Spit IX vs XIV vs 109K

[ATAG_Flare]

For those who think the Spit IX won't have a chance against the 109K even with +25lbs Boost, here's what I found out on www.spitfireperformance.com . The IX is sure slower than the XIV and the Kurfurst but in climb-rate the LF.IX (The one coming to DCS) can out-climb the 109K at almost all altitudes even with just +18lbs boost.

I put the IX data on the XIV vs 109K graphs for easy comparison.

http://i.imgur.com/ExkT8Sr.jpg
Climb

http://i.imgur.com/Na9nONU.jpg
Speed


Flare

[macnihilist]

Well, I don't want to turn this thread into a discussion about the reliability of sites like spitfireperformance.com or kurfurst.org, but it should be mentioned that many people think spitperf.com has a certain bias in its presentation and its selection of sources.
(That is not to say the graphs are wrong, but people should probably check them against other sources.)

[Foul Ole Ron]

I'd be dubious about a mid '43 model Spit being able to out-climb a late '44 model K-4. I'm not an expert on the 109 at all but it sounds like that while the K-4 wasn't the maneuverable fighter earlier 109 versions were it was both fast and could climb like a demon. I think the Spit IX will struggle against the K-4 which is only natural as there's ~1.5 years operational deployment between them which is a very long time. A Spit IX would more likely have bumped up against a G-6 or G-10.

[hnbdgr]

Yes, you need to tread carefully with both sources.

Just an example: spit1a vs 109E comparison is contradictory to itself. http://www.spitfireperformance.com/spit1vrs109e.html

On this chart, we can see different values for the spit (+6.25 +12 boost) and 109-E1 + 109-E3

http://www.spitfireperformance.com/spit1-109espeed-blue2.jpg

From these values we see the spit +6.25 is the slowest one of the lot (on the deck). Yet the author states: "The Spitfire proved to be considerably the faster of the two, both in acceleration and straight and level flight, without having to make use of the emergency +12 boost."

This is backed up by a single example from a test of a captured 109:

http://www.spitfireperformance.com/spitfire-I-me109e-rae-comptrials.jpg


So the author uses as his example: a single captured fighter, using slightly different fuel, flown by a RAE test pilot - we don't know what condition the engine was in, how the ground rudder trimmer was set for, what elevator trim the pilot used and whether he used the 1.4 takeoff ATA, etc.

All in all the website make it look like the 109 was considerably poorer in performance compared even with the non-boosted spitfires when the chart he gives at the beginning says the opposite.

The only measured 109E data from Germany give about 467(E3 (http://www.wwiiaircraftperformance.org/me109/me109e3-1792.jpg)) and 476(E1) (http://www.wwiiaircraftperformance.org/me109/Me-109E1-1791.jpg) kmh. This is still faster then the max measured speed of a spit with 6.25 boost of 283mph (455.5 kmh) - all values at sea level.

15414

So, it must be cross-referenced with other sources and not just taken at face value. For what it's worth, there is a lot of valuable info on that site!

[gavagai]

Nothing is going to outclimb the 109K-4 as it stands right now. Yo-yo already confirmed that it climbs too well and the FM needs more work!:stunned:

[RAF74_Buzzsaw]

Well, I don't want to turn this thread into a discussion about the reliability of sites like spitfireperformance.com or kurfurst.org, but it should be mentioned that many people think spitperf.com has a certain bias in its presentation and its selection of sources.
(That is not to say the graphs are wrong, but people should probably check them against other sources.)

There is absolutely no comparison between http://www.wwiiaircraftperformance.org/ and other sites... it is hands down the best site for WWII aircraft performance site on the internet by far.

Negative comments re. the site generated graphs etc. and their occasional comparisons are a red herring... the raw original data which makes up the majority of the site content is superior to anything available anywhere else.

If you don't like the site comparisons, then just look at the original data. This data is contributed by people in any number of countries, not just Britain.

Is the site complete? No, I have some material which they don't have, others I know have other material, but the site also comes up with new material all the time which is new and useful.

