109 e4 performance

[Bpdslayer]

I know I'm gonna get flamed for this... But is anyone else having problems staying sliced vs spitfire mk2's online? Seems to be the case that one on one the 109s can't hold their own against the mk2's and the only option is to run for ur life.... Other than that the 109 is a joy to fly! Oh maybe one thing can be done agains the mk2. That is to split-s, i can shake the spit off my six but can't turn it into an advantage. To the 109 pilots out there, is your experience online similar?

[JG53Frankyboy]

read here
http://forum.1cpublishing.eu/showthread.php?t=25956

[41Sqn_Stormcrow]

Mh again something on the proppitch.

I noticed that during automatic pp control on the clock moves very slowly. Ok this may be due to the mechanism behind (somebody has some knowledge on the proppitch speed during automatic mode?).

But what I think is wrong is that during manual mode the prop pitch is as slow as was the 109E3 before this patch. I think this is wrong and in manual the speed should be like that of the 109E3 that is 4sec for one hour on the pp clock.

[IvanK]

I am getting 6 secs per Hour of clock movement on all types in AUTO or Manual. That represents 1.0 deg per sec of actual blade angle change. Ideally we should be seeing 1 Hour of clock movement in 4 seconds ... representing 1.5deg sec actual blade angle change.

[Welshman]

the e4 was never as fast as the spit anyway so there lol :-P

[41Sqn_Stormcrow]

I am getting 6 secs per Hour of clock movement on all types in AUTO or Manual. That represents 1.0 deg per sec of actual blade angle change. Ideally we should be seeing 1 Hour of clock movement in 4 seconds ... representing 1.5deg sec actual blade angle change.

Mh. I am quite often flying the E3 and with the latest patch the pp is really fast. I did not measure it but it seems to be about 4sec per 1 hr.

[VO101_Tom]

Mh. I am quite often flying the E3 and with the latest patch the pp is really fast. I did not measure it but it seems to be about 4sec per 1 hr.

6 sec

[CaptainDoggles]

I think it's pretty well-known that the Spit Mk 2 is getting historical performance while the 109s, hurricanes, and Spits Mk 1 are not performing as well as they should.

I personally just avoid servers with the Mk 2.

[TomcatViP]

You mean infinite turn perf and zoom better than the 109 as being historical ? No thx !

Cutting somebody arm does not stop him from sneezing herr Doctor ;)

109 and hurri are just fine IMHO.

[Welshman]

I think it's pretty well-known that the Spit Mk 2 is getting historical performance while the 109s, hurricanes, and Spits Mk 1 are not performing as well as they should.

I personally just avoid servers with the Mk 2.

so how fast should a E4 go level flight ?

no idea if this site is accurate or not ? http://www.spitfireperformance.com/spit1vrs109e.html

[Crumpp]

no idea if this site is accurate or not

The story is much deeper than what is presented.

The newest data on the Bf-109E on that site is December 1939.

The Bf-109E is not using C3 fuel or a CSP.

Both were in use during the Battle of Britain.

You can sum the truth up as "Some Spitfires were faster than Some Bf-109's and none of them under all conditions....."

[Kwiatek]

Is is quite hard question actually how fast 109 E-3/E-4 was at the deck.

Most data claimed for 1.3 Ata power ( 5 minut emergency) - 460-467 km/h

Probably it would be at 1.42/1.45 Ata (1 minut emergency) about 480-500 km/h.

German manual for E-3 claimed 500 km/h at deck.

Spitfire MK1 at 6 lbs reached ab. 460 km/h and at 12 lbs ( 5 minut emergency) reached 505 km/h.

Hurricane MK1 at 6 lbs reached 426 km/h and at 12 lbs reached 460 km/h.

[CaptainDoggles]

so how fast should a E4 go level flight ?

Well, speed depends on altitude, but here's a test conducted by the French in 1939 on a captured Bf 109E-3 that appears to reach approximately 490 km/h at sea level.

[Martin77]

Hi all :grin:

I think the */B Versions of the BF109s are a little bit slower due to the bomb rack. When i test a flight at 1000m and 1.3 ATA and 2400 rpm i reach 420 km/h. Thats 25 km/h to slow to original documents from 4.7.1940 see here:

http://www.beim-zeugmeister.de/zeugmeister/index.php?id=52

[Kurfürst]

Official Bf 109E specifications, guaranteed by manufacturer within +/- 5%. All Bf 109E accepted by the Luftwaffe had to fulfill these specifications for acceptions within the above limits.

http://www.kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

http://www.kurfurst.org/Performance_tests/109E_Baubeschreibung/109E_Bau_speed.png

In short, our Bf 109Es are 40 km/h short of speed at low altitudes. FM bugs so far prevented to verify if they can reach 570 at altitude (did not test with latest patch. No TAS indicator either)

Spitliarperformance site as usual reports only speed at 30-min ratings, not maximum outputs.

[41Sqn_Stormcrow]

Is this chart with Notleistung?

I am a bit confused. I currently thought that 490 should be normal speed without Notleistung. But now I have some doubts.

[louisv]

Notleistung?

OK... Got it on Wikipedia...Emergency boost.

[Robo.]

Official Bf 109E specifications, guaranteed by manufacturer within +/- 5%. All Bf 109E accepted by the Luftwaffe had to fulfill these specifications for acceptions within the above limits.

I am a great 109 fan and I would like to have all the planes in the sim as close as possible to the real thing. Therefore I don't think it would be wise to get data from the manufacturer specs :grin:

[41Sqn_Stormcrow]

Lol, Robo. Are you a manufacturer? :grin:

[Crumpp]

Therefore I don't think it would be wise to get data from the manufacturer specs

That is the best standard in the aircraft industry.

That is the performance Mtt's guaranteed by contract to the RLM its airplanes would perform. If an airplane did not fall within that +/- 5% then the RLM did not pay for it or accept it as one of the airplanes it purchased from Mtt.

Each airframe was test flown before it was accepted for Luftwaffe service and it had to meet that minimum specification.

[Robo.]

That is the best standard in the aircraft industry.

That is the performance Mtt's guaranteed by contract to the RLM its airplanes would perform. If an airplane did not fall within that +/- 5% then the RLM did not pay for it or accept it as one of the airplanes it purchased from Mtt.

Each airframe was test flown before it was accepted for Luftwaffe service and it had to meet that minimum specification.

Alright, I think we should use the data specified by the manufacturer when they tried to get that contract then. ;)

[SG1_Lud]

Alright, I think we should use the data specified by the manufacturer when they tried to get that contract then. ;)


If it is a question of credibility, between the manufacturer data and that "test" done in France, I trust more in the manufacturer's, for two reasons:

1) if you read in the detail the french test, is clear that it was done far from the conditions you want for a test.

2) I havent heard of a single LW report complaining about the manufacturer's specifications being wrong.

Cheers!

[SNAFU]

Well, manufacturers tend to stick with margins specified and use them, if they have the quality system giving them the ability to mangage the narrow gab. If 500km/h +/-5% on ground level was specified, I would expect the standard plane to leave the shops testified to be able to reach 475km/h, but not one km/h more.

[Crumpp]

able to reach 475km/h, but not one km/h more.

