the documentation.

Are you seriously saying it was "not really possible" for Messerschmitt to conduct flight tests? These are not theoretical speeds, it's a requirement that Messerschmitt was obligated to meet.

I see your agenda beginning to show. What you mean to say is: We don't currently have access to any empirical tests where this performance was achieved. Or perhaps: The (very very small) sample of aircraft that made their way into the hands of the Allies did not achieve rated performance.

Indeed Messerschmitt did proof checking of their airplanes. I've only seen one such paper, this is for Erla licence-produced Bf 109Gs. You can see the nominal (guaranteed) performance with a thick line, and also the upper and lower tolerance on performance (+/- 3%) for acceptance.

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.

http://www.kurfurst.org/Performance_...catter_web.jpg

The story in short is, however, the nominal specs are guaranteed to be reached within limits. An aircraft is just like any product, the producer has liability to meet the agreed contract, no matter when, and where. In Germany, the LW had its own separate quality control organisation, the BAL. They were pretty strict right until the war's end. Reading Hans Fey comments on Me 262 testing, the lower limit for the Me 262 was 830 (nominal/guaranteed spec was 870 kph), they did accept planes down to 825 but that was it; anything lower would be rejected. And that was in 1945, when the Germans would need as many jets as possible.

http://www.lwag.org/forums/showthread.php?t=484

Now the bottomline: As shown in the Baubescreibung Me 109E document, the specs for the 109E were 500 km/h at SL and 570 km/h at altitude with 1.35 ata or full power and the DB 601Aa engine, within +/- 5 % of that for each individual plane. We have exactly that aircraft modelled in the sim, so E-1, E-3 and E-4 should satisfy these specs. If they are modelled different, its wrong, end of story.

There's typo in the Baubeschreibung: M o t o r l e i s t u n g
http://kurfurst.org/Performance_test...chreibung.html

should be 1045 PS in 0 m Kurzleistung (5 Min. Dauer)
bei 2400 U/Min.

http://img133.imagevenue.com/initial...orleistung.jpg

Of course they did, but did they really strain a brand new engine to verify the max speed on the deck? If you have any further information about the tests conducted by RLM / BAL in order to accept an airframe they have paid for? That would be great to know, but using logic again, would their test pilots push the new a/c to its limits? I believe they would not and if the plane performed within limits, they were happy.

No, I never said such thing. :o I never stated that Mtt failed to deliver what they were legaly bound to. I said they most probably did not perform extensive tests to prove our point. The fact is, no matter what test you look at, no aiframe ever managed to reach the speed in the Mtt chart. That brings you straight back to the beginning of this discussion.

I've got no agenda at all, I only have interest in aircraft portrayed in the sim and I enjoy discussing them. I said - any many would agree - that the tests available are far from being representative (for various reasons). I also said that the Mtt data is theoretical and can be considered optimistic in relation to the real life performance. Many would disagree and I respect that, especially if that's supposed to be a performance of Aa engine on take off MFP ('1 rating) - fair enough.

I tried to get some figures to the respective rated power of both engines in question in order to establish some base. I find it interesting and I enjoy thinking about such details. There is nothing more to that, perhaps except my wish to have the a/c in the sim as close to the real thing.

What is your opinion on the actual figures, CaptainDoggles?

I agree, the problems is how to model this in the sim. Crumpp replied earlier, and I have no objections at all, because that sounds very reasonable, the max speed stated was reached on an Aa engine, 2500RPM 1.45ata, rads 1/4 open (or closed). That plus some variation modelled, e.g. some Emils would do slightly more and some slightly less - that would be great.

They actually satisfy these specs on the very bottom end. They should certainly be slightly faster on the deck. My point is let's get some figures that might be acceptable for the sim for both Emil engines on all ratings, ideally for all rated powers mentioned in the chart.

Interesting info about the Erla Gs, seen that one before on your website. Does not say anything about top speed being tested on the deck and I can't read the doc good enough to see the actual ata settings etc.