It is not by any standard I have seen 'biased'... the material is presented for anyone to look at and make their own decisions. The owners of the site have their opinions in certain areas... but they don't prevent others from looking at the raw sources. I don't always agree with some of their comparison articles, but that does not mean they can be called biased. Like any scholarly inquiry, based on data gathered a 1/2 century previously, there is room for multiple opinions.

[macnihilist]

Fair enough. Personally, I haven't made up my mind yet; neither do I know enough about aircraft performance, nor did I look at the site long enough to come to a conclusion.

But I have to say one thing: If I see a comparison article like their "SpitI vs. 109E", where the vast majority of references consists of stories of surviving(!) British pilots and British test reports from a time when the pendulum could very well have swung in both directions and any boost in morale was welcome, I smell selection bias. Even if that is the best that is possible with today's sources (which, to be honest, I doubt), I can understand people who are skeptical about the site.


Returning to the original topic: I cannot see the climb curve for the Spit IX in the first image now, but if the Spit LF IX with 18 boost could outclimb the 109K4 with 1.8ata+MW50 at almost all altitudes, not just at low level, I'm curios how it did this. Was lighter or did it have more lift or was it something else? (And no, this is not some kind of saucy trick question, I really want to know.)

EDIT: D'oh! Now I see it, black is blue. Still, the questions remains.

[Karaya]

But I have to say one thing: If I see a comparison article like their "SpitI vs. 109E", where the vast majority of references consists of stories of surviving(!) British pilots and British test reports from a time when the pendulum could very well have swung in both directions and any boost in morale was welcome, I smell selection bias. Even if that is the best that is possible with today's sources (which, to be honest, I doubt), I can understand people who are skeptical about the site.

I tend to agree here though I dont want to imply bias right away. The performance sheets for the captured Bf109Es do lack some vital information regarding engine performance at the time and radiator settings used. From looking at the various tests the "Vollgashorizontalflüge, Meßprotokoll vom 26.4.38, B.F.W. Augsburg" and "French Figures Me 109 E" seem the most consistent and well documented. As can be seen from the french trials the radiator position has a huge influence on the attained air speed and by closing the rads the French were able to reach ~570kmh at 5000m which matches the German figures. The latter you have to keep in mind that the engine was stated to not attain full power thus the included "Garantieleistung" graph which is to show projected performance at the engine power level guaranteed by the manufacturer (Daimler Benz).

I do wonder why the comparison is completely hush about the poor aileron control on the Spitfire below 300mph and only states that both fighters are similarly handicapped at 400mph - a speed that both aircraft can only attain in a dive.

[hnbdgr]

I'd like to ask something here... I have seen the "Garantieleistung" mentioned in the messprotokols as well, but I'm still not unsure what it is.

Is it so to speak an ideal output of the engine or is it maximum output under 1.4 ATA? What really is garantieleistung? If the performance was guaranteed - what is the guaranteed figure of max speed for a 109E1 or E3 at sea level?

[Karaya]

I'd like to ask something here... I have seen the "Garantieleistung" mentioned in the messprotokols as well, but I'm still not unsure what it is.

Is it so to speak an ideal output of the engine or is it maximum output under 1.4 ATA? What really is garantieleistung? If the performance was guaranteed - what is the guaranteed figure of max speed for a 109E1 or E3 at sea level?

Garantieleistung = guaranteed performance by the manufacturer

As said, the engine was found to be underperforming, therefore the aircraft performance (besides the actual recorded) was calculated for a properly working one. The estimated performance is shown in the graph.

[hnbdgr]

Yes, but is garantierleistung actually ever measured or is it just a term for something else, like "at ideal conditions". I mean I know Garantierleistung says it's guaranteed but I can't find the guaranteed values measured anywhere. Let's look at this:

15493

Which closely corresponds with this:

15494

The problem is neither seems to be an actual measured value. First one is just a calculated/supposed value and the second one is not from a test, rather part of a manual - can't remember if it was for an export version or not. (albeit, I would take issue with it being called "nazi propaganda" as it's called on the website)

Next, I've had a closer look at this:

15495

It's true, the speed difference between French measurements with radiator flaps closed and open is quite large, although the line with rads closed doesn't extend to sea level - one could argue it would begin somewhere at 475kmh which is roughly what we have now in game.