Really???!!!?

:grin:

[Robo.]

If 500km/h +/-5% on ground level was specified, I would expect the standard plane to leave the shops testified to be able to reach 475km/h, but not one km/h more.

That is my opinion, too.

2) I havent heard of a single LW report complaining about the manufacturer's specifications being wrong.

They wouldn't complain to you, dude with a 109 in the avatar ;)

[Crumpp]

I havent heard of a single LW report complaining about the manufacturer's specifications being wrong.

It definitely gets fixed if it does occur. Focke Wulf had an issue with one of its subcontractors, Dornier (NDW) not meeting specifications.

It was discovered when the Luftwaffe was rejecting a large number of aircraft. The complaint was excessive vibration and fuel consumption. It generated several reports on the issue and was fixed promptly. It caused NDW to suffer greatly increased oversight and they almost lost their contract.

[Crumpp]

If 500km/h +/-5% on ground level was specified, I would expect the standard plane to leave the shops testified to be able to reach 475km/h, but not one km/h more.

That is not it works building airplanes. You can get close to the lowest common denominator building a toaster maybe?

[Robo.]

It definitely gets fixed if it does occur. Focke Wulf had an issue with one of its subcontractors, Dornier (NDW) not meeting specifications. (...)

That's fine information regarding the inferior quality of a component supplied by 3rd party, but does not say anything about the overall performance, especially top speed. Of course, quality of the components matters a lot and if they all meet standards, it is very likely that the aircraft as such will meet them. BUT manufacturer's specifications are more likely to be a target, not necessarily reality. I highly doubt that they would stretch brand new engines to see if every plane goes 500 km/h on the deck, returning them to the manufacturer if they wouldn't. :D If the engine ran fine and within specs, they were happy. It was close enough to the specs, some particular aircraft met them OK, but as for the sim, -4 or -5% seems to be reasonable.

That is not it works building airplanes. You can get close to the lowest common denominator building a toaster maybe?

The point is that the graph posted by Kurfurst is what the manufacturer would like to achieve, but we all know how it goes in real life, do we? I agree that in Germany it was more strict than e.g. in Russia or Italy (:-P:-P) This is my opinion and I respect yours. But who are we? :)

[Kwiatek]

There were 2 types of engines used by LW - Db601A and DB601Aa which had little different power output.

Db 601A - sea level
1 minut emergency (2400 RPM at 1.4 Ata) - 1100 PS
5 minut emergency (2400 RPM at 1.3 Ata) - 990 PS

Db601Aa - sea level
1 minut emergency (2500 RPM at 1.45 Ata) - 1175 PS
5 minut emergency (2400 RPM at 1.35 Ata) - 1015 PS


Standart 109 E-3 with Db601 at 1.3 Ata 2400 RPM (5 minut power) reached at sea level - 467 km/h ( radiator 1/4 open)

http://www.wwiiaircraftperformance.org/me109/me109e3-1792.jpg

http://kurfurst.org/Performance_tests/109E_MP_E3_1792/WNr1792_E3_MP16feb39.html

It is good agreement with Swiss 109 E-3 Db601Aa tested with different propellers:

http://kurfurst.org/Performance_tests/109E_SwissJ347/J-347_speed.jpg

Sea level speed - 467 km/h with standart propeller

Quite close with tested captured 109 E-3 by French :

http://kurfurst.org/Performance_tests/109E_French_trials/files/vitesse_109EWNR1304.jpg

So it could be that with Db601 Aa at 1.45 Ata 2500 RPM (radiator close?) - 1 minut emergency power 109 E-3 reached 500 km/h like in German manual:

http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E_Bau_speed.png


Interesting is that at low level 109 E-3 need 5-minut power output with speed 467 km/h comparing to Spitfire MK1 at 6 1/2 lbs ( 1/2 hour limit) - 455 km/h. Db 601A had 990 HP at 1.3 Ata where Merlin III had 880 HP at 6 1/2 lbs at sea level.

[41Sqn_Stormcrow]

Well, manufacturers tend to stick with margins specified and use them, if they have the quality system giving them the ability to mangage the narrow gab. If 500km/h +/-5% on ground level was specified, I would expect the standard plane to leave the shops testified to be able to reach 475km/h, but not one km/h more.

:grin:

concerning this: I think it would have been a dangerous policy from an industrial point of view if they aimed at 475 kmh while they guaranteed 500 +/-25 kmh.

We know that during production of the plane (all parts, some coming from suppliers not under quality control of the Bayrische Flugzeugwerke) and the engine (all parts, some coming from suppliers not under quality control of Daimler-Benz) variations occur (that's why each part will have its own specs +/- acceptance margins). When all parts assembled it will lead to a performance that will vary from one plane to another. Now if they had aimed at being at the lower limit they would have ended up with planes that would not have met the specs and therefore increased the number of planes rejected by the customer. This is imho something that someone who wants to run his company profitable wants not to happen.

If one reads the chart by the French one should assume that they could have reached about 480 kmh on deck. At 500m they are at 494 kmh.

[Crumpp]

what the manufacturer would like to achieve

No it is NOT what the manufacturer would like, hope, might, or any other passive, obscure description.

As it is labeled, it is what the manufacturer guaranteed and what was accepted by the customer.

but does not say anything about the overall performance, especially top speed.

Sure it does. You do understand that these are complicated machines and they don't just roll off an assembly line into the squadron ready line.

A newly manufactured aircraft is one of the most dangerous things in aviation. It is unproven.

A very thorough inspection is completed before the first test flight. The manufacturer will put the aircraft thru a test flight period to ensure it reaches its numbers before turning it over to the customer who again goes thru their own prescribed regiment of test/inspections before accepting it.

When an airframe reaches the end of the assembly line, it was not uncommon for it to remain there for a month or so as it was tweaked and refined before being accepted.

Undercarriage tests followed before the aircraft was lowered onto its wheels and rolled out of the final assembly hall. It was then led to the firing stand to test its weapons and also for centring the compass on the rotable compass adjustment stand. After fuelling, and a last check of all functions, the engine was subjected to a test run, whereafter the Bf-109 stood ready for a works flight. In the initial test flight it was climbed to 8,000m (26,250ft), the aircraft and the engine was thoroughly checked out and performance data compared with that required. In the event that faults were found, these would be recorded and eliminated after the landing. This was then followed by a works test flight in which it could be established how many of the faults had been rectified. Where no further faults were determined on this flight, the aircraft was then release for acceptance by the BAL. In Regensbug, several pilots (Obermeier, Lohmann and others) were authorised by the RLM to carry out Bf 109 acceptance flights for the BAL. After their acceptance by the BAL, the aircraft were then taken over by the Luftwaffe.

Nest of Eagles: Messerschmitt Production and Flight-testing at Regensburg 1936-1945", de P. Schmoll, Classic Publications (2010).

[Crumpp]

There were 2 types of engines used by LW - Db601A and DB601Aa which had little different power output.

There is certainly some changes from the early 1939 data.

I really don't think development was static in Germany for 18 months before the Battle the Britain.

Otherwise we would have to believe that Germany exported more powerful engines than they used in their own aircraft. That does not make any sense and would be a first in the history of the world. :grin:

We don't know the exact conditions, perhaps it is the performance with the automatik propeller?