I pointed out that typo already and it has been already corrected in the chart I am putting together, bugmenot. ;)

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 :rolleyes:

That's for DB 601Aa indeed. The problem is obviously the huge tolerance of 50km/h - and also, I can't seem to find anything confirming the ata used to achieve that speed. Was it Bodenleistung or did they push it on 1.45ata? Do we know? Makes quite a difference.

It's not that easy I am afraid - the Aa and A-1 were slightly different. We don't know which engine is modelled in the sim for each subvariant. That's why I am trying to get some numbers together for both. ;)

It's not "straining" the engine if that's what the engine has been designed to do. The engineers say "you can run at XYZ power settings for 5 minutes." Why would the RLM pay for aircraft they aren't sure can meet the contracted obligations? They must have verified that the aircraft can deliver. It's a simple fact, and continuing to cover your ears and sing LA LA LA LA in face of this fact makes me think you are just another forum troll.


Either they tested enough to ensure the required performance was being achieved or they did not; there is no middle ground. Either the aircraft met the requirements or it didn't. There is no middle ground. You can't say "I'm not saying they didn't deliver what they were required to deliver" in one breath and then say "they didn't do extensive testing" the very next. HOW DID THEY KNOW WHAT THEY WERE DELIVERING IF THEY DIDN'T VERIFY IT WITH TESTING?

And again you're trying to make it sound as if every single test ever conducted on the 109E shows it not meeting proper speeds. Guess what? We don't have the data from every test ever. Stop trying to re-frame the issue based on your agenda.

----

I'm done engaging with you on this subject. You next post is going to be another one saying that the contractual obligations were actually just imaginary, theoretical numbers and blah blah. I don't have the patience to repeat the same facts over and over and have somebody just ignore it and say "but I think it's this way" so I will leave you to it.

?
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.

No, I am not another forum troll, just because I don't happen to have the same opinion like you. Please keep this unpersonal. ;)

I am asking a simple question(s): Did they try to fly the airplane at full power at the deck as a part of the test? Did they verify the performance by attempting to achieve the top speed at any other altitude? They obviously did - and seeing the aircraft producing MFP / RPM expected, they simply assumed the curve as such was met within limits. We don't know, unfortunately, what ata they have been using. Other inspections (instruments, equipment etc.) were more important and if they were happy, they did not send the a/c back to get any issue fixed.

How do you think the Emils in CoD should be modelled?

No, I am not. :grin: Please read my posts again if you care. I am just asking what the 'proper' speed should be.

That's OK with me dude. I am not saying any of the above, I simply don't see it as black and white as you. No need to get emotionally involved :grin:, if you can't answer my questions by providing some facts, that's fine. I respect your opinion and I don't ignore it at all, but I keep mine until I get enough facts to adjust it. We are not about change anything anyway so please take it easy.

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.

It's a matter of opinion I suppose.

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.

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

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.

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.

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.

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! :grin::grin: 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?

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

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.

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.

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. :o

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).

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 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.


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

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.

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

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:evil:

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

I hope so ;)

Statement is not good enough, especially when it comes from the manufacturer. Ok I see your opinion, now we need to get some evidence and exatc numbers. So, again - what engine, what settings etc?

Of course, but what settings, what engine, what about the other rated power? This is not a history book with a figure, this is a flight sim.

Don't read it then dude ;)

Well I am only reading the illustrations when I am reading history .... but I hve to say that the technicals details in red little riding hood were a bit tricky for me ... ;)

According to the discussion here http://forum.12oclockhigh.net/showthread.php?t=5585

the DB601Aa was used for the fighter-bomber 109's, Do215 and so.

That's not really what is being said in that forum at all :o Did you have a look at the info I've sent you via PM?

One thing i have tested, FTH for the Bf109 in the sim is 4.500m, so it must be the DB601A1 modeled.

It's the A1. There's an Aa in the game as well but no aircraft use it currently. Both the Aa and A1 have 1020 PS listed as their "maximal power" ratings, whatever that means.

RL data I've seen says that at 2400 RPM at FTH the BD601A will make 1020 PS but the Aa should be higher, and both should be much higher at sea level. Possibly this is the reason.