There is only one rather confusing graph that shows near 500kmh (which should be close to the garantierleistung) and that's this:

15496

On the right hand we have 2 curves, IAS and TAS. At sea level, IAS begins at around 500, but TAS is given as 450...!? They cross at 1500m.... I don't understand this, every IAS TAS chart I saw begins with IAS/TAS being equal.... can somebody explain?

So if the guaranteed performance was near 500kmh - it's not measured anywhere, neither is it the case in game (game values are around 475 which is correct imo).

To touch on 109vsSpit comparison and the lack of comments on ailerons, I'd say it's a good example on subjective approach the author takes. In short, the website is great for raw data, but the comments and how this data is presented (or which data gets presented and which doesn't) to the reader, sometimes don't tell the whole story.

[Karaya]

http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html


Notes on the engine :

The 109E was produced with at least two major models of the DB 601A engine (DB 601N model was also used, but is not detailed here):

the A-1, with 1,30 ata manifold pressure for 990 PS output at 0m, and
the Aa, with 1,35 ata manifold pressure for 1045 PS output at 0m, both for cleared for 5 minute periods.

It should be also noted that the D.(Luft) T.3601, DB 601 A Motoren-Handbuch also notes that slightly higher manifold pressures up to +0,03 ata are normal under some circumstances; it also notes +/- 2,5% tolerence on output. During the trials, the engine, referred to simply as 'DB 601A', developed 1,31-1,33 ata and 951 PS (Blatt 6). The 996 PS nominal output indicated by the report points to the use of a DB 601A-1 engine.

The DB 601A engine was bench-tested before the trials and it was found that it was not developing full power guaranteed by the engine manufacturer, but only 951 PS instead of the 996 PS as indicated on the engine curves (value corrected for test conditions in the report), thus claims that the V15a prototype was operating in excess of the established operational limits of the DB 601A are baseless.

It appears that variable-speed hydraulic supercharger control was either not present or not engaged in the tests (ie. testing seperately with both supercharger gears) : low-altitude and high-altitude supercharger speeds were engaged at a given boost pressure, therefore the curves do not show the characteristic shape of the DB power curve - this would result in a more smooth,curved transition and improved in performance between the supercharger`s two critical altitudes (ca between 2200 and 4800m) in level flight.

Corrected performance for guaranteed engine output, as well as for the correct manifold pressure regulator settings is shown with staggered line marked Garantieleistung. Performance at the guaranteed nominal output was thus 498 km/h at 0 m, and 572 km/h at 4800 m.

The first graph that shows two curves of which one is at Garantieleistung shows data from an actual test flight as detailed above. I dont understand why you keep hanging yourself with the term Garantieleistung - it is exactly what it says!

The french trial is detailed here:
http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

Extrapolating the topspeed for closed radiator down to sea level the respective speed would come in somewhere around 480kmh which for a non-factory-fresh machine after more or less abuse is fairyl good.

[ATAG_NakedSquirrel]

Not to throw fuel into the already complicated fire, but one thing I notice when flying DCS K-4(beta) vs CloD is the slats.

A bit of a disclaimer. I don't have a force feedback joystick. But with CloD I seem to notice a difference in performance when flying on the edge of slat deployment in the 109. (especially the light 109-E) However, in DCS (and BOS if anyone cares) I really don't notice if the slats are deployed or not.

I know this is anecdotal. I dont know if it is "correct" or not. But it's something I've noticed with CloD. I "feel" something is different, and I'll look over to the wings and notice the slats deployed. It feels like something is different with the plane, even without FFB. I hope something like that is added to DCS, because currently, I don't notice the slats being deployed, and they don't seem to matter one bit if they are out or not, and there certainly don't seem to be any cues, other than the 3d model having the slats out.