[Al Schlageter]

Auszüge aus Flugzeugdatenblatt (aircraft data sheet) Bf 109 E-1, E-3 nach L.Dv.556/3 @ http://www.rolfwolf.de/daten/E4/Emil.html

Motorleistungen DB601A

Kurzleistung (1 min) 1100PS bei 2400 U/min 1.4 ata

Startleistung 990PS bei 2400 U/min 1.30 ata

Steig/Kampflleistung 910PS bei 2300 U/min 1.23 ata

Volldruckhöhe 4000m

How do the speeds match for:

Höchstgeschwindigkeiten in Steig/Kampfleistung

0km - 460km/h

1km - 480km/h

2km - 500km/h

3km - 520km/h

4km - 540km/h

5km - 555km/h

6km - 555km/h

7km - 550km/h

If the Höchstzulässige Horizontal-Bodengeschwindigkeit (Maximum horizontal ground velocity) is 485km/h, how can the max speed at 0km be 500kph?

[Kwiatek]

500 km/h could be probably reached with DB601Aa motor which had 1175PS power output at sea level at 1.45 Ata 2500 RPM.

These is 75 PS more then with 601A ( 1100 PS).

Also these data above is probably for old supercharger (4.0 km FTH).

There are data where 109 E-3 reached - 467 km/h at deck - so a few km/h more, so probably also maximum speed ( at 1.4 Ata) would be little higher then 485 km/h - about 490 km/h. It could be difference in radiator position.

http://www.wwiiaircraftperformance.org/me109/me109e3-1792.jpg

These is power output with newer supercharger which rised maximum speed at FTH - with old there was 555 km/h with new one it was 570 km/h.

http://i42.tinypic.com/1zou9v8.jpg

http://kurfurst.org/Engine/DB60x/datasheets/601a1.jpg

[Robo.]

No it is NOT what the manufacturer would like, hope, might, or any other passive, obscure description.

As it is labeled, it is what the manufacturer guaranteed and what was accepted by the customer.

In perfect world: sure. In our world and especially during the war: no.

Again - 500 +- 5% means they tried to achieve 500 but it was more likely that most of the time, they made it closer to the -5% in so called real life. I am not saying that they were failing to stay within margins.

Sure it does. You do understand that these are complicated machines and they don't just roll off an assembly line into the squadron ready line.

Oh yes, please read again what I wrote before, thank you. ;)

A newly manufactured aircraft is one of the most dangerous things in aviation. It is unproven.

A very thorough inspection is completed before the first test flight. The manufacturer will put the aircraft thru a test flight period to ensure it reaches its numbers before turning it over to the customer who again goes thru their own prescribed regiment of test/inspections before accepting it.

When an airframe reaches the end of the assembly line, it was not uncommon for it to remain there for a month or so as it was tweaked and refined before being accepted.

Of course, I don't disagree at all, this is all well known facts and we can go as far as comparing the later 109 models leaving various factories. Of course there was a difference and variation in real life. The question is what data to use in order to have the a/c close to the real life performance. My opinion is that manufacturer's data should be considered as on the optimistic side.

[Crumpp]

There is certainly some changes from the early 1939 data.

I really don't think development was static in Germany for 18 months before the Battle the Britain.

If the Höchstzulässige Horizontal-Bodengeschwindigkeit (Maximum horizontal ground velocity) is 485km/h, how can the max speed at 0km be 500kph?

There are other ratings the engine was approved besides climb and combat power....

We know for a fact, C3 fuel was in use during the Battle of Britian.....

Automatik propellers (CSP) also were used during the Battle of Britian that were not in use in February 1939 as the the other data is dated.

Pick your poison....

We don't know the exact conditions, perhaps it is the performance with the automatik propeller?

[Crumpp]

My opinion is that manufacturer's data should be considered as on the optimistic side.

Noted and accepted.

For the discussion, what is your aviation experience and background. Not that your opinion is not valid, just so we all know where it is coming from.

[Kwiatek]

C3 fuel was used only in Db601N engines not in DB601.

Also automatic prop pitch for 109 E didn't change its maximum speeds.

So i think all difference at sea level speed is in radiator settings and type of engine - Db601 A or DB601 Aa which had more power at the lower alts then 601A and surly difference in tested planes.

[41Sqn_Stormcrow]

....

Quite close with tested captured 109 E-3 by French :

http://kurfurst.org/Performance_tests/109E_French_trials/files/vitesse_109EWNR1304.jpg



You all realize that the French test obtained about 494 kph at 600m altitude and in extrapolating to 0m something around 480 kph? At rpm = 2400.

The pression d'admission about 1000 (unit I cannot read). My guess is that they speak here of ATA pressure. Just not sure what kind of unit they used as I cannot decypher the scale label.

[Kwiatek]

Here is French 109 test raport :

http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

We got from French test :

With radiator open

2.5 km - 490 km/h - 2400 RPM - 960 mm. ( 1.3 Ata)
5.0 km - 520 km/h - 2400 RPM - 870 mm.


With radiator close:

5.0 km - 570 km/h - 2400 RPM - 880 mm.

There is 50 km/h difference between radiator open and close at 5 km alt.

In chart there is about 475-480 km/h at 2400 RPM at 1000 mmHg which mean that test was done at ab. 1.35 Ata - probably radiator somewhere in the middle position (looking at 5 km maxiumum speed - 550 km/h) so with higher ATA then in previous data ( 1.3 Ata - 460-467 km/h).

So it confirmed previous data for E-3

1.3 Ata

0- 460-467 km/h - depend of radiator settngs, and sort of plane

1.4 Ata (Db601A) - about 485-490 km/h

1.45 Ata (Db601Aa) - 500 km/h.

109 E-4 would be little slowier then E-3 beacuse of more draggy windscreen - it could be about 5 km/h slowier ( the same E-3 with new windscreen)

[41Sqn_Stormcrow]

The chart has at 600m a pressure of 980 mmHg pression d'admission. Extrapolating it would be at 990 mmHg at 0m. The speed is clearly close to the 480 kph when extrapolating the chart to 0m, perhaps at worst 478 kph.

5 kph velocity loss seems a bit extensive with respect to the new windscreen.

They even did not measure any difference with guns installed or not (so including the effect that for level flight higher angle of attack would have to be chosen due to increased weight of the guns).

Pression d'admission translates into inlet pressure or manifold pressure so I think this is ATA setting they used.

http://dictionary.reverso.net/french-english/pression%20d'admission

[Crumpp]

So it confirmed previous data for E-3

1.3 Ata

0- 460-467 km/h - depend of radiator settngs, and sort of plane

1.4 Ata (Db601A) - about 485-490 km/h

1.45 Ata (Db601Aa) - 500 km/h.

109 E-4 would be little slowier then E-3 beacuse of more draggy windscreen - it could be about 5 km/h slowier ( the same E-3 with new windscreen)

+/- 5%.....

[Robo.]

Noted and accepted.

For the discussion, what is your aviation experience and background. Not that your opinion is not valid, just so we all know where it is coming from.

Of course it is valid, you're extremely kind to take it in account :grin: Much appreciated.