My only example would be this dogfight from a while ago:

(this was the previous version of the TF patch btw, so the FM of the aircraft are different now)

https://www.youtube.com/watch?v=vToXgzPPTyk

I know it's not a great visual example, but I could feel the slats 'pop' out in turns. You can see me constantly looking over at my wings when I am trying to keep a steady, no buffet turn. One thing I remember about this dogfight in particular (Since I was climb turning at the very edge of slat deployment) is that I had a hunch when my slats popped out. Also, I had enough advantage that I could test the waters (so to speak) and try turning with slats, but it quickly looked like I was losing ground.

To be fair, I don't feel it as much in the E-4 or N's as I do in the E-1, so perhaps something as late war as a K4 has such a large power to weight ratio, that the slats aren't noticeable, but I find it an interesting difference none the less. Also, DCS seems to have less cues for drag. There is a bit more head bob and tilt for G's, but I often get 'lost' when I deploy flaps. Especially for the P51. I'll think I have one or two notches of flaps deployed, and I look to my wing and I see I almost have a full set of landing flaps (but then again, maybe DCS is giving me cues I'm not picking up).

I'm not siding either way on this, but I find it interesting and thought I would share.

At any rate, I plan to fly all three planes and murder you all in your sleep with it anyway :devilish:

:shoot:

(because god knows I won't win in a fair dogfight! :salute:)

[hnbdgr]

http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html



The first graph that shows two curves of which one is at Garantieleistung shows data from an actual test flight as detailed above. I dont understand why you keep hanging yourself with the term Garantieleistung - it is exactly what it says!

The french trial is detailed here:
http://kurfurst.org/Performance_tests/109E_French_trials/french_109e_performanceT.html

Extrapolating the topspeed for closed radiator down to sea level the respective speed would come in somewhere around 480kmh which for a non-factory-fresh machine after more or less abuse is fairyl good.


Ok, it is what it says it is. It still leaves us with no actual measured values. Just extrapolated values(guesswork) in the case of the french test and also corrected values in case of blatt 6 - unless the dotted line is an actual measured result.

In contrast here are some actual values:

http://www.wwiiaircraftperformance.org/me109/Me-109E1-1791.jpg

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

You will notice they say "jedoch nicht auf garantieleistung umgerechnet". So why is measuring of the value provided by garantieleistung so elusive? I'm not taking sides here, just trying to get my head round these charts that's all.


Also what is happening in that strange graph that shows IAS values at 500, but TAS at 450?

[Gromit]

Problem you have with all these tests results is they were done by different bodies, each with their own testing methods with different parameters and calculations.
every time you see an allied test of an axis aircraft and the results are below what you expect the "engines underperforming" cliché gets trotted out, fact is these are captured frontline aircraft, some were repaired, others as found.

if they are frontline aircraft you are going to get different results from a factory fresh aircraft, wear and tear makes a considerable difference to an aircrafts performance, just read through allied tests of various aircraft of their own and you will find different results from different aircraft of the same type, there is no gold standard as build quality variations must be considered and trotting out absolute highest figures is disingenuous at best!

if the allies test a captured frontline aircraft then that's representative of an aircraft that's been used and should give an average result for a used aircraft, no squadron takes off with a brand new aircraft for each sortie!

And if you think this is confusing, try extrapolating logical and consistent data from armour penetration charts for anti tank guns, every damn ordnance dept of every damn nation used different parameters, it's a minefield!

[9./JG52 Ziegler]

Problem you have with all these tests results is they were done by different bodies, each with their own testing methods with different parameters and calculations.
every time you see an allied test of an axis aircraft and the results are below what you expect the "engines underperforming" cliché gets trotted out, fact is these are captured frontline aircraft, some were repaired, others as found.

if they are frontline aircraft you are going to get different results from a factory fresh aircraft, wear and tear makes a considerable difference to an aircrafts performance, just read through allied tests of various aircraft of their own and you will find different results from different aircraft of the same type, there is no gold standard as build quality variations must be considered and trotting out absolute highest figures is disingenuous at best!

if the allies test a captured frontline aircraft then that's representative of an aircraft that's been used and should give an average result for a used aircraft, no squadron takes off with a brand new aircraft for each sortie!

And if you think this is confusing, try extrapolating logical and consistent data from armour penetration charts for anti tank guns, every damn ordnance dept of every damn nation used different parameters, it's a minefield!

Agreed Gromit. Engines in particular will vary (as any builder knows) due to time (SMOH). A brand new engine will not develope full power until it is "broken in" a bit. So there is always going to be some question as to numbers and all one can do is take as many examples as possible and average out these questions.

[hnbdgr]

Exactly and here i think TF's approach is quite fair in evaluating the numbers.

[RAF74_Buzzsaw]

TF rates data on the following level of authority from most reliable to least:

1) Manufacturer's Factory test, Owning Airforce test, or in the case of the US types, NACA test of US manufactured type

2) NACA test of non-US manufactured type, other Airforce test of non-national manufactured type

3) Test of captured aircraft by opposing side Airforce

In addition, tests are rated on the level of complexity of the measuring instruments... obviously tests with reports by the 'seat of the pants' impressions of the flying pilot are much less reliable than measurements done with specifically fitted and calibrated measurement devices.

[Karaya]

That sounds very reasonable!

[VO101_Kurfurst]

Fair enough. Personally, I haven't made up my mind yet; neither do I know enough about aircraft performance, nor did I look at the site long enough to come to a conclusion.

The raw data is good and plentiful - credit to the many people who have researched it - but at times, particularly when the numbers 1, 0 and 9 are involved, curiously become somewhat incomplete, which appears to be in line with the personal preference of the editor himself. ;)

Subjective interpretation is one thing, selection bias, as you noted, is another. I don't suppose that the selection if British memoirs falls into this, though, simply it is they are far more readily available (especially if the editor does not speak German at all). To me, they are interesting as the human side of the story, not necessarily very revealing on the subject of performance, tactics or strategy any more than a listing of Galland 104 victory claims would be. The one who happened to zap the other guy was usually the only one who could wrote a story about it.


Returning to the original topic: I cannot see the climb curve for the Spit IX in the first image now, but if the Spit LF IX with 18 boost could outclimb the 109K4 with 1.8ata+MW50 at almost all altitudes, not just at low level, I'm curios how it did this. Was lighter or did it have more lift or was it something else? (And no, this is not some kind of saucy trick question, I really want to know.)

Well, a couple of reasons I can think of..

1, Lighter wingload of the Spit
2, The Ks propellor was not evidendltly optimized for for climb
3, The K in the graph being an 1.8ata variant
4, The Spit in the graph strikes me as BS 543 the first testbed for Merlin 66 in spring 1943, and this aircraft had evident issues with (too rich) mixture that appears to have been deviating from normal settings - boosting low/medium performance (good) but you can see the very odd fall off at high altitudes, and an abnormal 'break' in the curves, which decreased top ceiling (bad) - it would appear the trials were re-done later with a properly configured Spit, BS 310.
5. Its always very largely influenced by radiator flap settings on both planes.

In any case, given serial production variations, I would say the IXLF and the K-4 climb more or less the same at low speeds - the main advantage for the K is of course, speed, and it can exploit this by slowly climbing away at high speed.

[VO101_Kurfurst]

Yes, but is garantierleistung actually ever measured or is it just a term for something else, like "at ideal conditions". I mean I know Garantierleistung says it's guaranteed but I can't find the guaranteed values measured anywhere. Let's look at this:

15493

Which closely corresponds with this:

15494

The problem is neither seems to be an actual measured value. First one is just a calculated/supposed value and the second one is not from a test, rather part of a manual - can't remember if it was for an export version or not. (albeit, I would take issue with it being called "nazi propaganda" as it's called on the website)

Guraranteeleisting is just that, the performance the manufacturer (Messerschmitt, Daimler Benz, Supermarine, R-R) guarantees in the contract for the product (109, DB 601, Spitfire, Merlin), within certain specified tolerance limits. Tolerance specs are needed because we speak of mass produced planes, engines, and no two will be exactly the same. A product that do not meet the contracted specs upon handover inspection (in Germany, this was conducted with test flight by the Luftwaffe's BAL organisation) are faulty deliveries. The manufacterer won't get a penny or pfenning from the customer them until they are fixed.