Now tell us how do you think the E-4 performed like.

[Robo.]

+/- 5%.....

That is range of cca 50 km/h. Do you think there was a Bf 109E-4 able to fly 525 km/h under citied circumstances?

[Kwiatek]

That is range of cca 50 km/h. Do you think there was a Bf 109E-4 able to fly 525 km/h under citied circumstances?

Yea it such case E-3/E-4 would be faster then 109 F-2 which can't be true.

Try be more real.

I think 500 km/h is the highest sea level speed which could be achived by standart 109 E-3 with Db601 Aa engine and with 601A it could be even slowier ( ab. 490 km/h) with 1 minut emergency power.

[Crumpp]

Extrapolating it would be at 990 mmHg at 0m.

You are confusing manifold pressure with atmospheric pressure, I believe.

If you read the report, it says nothing about any of the data being converted to standard conditions. Therefore it is raw data for the atmospheric conditions given.

The results obtained in the Center during the first tests seem to
match well with the German manual, with regards to the level flight
speeds and the fuel consumption. Nevertheless, during the level flight
testing done under 5000 meters (external temperature = +6°C on ground
and -17°C at 5000 m.)

http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

When you convert the performance to standard conditions, the results will be faster than the raw numbers in the report.

[Robo.]

Yea it such case E-3/E-4 would be faster then 109 F-2 which can't be true.

Try be more real.

I think 500 km/h is the highest sea level speed which could be achived by standart 109 E-3 with Db601 Aa engine and with 601A it could be even slowier ( ab. 490 km/h) with 1 minut emergency power.

That is my opinion, too. I am trying to explain to Crumpp that the 500 km/h graph he's referencing as 'guaranteed' is way too optimistic.

It would be great to have actual variation in performance of certain type modelled in the sim.

[Crumpp]

Do you think there was a Bf 109E-4 able to fly 525 km/h under citied circumstances?

Sure it would be able too. All aircraft performance is a percentage range over a mean average.

Including your Bf-109F....

So some Bf-109E's were just as fast as some Bf-109F's. On average though, the Bf-109F series was the faster airplane.

Understand?

[Robo.]

You are confusing manifold pressure with atmospheric pressure, I believe.

Can you please convert 990 mmHg to ata for us please :grin:

[Crumpp]

I am trying to explain to Crumpp that the 500 km/h graph he's referencing as 'guaranteed' is way too optimistic.

You don't have to explain it to me, it is in black and white what Mtt says.

Being an experienced pilot, multiple aircraft owner, and having graduated college with a degree in Aeronautical Science, I can decide for myself what is optimistic and what is not.

Thanks! I don't feel the need to convince you one way or the other about it either. You can also decide for yourself. :) I would suggest using some scientific method or at least aviation industry standards when doing it.

[Crumpp]

Can you please convert 990 mmHg to ata for us please

About 1.28 ata....

[Robo.]

Sure it would be able too. All aircraft performance is a percentage range over a mean average.

Are we still talking about horizontal flight? :grin:

[Robo.]

You don't have to explain it to me, it is in black and white what Mtt says.

Being an experienced pilot, multiple aircraft owner, and having graduated college with a degree in Aeronautical Science, I can decide for myself what is optimistic and what is not.

Thanks!

So you asked me about my background so you can share yours? You're a very nice person Crumpp, it's a pleasure talking to you. :)

[Robo.]

About 1.28 ata....

So it probably won't be atmostperic pressure at 0m then but rather MFP. :grin:

[Crumpp]

Exactly my brother....

That French data does not appear to have been converted to standard conditions. They list the conditions though it won't be hard to convert. If someone else does not get around to it, I will do it later when I get home for you guys.

[Robo.]

Exactly my brother....

So 41Sqn_Stormcrow was not confusing MFP for atmospheric pressure as you suggested and he was basically right?

[Crumpp]

No he is not confused but he did stumble on the issue of the atmospheric conditions.

That data was taken on a colder than standard day. Breaking that down, the level speeds will be slower than standard and the climb rate will be higher than standard.

[Kwiatek]

About 1.28 ata....

990 mmHg mainfold preassure is 1.34 Ata

and

500 km/h at sea level for 109 E-3 is the best score i have seen in data (German manual). Others are less optimistic.

[Robo.]

990 mmHg mainfold preassure is 1.34 Ata

Strange, such a nice guy, experienced pilot, multiple aircraft owner who graduated college with a degree in Aeronautical Science said that was atmospheric pressure at 0m. :o

[CaptainDoggles]

Strange, such a nice guy, experienced pilot, multiple aircraft owner who graduated college with a degree in Aeronautical Science said that was atmospheric pressure at 0m. :o

Uh, I don't think that's what he said.

Pression d'admission is french for manifold pressure and it's this value that is 990 torr at sea level, not atmospheric pressure (760 torr). The 109 is supercharged, so the pressure in the intake manifold is delivered above atmospheric.

[robtek]

When i read the tenor of some the posts here, i really wonder if there would be the same energy afforded to downgrade the vmax. of the Spit Ia.

[CaptainDoggles]

When i read the tenor of some the posts here, i really wonder if there would be the same energy afforded to downgrade the vmax. of the Spit Ia.

People get emotionally invested in their favourite plane and/or its traditional adversaries.

[robtek]

Facts vs facts would be much easier, opinion vs fact or vice versa is a neverending story. :D

[41Sqn_Stormcrow]

Can you please convert 990 mmHg to ata for us please :grin:

I know a bit French and atmospheric pressure is pression atmosphèrique (et non pression d'admission comme on peut lire en bas d'echelle) - even for engineers. Perhaps with some poetic freedom they would have written pression ambiante. It is however written pression d'admission and this is a technical term. I checked and the most suitable translation are inlet pressure or manifold pressure.

See translation here:
http://dictionary.reverso.net/french-english/pression%20d'admission.

I have no clue what exactly they address here as pression d'admission and of course this is open to debate. I am however quite sure that they don't mean atmospheric pressure. Perhaps a Frenchman could tell if one is around?

EDIT: My calculator sais that 980 mmHg = 1.289 atm (=ata?)
and 990mmHg are 1.303 atm

So basically the French achieved 494 kph at 600 m with rpm 2400 and 1.303 atm pression d'admission
Extrapolating pessimistically to 0m they got 478 kph with rpm 2400 and 1.289 atm pression d'admission

[CaptainDoggles]

Perhaps a Frenchman could tell if one is around?Je ne suis pas "Francais" mais bien sur je suis Canadien. "Pression d'admission" veut dire "Manifold Pressure". Il ne fait aucun doute.

Pour "atmospheric pressure" je dirais "pression atmospherique".

EDIT: My calculator sais that 980 mmHg = 1.289 atm (=ata?)
and 990mmHg are 1.303 atm

Yep. 990 mmHg (torr) is equal to ~1.32 bar or ~1.303 atmospheres (ATA on the German gauges).

[Crumpp]

990 mmHg mainfold preassure is 1.34 Ata

Yep, I read the doc and converted 980mm. Later I confused it with the 990mm he was asking about.

Facts vs facts would be much easier,

Of course. Who cares about opinions? I have one, you have one, and everyone knows what they are like....