The first one is actually a measurement by Messerschmitt on the 109E prototype, that matched the later serial production planes in everything AFAIK. Low altitude speeds were measured by four-way speed runs over known distance, so there is practically zero measurement error involved. The is the left curve.

The right curve is a correction for nominal (guaranteed) engine performance, because the particular engine used in the test was bench tested, and was found to be down a bit in power, iirc developing only 1.31/1.33 ata instead of a steady 1.35ata boost, developing 45 PS less than it should. So they corrected the measured data to reflect when the same plane would be flown with an engine producing the exact same horsepower as is written on the engine spec sheet (again subject to production tolerances, wear etc.). Its all noted in the reports notes, which are on my site in full, albeit in German.


The second graph you linked is from the official Me 109E type specification sheet ("Nazi propaganda" :D ) from Messerschmitt (it appears to be for 601Aa engined planes), very likely based on the results of the first paper, and which Messerschmitt AG, Augsburg, guaranteed to be reachable with every single serial production plane within +/- 5% tolerance that is bought by any customer, be it the Luftwaffe or the Swiss or Yugoslavian Air Force. If not, then Messerschmitt AG, Augsburg has delivered a faulty product and shall not be eligible for 45 000 Imperial Marks after each plane (and usually several times of that if the plane was going for export). There was no point of lying.

[macnihilist]

Subjective interpretation is one thing, selection bias, as you noted, is another. I don't suppose that the selection if British memoirs falls into this, though, simply it is they are far more readily available (especially if the editor does not speak German at all). To me, they are interesting as the human side of the story, not necessarily very revealing on the subject of performance, tactics or strategy any more than a listing of Galland 104 victory claims would be. The one who happened to zap the other guy was usually the only one who could wrote a story about it.

Just a small clarification: I meant selection bias in the statistical sense, not necessarily implying purpose or agenda. It's basically what you said: we only hear the stories of the survivors, mostly British ones, and I expect that to produce a somewhat skewed account of things. The same is true for the test reports: we mostly hear one side of the story.



Well, a couple of reasons I can think of..

1, Lighter wingload of the Spit
2, The Ks propellor was not evidendltly optimized for for climb
3, The K in the graph being an 1.8ata variant
4, The Spit in the graph strikes me as BS 543 the first testbed for Merlin 66 in spring 1943, and this aircraft had evident issues with (too rich) mixture that appears to have been deviating from normal settings - boosting low/medium performance (good) but you can see the very odd fall off at high altitudes, and an abnormal 'break' in the curves, which decreased top ceiling (bad) - it would appear the trials were re-done later with a properly configured Spit, BS 310.
5. Its always very largely influenced by radiator flap settings on both planes.

In any case, given serial production variations, I would say the IXLF and the K-4 climb more or less the same at low speeds - the main advantage for the K is of course, speed, and it can exploit this by slowly climbing away at high speed.

Some interesting points, thanks!

[hnbdgr]

Guraranteeleisting is just that, the performance the manufacturer (Messerschmitt, Daimler Benz, Supermarine, R-R) guarantees in the contract for the product (109, DB 601, Spitfire, Merlin), within certain specified tolerance limits. Tolerance specs are needed because we speak of mass produced planes, engines, and no two will be exactly the same. A product that do not meet the contracted specs upon handover inspection (in Germany, this was conducted with test flight by the Luftwaffe's BAL organisation) are faulty deliveries. The manufacterer won't get a penny or pfenning from the customer them until they are fixed.

The first one is actually a measurement by Messerschmitt on the 109E prototype, that matched the later serial production planes in everything AFAIK. Low altitude speeds were measured by four-way speed runs over known distance, so there is practically zero measurement error involved. The is the left curve.