Facts are the engineer firm of Mtt entered into a contract to deliver the stated performance. The customer (RLM) held that firm accountable and tested each airframe delivered to ensure it met the contractual agreements in place.

Works the exact same way in today's aviation marketplace!! :)

[JtD]

pression d'admission

"Intake pressure".

1 ata is a technical atmospheres (at = technical atmosphere, a = absolut) and 1 at equals 735mm HG. Which makes 990mm 1.35 ata.

1 atm is a physical atmosphere and 1 atm equals 760 mm HG.

Some experts can't tell the two apart and come up with 1.28 ata for 980mm, which is wrong.

[Kurfürst]

500 km/h could be probably reached with DB601Aa motor which had 1175PS power output at sea level at 1.45 Ata 2500 RPM.
a
These is 75 PS more then with 601A ( 1100 PS).

Also these data above is probably for old supercharger (4.0 km FTH).

There are data where 109 E-3 reached - 467 km/h at deck - so a few km/h more, so probably also maximum speed ( at 1.4 Ata) would be little higher then 485 km/h - about 490 km/h. It could be difference in radiator position.

http://www.wwiiaircraftperformance.org/me109/me109e3-1792.jpg

Regarding the 1792 serial number Bf 109E-3 trials you posted, note the following note by the tests makers at the bottom for 467 km/h:

"These speeds has been corrected for normal (standard) temperature, and correct manifold pressure regulator settings (I guess that is the German way of saying: nominal boost) but not for the guaranteed (ie. nominal) output of the engine."

In other words, this test is for unknown power from the engine. All engines vary in output, sometimes quite considerably, and this would effect results. I would hazard to guess that the airframe may have been a poor one (remember: 500 km/h means anywhere between 475 and 525 is okay for service acceptance), and the airframe may have been a bit down on power.

Here's for example another Emil tests, showing the performance with the engine slightly down on power (developing 45 horsepower less than it should, lower figures) and corrected to nominal engine output (higher figures). This is actually the only test I've seen where anybody measured the used engine's output on a engine test bench.

With the sligthly down-on-power state for the DB 601Aa engine we have in the sim, this Bf 109E (V15a prototype actually, but its identical to the serial E-1 model), radiator 1/4 open, they got 493 km/h at 0m, and correcting the figure for the nominal full power output, 498 km/h.

http://www.kurfurst.org/Performance_tests/109E_V15a/files/109v15a_blatt6.jpg

Also 1.3ata is for the 601A-1 engine, the 500 km/h speed is understood for the slightly more potent 601Aa (though I do not believe, based on tests, that the difference would be greater than 10 kph at low level). So for an airframe just hitting the 475 km/h bottom of the acceptance limit, and having the bit less powerful 601A 467 km/h seems quite understandable.

Note though - COD seems to have choosen to model the DB 601Aa version for the Emil.

However this would represent a sub-standard aircraft. There were such, of course, but it begs the question, why would the premiere LW fighter aircraft of 1940 would be represented as a sub-par example, while RAF fighters using the performance of avarage good planes....?

Especially as the new COD engine is capable of simulating wear and such.

These is power output with newer supercharger which rised maximum speed at FTH - with old there was 555 km/h with new one it was 570 km/h.

I don't think so, the French trials of 1304 confirmed the 570 km/h top speed (and I believe it wasn't even full 1.3ata at altitude), and it is known for certain that 1304 had the old type supercharger.

[Al Schlageter]

There are other ratings the engine was approved besides climb and combat power....

We know for a fact, C3 fuel was in use during the Battle of Britian.....

Automatik propellers (CSP) also were used during the Battle of Britian that were not in use in February 1939 as the the other data is dated.

Pick your poison....

No kidding!!!:)

If the speeds for Steig/Kampfleistung (1.23ata) are not met by the game 109 then there is certainly a problem with the speed of the game 109. Speeds should be check for Start/Notleistung (1.30ata) as well.

The Bf109E-1, -3, -4 with DB601A engines DID NOT use C3 fuel. They used B4 fuel. Only 109Es with the DB601N engine used C3 fuel. C3 fuel was scarce, unlike British 100 octane fuel, and was only at certain bases. The DB601N engine was not that reliable as was the quality of the c3 fuel.

Oliver Lefevre (109 guru):

"The Speed curve which appear in the Export manual" (Yugoslavia) "seems to have been made up... Keep in mind that it was an Mtt manual not an RLM one and that it was for export."

On 1.4 ata usage

"The technical documentation is quite clear that it should not be used at high altitude, that it put some extra strain on the engine and that only in cases were take-off run was an issue should it be used. This was primarily designed for fighter/bombers and bombers carrying heavier load on take-off, keep in mind that the 109 was not the only a/c relying on the 601."

On Bf109E production numbers

"Here is the data i have based on production blocks, there is probably some innacuracy in the E-7 / E-7/N and E-7/Z department...

E-1 = 1086
E-1/B = 107
E-3 = 1406
E-4 = 250
E-4/N = 20
E-4/B = 212
E-4/BN = 15
E-5 = 29
E-6/N = 9
E-7 = 419
E-7/N = 3
E-7/Z = 17
E-8 = 60
Total = 3633"

The Russian testing was with a DB601Aa engine powered Bf109E.

[Crumpp]

So basically the French achieved 494 kph at 600 m with rpm 2400 and 1.303 atm pression d'admission
Extrapolating pessimistically to 0m they got 478 kph with rpm 2400 and 1.289 atm pression d'admission

Quick ballpark of the data to standard conditions….

478 kph TAS x 0.539956803 nautical miles at +5C = 258KTAS

We don't have a piece of the puzzle which is the atmospheric pressure for that day. I am not looking for it but if somebody finds it, I will refine the calculation.

258KTAS x 1.0299 SMOE for our density altitude Temperature difference = 265 KTAS

265KTAS / 0.539956803 = 492kph

492 kph is within 1% of Mtt stated mean of 500kph over a range of 5%.

If we had the pressure and I wasn't using some quick rules of thumb of a standard atmosphere chart but did the full calcs, I bet it would give even better agreement. The French might have had an optimistic performing Bf-109!!

The French test results give very good agreement with Mtt's published figures for the type.

[Crumpp]

"Intake pressure".

1 ata is a technical atmospheres (at = technical atmosphere, a = absolut) and 1 at equals 735mm HG. Which makes 990mm 1.35 ata.

1 atm is a physical atmosphere and 1 atm equals 760 mm HG.

Some experts can't tell the two apart and come up with 1.28 ata for 980mm, which is wrong.

Well please, read the French report and enlighten us as to what units the French are using for pressure....

If you are as smart as you think then Google French units of measure.

While the French did use metric, they had their own unique system.

http://en.wikipedia.org/wiki/Units_of_measurement_in_France

I don't know what they used but it is not the German Technical Atmosphere and the test was not flown at a 5 minute rating for the duration.

Pffft.....back to ignoring you until you have something to contribute.

[41Sqn_Stormcrow]

His reply was on a bad tone but he might be right with respect of atm being not equal to ata. I myself was not sure if atm = ata that's why I used atm for my calculation.

Unfortunately there is little information about the outdated ata but 1 at (technichal atmosphere = pressure produced by a column of 10m water) is equivalent to 735.56 torr (almost identical to 735.56 mmHg). ata is with a reference point of 0 (I assume 0m that is sea level), so this would be the pressure produced by a 10m column of water at sea level. That's what wiki told me.

I am quite sure they used the ata gauge in the plane to measure it and then translated it into mmHg.

There is one minor uncertainty with respect to the French measurement of the manifold pressure however. The mmHg values depend on the knowledge of the density of mercury. This knowledge may have evolved since ww2 so there is a slim risk that they used a different mercury density for their mmHg units. However I think there is quite a weak chance that knowledge on density of mercury evolved so much that the mmHg values would be impacted by this to the precision that is of interest here.

So basically the French obtained 494 kph at 600m with 2400 rpm and 1.346 ata.
Extrapolating pessimistically to 0m they would have obtained 478 kph at 0m with 2400 rpm and 1.332 ata.

The ingame performances are still enormously off these values.

[Crumpp]

So basically the French obtained 494 kph at 600m with 2400 rpm and 1.346 ata.

Where do get that? The French NEVER used the German technical atmosphere.

The French were instrumental in forming the ICAO in 1912 and adopting a standard atmospheric model of that organization, the ISA.

The ISA uses 760mm as 1 ATA.

Once more, the 1.28 corresponds to the 1.3 ata rating. There is NO 1.35ata rating cleared for the DB601A according to any documentation I have seen.

[Al Schlageter]

I suggest looking at this link for Pressure units http://en.wikipedia.org/wiki/Atmosphere_%28unit%29

[Crumpp]

So basically the French obtained 494 kph at 600m with 2400 rpm and 1.346 ata.
Extrapolating pessimistically to 0m they would have obtained 478 kph at 0m with 2400 rpm and 1.332 ata.

READ the report!! (You are not the only one either, I did not pay attention to some details either)

The limitations of their own instrument measurements:

Due to that, there is an uncertainity about the results. This uncertainty is about 2 to 3%. Thus maximum speed is 570km/h +/-15km/h.


The data is not converted standard conditions.

Nevertheless, during the level flight testing done under 5000 meters (external temperature = +6°C on ground
and -17°C at 5000 m.)

If you do convert it to standard conditions then the French conclusion is correct:

In general, the first tests made at the Center concerning the
Messerschmidt 109 appear to confirm the performances claimed by the
Germans.

http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

[Robo.]

Crumpp calm down dude :o

[Crumpp]

I suggest looking at this link

http://en.wikipedia.org/wiki/International_Civil_Aviation_Organization

http://en.wikipedia.org/wiki/International_Standard_Atmosphere

p0 sea level standard atmospheric pressure 101325 Pa = 760mmHg....

There is nothing that says WHAT the French used on that report so this whole line of discussion is a complete sidetrack.

[Crumpp]

Crumpp calm down dude

I am calm. I just think it is very funny that in all these discussions, the documentation gets ignored by so many and speculated upon so much.

It is what it is and the answers are written in black and white.

There is no need to guess or offer opinions. The report flatly states the data is raw and not converted to standard conditions.

It was flown at a 5 minute rating. We can speculate until the cows come home about which of the 5 minute ratings were used.

980mmHg/760mmHg = 1.289 or 1.3 ata or 1% error

990mmHg/735mmHg = 1.346 ata or 1.35ata or 1% error

It does not matter because in the end, nobody knows for sure.

It is a fact, if you convert the French data to standard conditions, it very much agrees with Mtt's published mean performance of 500kph at 0 meters with a -/+ 5% range.

[41Sqn_Stormcrow]

I dunno but you sound a bit excited.

[Al Schlageter]

There is nothing that says WHAT the French used on that report so this whole line of discussion is a complete sidetrack.

No it doesn't but it does give info on conversions.:)

[Redroach]

ata = at
1 atm = 1,0332 ata

[Crumpp]

No it doesn't but it does give info on conversions.

By all means point that out.....


http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

[Al Schlageter]

Unless the French installed there own manifold boost pressure instrument in the 109, the boost pressure used would be conversions of the German manifold boost instrument installed in all 109s, ie ata to mmHg.

[Crumpp]

12/16/39 - Finishing the aicraft setup - roundels painting.

12/18/39 - Instruments inspection by the Center`s pilot.

12/19/39 - Equipment verified during flight.
12/20/39 - (flight interrupted due to fog)

http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

They certainly could have used their own measurements. We don't know enough to determine it and any other conclusion is just a guess.

[41Sqn_Stormcrow]

Well, we might not know but we can take the most probable assumption. The chances that they would be wrong would be accordingly small.

Unless some specific clues indicating that the French were using a different transversion from ata to mmHg exist the most probable assumption would be that they used the same.

[Crumpp]

different transversion

Maybe they were not using ata at all. We don't know.

What instruments did they use? They only had a 3% instrument error which is very good.

Most bourdon tube or bellows instruments found in the panel are ~5%.

What is a fact is that the data is not converted to standard conditions.

[Robo.]

Do we know if the E-4 modelled in game has got (or is supposed to have) a DB 601 Aa engine?

The 'French test' is very interesting, but as Crumpp says, somewhat difficult to use for modelling a E-3 for the sim. The instruments are not the biggest problem really - we can still convert it back, we can also convert the whole test to 'standard day'. The issue seems to be the shape of the plane and components replaced / used, oil, glycol etc... The French apparently had a German manual to compare the outcomes with, and although the top speed was matching, there were some problems with overheating and even engine malfunction (not specified though) resulting poor climb rates when compared to the manual. It took them almost 2 minutes longer to climb to 6000m, that's a massive difference. The 50km/h difference Kwiatek pointed out might also have something to do with the overheating problems - rads were really draggy, but the 50km/h difference between fully open and fully close is rather surprising. Mind you that the difference with and without 500kg bomb was exactly the same at comparable power for a E-4/B (E-3/B), see here (http://www.beim-zeugmeister.de/zeugmeister/index.php?id=52&L=1)

Regarding the differnce between 'guaranteed' and real perofmance:

http://kurfurst.org/Performance_tests/109E_V15a/files/109v15a_blatt6.jpg

I know that's the V15a, but you get the idea why I think it would be generally unwise to modell the E-4 for CLoD after manufacturer's promises.

[CaptainDoggles]

It's not a promise it's a contract. I.e. if the aircraft doesn't meet the specifications laid out in the contract then the RLM does not accept the aircraft and it goes back to the factory.

I thought this would be a pretty straight forward idea?

[Robo.]

It's not a promise it's a contract. I.e. if the aircraft doesn't meet the specifications laid out in the contract then the RLM does not accept the aircraft and it goes back to the factory.

I thought this would be a pretty straight forward idea?

It is pretty straight forward indeed:

The contract says (regarding the top speed at the deck) 500 km/h + - 5%. Which means 475 - 525km/h. (Aa on EN ('1)) No one is saying that the manufacturer was not meeting these specifications, all I was trying to suggest was that the actual Emils were very likely to be in the 485-495 range as the real life tests + conversions suggest. Not all new machines have been test-benched and the brand new engines are unlikely to be pushed to the limits.

Is the E-4 in CLoD really (confirmed) a Aa version? Do we know what fuel we've got? Do we have any variations in FM regarding wear and tear? That would be great actualy.

[Kwiatek]

Regarding V15a performance in these test it didnt have variable-speed hydraulic supercharger control and of course it was a prototype plane ( in most cases prototypes reach better performacne then serial production planes)

Later test - French and Swiss show that tested planes had variable-speed hydraulic supercharger control with smooth speed curve but using variable hydraulic supercharger could casue some lost in speed at sea level but other hand cause more smooth speed range depend of alt without lost power between 2 speed supercharger.

So i think V15a test and performance could not be accurate for performacne of standart 109 E planes with variable speed supercharger.

Also Swiss 109 E-3 test is very accurate with German results at 1.3 Ata power at sea level speed.

http://kurfurst.org/Performance_tests/109E_MP_E3_1792/WNr1792_E3_MP16feb39.html

http://kurfurst.org/Performance_tests/109E_SwissJ347/J-347_speed.jpg

Swiss 109 E-3 reached 464 km/h with original prop ( 5 minut power) and from German test we got 467 km/h at 1.3 Ata 2400 RPM.

[Robo.]

The French might have had an optimistic performing Bf-109!!

The French test results give very good agreement with Mtt's published figures for the type.

Crumpp your calculation of 492 km/h is spot on, nice one!

Regarding the French test - it seems they had a sub-performing 109 and / or some problems with the components and fuel, olil, etc. Although the top speed figures are within limits, what do you think about the radiator drag and overall climb performance (see my previous post?) Hard to explain...

[Kwiatek]

Some time ago i made speed comparison between RL Spit MK1 +6/+12lbs (blue/red line), Hurricane MK1 +12lbs (green line) and 109 E-3 Db601Aa (black line, data from german manual 0-500 km/h , 5 - 570 km/h).

http://i56.tinypic.com/9qcrvb.jpg

[Robo.]

Regarding V15a performance in these test it didnt have variable-speed hydraulic supercharger control and of course it was a prototype plane ( in most cases prototypes reach better performacne then serial production planes)

Nice job Kwiatek, just to remind you that the V15a was identical to series E-1 and it has had some problems to reach the guaranteed power output and the difference in PS had to be calculated, hence the staggered line. In this case the prototype certainly performed worse... As for the supercharger, that's just as you wrote, the V15a had the same supercharger also, but the test was commited without it on purpose (as per the test description).

Swiss 109 E-3 reached 464 km/h with original prop and from German test we got 467 km/h.

The French test was very accurate as for the top speed, also in the same ballpark. That's for the E-3 with 601A and 9-11081A, at 1.3 ata, 0m. What was the rad setting? Also 1/4 open?

[TomcatViP]

it was not "variable" compressor. It was a step frwrd in that direction. For what I know Germans never reached tht stat of the art for multiple raisons.

As it was alrdy discussed, the French test used a damaged aircraft with cooling problem. I hve in memory that oil compatibility was also an issue (remind that those engine at the time used a lot of oil per flight hour).

The Swiss 109 were also slightly modified 109E.

It would be better guys to source the E perfs from German doc and actual flying warbird.

I remember reading the flight test of the first E3 flying in US with a 450 sea level speed at 1.2 (or was it 1.3 ?)

What ever is the right case my opinion is that you guys are wrong to try to build a super E to match the hollystic (a contracted word made out of Hollywood and mysticism ? :rolleyes:) Spit we hve in game.

I know that most of you prefer late war super banger. But BoB is all abt early war plane. So pls be patient ;)

By the way I still hve no prob to dash at 500 deck in my 109. SO I don't see what is all abt in this chating.

@Kwia : As I alrdy said those last curves you posted are complete phantasmagoria. Just look at the poor Hurri reaching it's VNE btw 7.5 to 19kft. May I suggest you to throw that one away ?

[Jumpy]

Strange, such a nice guy, experienced pilot, multiple aircraft owner who graduated college with a degree in Aeronautical Science said that was atmospheric pressure at 0m. :o

Robo, change your name to Dennis the Menace and stop picking on Crumpp.
Crumpp, give up, mate, obstinance trumps knowledge every time!;);)

[Robo.]

Robo, change your name to Dennis the Menace and stop picking on Crumpp.
Crumpp, give up, mate, obstinance trumps knowledge every time!;);)

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. ;)

TomcatViP - no, we're not trying to build an Emil that was better than the real thing. I see that many opinions and fact inetrpretations here are on the optimistic side, but as whole, we discuss this matter because we find it interesting. We don't even know it that affects anything regarding the FM. Most likely not.

French test - completely agree, but Swiss top speed was prior to the modification and seems to be legit (and interesting).

[Kwiatek]

Nice job Kwiatek, just to remind you that the V15a was identical to series E-1 and it has had some problems to reach the guaranteed power output and the difference in PS had to be calculated, hence the staggered line. In this case the prototype certainly performed worse... As for the supercharger, that's just as you wrote, the V15a had the same supercharger also, but the test was commited without it on purpose (as per the test description).

I wonder how supercharger control - variable hydraulic speed or 2 postion could affect on performacne. Surly speed curve for hydraulic is smooth without power lost between gears but other hand it could casue some lost.

In V15a chart black thick line speed was made at 1.31 Ata power output - it reached 485 km/h with radiator 1/4 open. Still we need to remember that these is prototype NOT A SERIAL PLANE with different supercharger control.

Later German test show that standart 109 E-3 with Db601A at 1.3 Ata 2400 RPM reached 467 km/h at deck with also 1/4 radiator open.

http://kurfurst.org/Performance_tests/109E_MP_E3_1792/WNr1792_E3_MP16feb39.html

So i think speed for 109 E-3 with 1-minute emergency power depend of radiator settings ( 1/4 open or close) and type of engine Db601 A or DB601Aa was in range 485-500 km/h.

[Kwiatek]

TomcatVIP for Hurricane MK1 i found 2 charts:

http://www.wwiiaircraftperformance.org/hurricane/hurricane-I-level.jpg

http://www.wwiiaircraftperformance.org/hurricane/Hurricane_Speed-HRuch.png

The second at 12 lbs line looks more reliable to me also.

[Robo.]

I wonder how supercharger control - variable hydraulic speed or 2 postion could affect on performacne. Surly speed curve for hydraulic is smooth without power lost between gears but other hand it could casue some lost.

That's not what I wrote ;). I said the V15a's engine was lacking 45PS (nothing to do with the supercharger) and the actual curve had to be calculated for guaranteed engine output. A different supercharger control would only make a difference between 2200 and 4800m, not down on the deck. The only problems mentioned (except major issue with the engine performance) was lack of manifold exhaust covers and rough finish of the engine cover.

So i think speed for 109 E-3 with 1-minute emergency power depend of radiator settings ( 1/4 open or close) and type of engine Db601 A or DB601Aa was in range 485-500 km/h.

And I agree. The Aa should behave slightly different down low and the EN rating was different, too. That's why I am asking if we really have (or suppose to have) a Aa 601 or A version.

Can you guys put a chart together with exact information (all rated ata settings, rpm, rad setting...) for both DB 601A and DB 601Aa with aproximate guestimated max TAS at the sea level?

[Kwiatek]

http://kurfurst.org/Engine/DB60x/datasheets/601a1.jpg

http://kurfurst.org/Engine/DB60x/datasheets/601Aa.jpg

[Robo.]

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.

[JG53Frankyboy]

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 ;)

[Kwiatek]

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.

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.

[Crumpp]

It's not a promise it's a contract. I.e. if the aircraft doesn't meet the specifications laid out in the contract then the RLM does not accept the aircraft and it goes back to the factory.

I thought this would be a pretty straight forward idea?

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.

The Aa should behave slightly different down low and the EN rating was different, too.

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).

Crumpp, give up, mate, obstinance trumps knowledge every time!

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.

Crumpp your calculation of 492 km/h is spot on, nice one!

It is not accurate without the pressure data.

Although the top speed figures are within limits, what do you think about the radiator drag and overall climb performance (see my previous post?) Hard to explain...

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.

[Robo.]

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.

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. ;)

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

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.

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).

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.

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.

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 not accurate without the pressure data.

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

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

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.

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.

They got worse climb results. ;)

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

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?

[Crumpp]

we can not assume automatically that the actual performance of Aa Emils was always 500km/h.

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

Just what I said, engine not quite ready

Right, we agree on it.

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.

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

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.

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.

They got worse climb results.

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.

The climbing was done at the Center with the radiators open up to 4000 m. then progressively closed until 8300m. It is possible that the different components (1) used by the German tests could permit climbing with closed radiators.

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.

[Robo.]

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?

[41Sqn_Stormcrow]

It is pretty straight forward indeed:

The contract says (regarding the top speed at the deck) 500 km/h + - 5%. Which means 475 - 525km/h. (Aa on EN ('1)) No one is saying that the manufacturer was not meeting these specifications, all I was trying to suggest was that the actual Emils were very likely to be in the 485-495 range as the real life tests + conversions suggest. Not all new machines have been test-benched and the brand new engines are unlikely to be pushed to the limits.

Is the E-4 in CLoD really (confirmed) a Aa version? Do we know what fuel we've got? Do we have any variations in FM regarding wear and tear? That would be great actualy.

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'.

[Bewolf]

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?

[Robo.]

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

[41Sqn_Stormcrow]

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.

[Crumpp]

The manufacturer's specification of 500 kmh +/-25kmh does definitely not mean that the 109 reached 500 kmh but probably something less.

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

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.

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

Here:

http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

[Robo.]

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

Here:

http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.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.

[Crumpp]

That is the Yugoslavian test

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.

Reproduction of pages 48 - 53 from Baubeschreibung für das Flugzeugmuster Messerschmitt Me 109 mit DB 601, from circa 1939. The date cannot be positively identified, however, the Yugoslavian translation of the manual, probably shipped along with the Yugoslavian export Bf 109Es, and which is otherwise identical to the German, is dated 1940.

There is no mention of the aircraft actualy achieving 500km/h, at least I can not see it anywhere.

Sure there is:

Die Flugdauer bei Vollgasflug beträgt 1,1 h in 6000 m.
Bei entsprechender Drosselung erhöht sich die Flugzeit bis
auf zwei Stunden.

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

http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

[Crumpp]

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.

[CaptainDoggles]

For those not familiar with the math:

http://mit.edu/16.unified/www/FALL/thermodynamics/notes/node97.html

[41Sqn_Stormcrow]

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_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

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

[JtD]

Die Flugdauer bei Vollgasflug beträgt 1,1 h in 6000 m.
Bei entsprechender Drosselung erhöht sich die Flugzeit bis
auf zwei Stunden.
They flew at full power for 1.1hours, to altitudes of 6000m, and the total flight lasted 2 hours.

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".

[Robo.]

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.

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.

Sure there is:

'Die Flugdauer bei Vollgasflug beträgt 1,1 h in 6000 m.
Bei entsprechender Drosselung erhöht sich die Flugzeit bis
auf zwei Stunden.'

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

http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

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

[Robo.]

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.

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

[Crumpp]

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

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?

[Robo.]

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.

[CaptainDoggles]

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.

[Jumpy]

[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.

[CWMV]

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

[CaptainDoggles]

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

(I always have trouble spelling 'maneouvre' - if it is wrong I,m sure you will be kind enough to correct me.Maneuver (US) and Manoeuvre (Commonwealth) are the two spellings, I think.

[Jumpy]

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.

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

[Crumpp]

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

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

[CaptainDoggles]

Fighting was never my strong suit

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

In Pursuit (http://web.comhem.se/~u85627360/inpursuit.pdf)

Fighter Combat: Tactics and Maneuvering (http://www.amazon.ca/Fighter-Combat-Maneuvering-Robert-Shaw/dp/0870210599)

And I'd also recommend posting threads in the gameplay forum (http://forum.1cpublishing.eu/forumdisplay.php?f=197) if you want help or have specific questions.

[robtek]

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.

[41Sqn_Stormcrow]

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.

[Robo.]

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.


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.

[Robo.]

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

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).

[Robo.]

Fighter Combat: Tactics and Maneuvering (http://www.amazon.ca/Fighter-Combat-Maneuvering-Robert-Shaw/dp/0870210599)

I agree, this book is a gem.

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

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:

[41Sqn_Stormcrow]

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.

[robtek]

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.

[CaptainDoggles]

There is no disagreement at all. :o As you say, manufacturer calculated speeds in certain conditions, but he never verified them with flight tests.

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.

The main reason being it was not really possible, the data are simply theoretical speeds.

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.

but these speeds never achieved in any actual empirical tests (again, various reasons).

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.

[Kurfürst]

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_tests/109G_Erlatrials/Erla109G_13speedrun_scatter_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.

[bugmenot]

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.




There's typo in the Baubeschreibung: M o t o r l e i s t u n g
http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

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

http://img133.imagevenue.com/initial/loc239/45525_DB601Aa__Motorleistung.jpg

[Robo.]

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

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.

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.

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 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.

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?

[Robo.]

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

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.

[Robo.]

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.

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.

[Robo.]

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

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

[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 :rolleyes:

[Robo.]

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.

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.

We have exactly that aircraft modelled in the sim, so E-1, E-3 and E-4 should satisfy these specs.

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. ;)

[CaptainDoggles]

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.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.


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.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.

[41Sqn_Stormcrow]

?
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]

?
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.

[41Sqn_Stormcrow]

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.

[Robo.]

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.

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?

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.

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

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.

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.

[Robo.]

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]

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.

[41Sqn_Stormcrow]

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]

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.

[41Sqn_Stormcrow]

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.]

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! :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?

[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.

[41Sqn_Stormcrow]

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.

[Robo.]

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.]

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. :o

[TomcatViP]

...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.

[41Sqn_Stormcrow]

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:evil:

[JG53Frankyboy]

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.

[Robo.]

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.

I hope so ;)

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.

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?

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.

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.

This is boring:evil:

Don't read it then dude ;)

[TomcatViP]

This is not a history book with a figure, this is a flight sim.


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 ... ;)

[robtek]

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.

[Robo.]

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?

[robtek]

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

[CaptainDoggles]

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.