The right curve is a correction for nominal (guaranteed) engine performance, because the particular engine used in the test was bench tested, and was found to be down a bit in power, iirc developing only 1.31/1.33 ata instead of a steady 1.35ata boost, developing 45 PS less than it should. So they corrected the measured data to reflect when the same plane would be flown with an engine producing the exact same horsepower as is written on the engine spec sheet (again subject to production tolerances, wear etc.). Its all noted in the reports notes, which are on my site in full, albeit in German.


The second graph you linked is from the official Me 109E type specification sheet ("Nazi propaganda" :D ) from Messerschmitt (it appears to be for 601Aa engined planes), very likely based on the results of the first paper, and which Messerschmitt AG, Augsburg, guaranteed to be reachable with every single serial production plane within +/- 5% tolerance that is bought by any customer, be it the Luftwaffe or the Swiss or Yugoslavian Air Force. If not, then Messerschmitt AG, Augsburg has delivered a faulty product and shall not be eligible for 45 000 Imperial Marks after each plane (and usually several times of that if the plane was going for export). There was no point of lying.

Thank you I appreciate you contributing here. :thumbsup: I think I understand what you're saying. Guaranteed performance was supposed to give you 500kmh +/- 5% (25kmh).

I'm playing the devils advocate here and my question is: Is there a measured (not calculated) value in existence of a me-109E 1-4 (prototype or serial production) that shows it's max speed at sea level anywhere between 500-525 kmh?

If I'm explaining this graph right then perhaps I've answered my own question:

15610

The third line I assume to be max speed and that is 322 mph / 518 kmh which is a displaced(calculated?) value and it's displaced from (I assume) an orginal measured value of 310mph/498kmh (as it says displaced by 12miles ?) It looks as the speed there is TAS. That would be 498kmh at SL which is close enough to 500kmh


And my bonus question is what is the deal between IAS/TAS crossing at 1.5 km and not starting at same altitude(SL) on this graph:

15609

Many thanks, hope my questions are sensible :salute:

[RAF74_Buzzsaw]

Everyone should understand aircraft designers are continually working with tradeoffs...

So for example, in the area of top speed versus climb.

A propellor optimized for top speed will not deliver an optimal climb rate, and vice versa.

Take a look at the Swiss tests of the 109E for an example... in that instance the Swiss Air Force is deciding which compromise they prefer of the three propellors.

There are literally dozens of different prop tests for the Spitfire IA, all of which result in different top speeds/climbrates. The same applies for nearly all combat types in the war... the P-47 initially had a lot of problems with a poor climbrate... till the paddle blade types were developed for it... but those props, while giving a considerably improved climb, also reduced top speed.

Some advocates for a particular aircraft want to have both the optimum climbrate achieved with a given prop, as well as the optimum speed achieved with a different prop... that is a no go as far as I'm concerned.

[Chuck_Owl]

There is an interesting thread here, Buzzsaw... What do you think?

http://forum.il2sturmovik.com/topic/14609-why-i-still-dislike-il-2-clod-bf109-pilot/


myfabi94, on 15 Feb 2015 - 07:10, said:
I am a Bf109 fan, and as such was greatly interested in CloD in the beginning. As the game was utter [Edited], as was my PC and so I didn't play until a couple of months ago, unitl I got my new Laptop, which runs the TF mod smoothly.
So I did a couple of test flights all on my own, getting to know her, and she was nothing like I expected her, especially when compared to the Spitfire. I knew that the Spitifre should be lighter and easier to fly at high speeds but roughly equal when slower. I also knew that the Bf109 should have better roll speed at low speeds, and inferior at the dive limit.
So, disappointed as I was I read up, trying to find where the Bf109 was so clearly inferior to the Spitfire, and I didn't find anything.
And it seemed more and more that apparently the Bf109E ingame was built entirely around british opinions and results and therefore biased.
And even then it still is worse than even the british tried to show in their tests.

I tested the Bf109 stall and compared it to british results by Eric Brown: "Both rudder and ailerons are effective right down to the stall, which is very gentle, the wing only falling about 10 degrees and the nose falling with it. There is no tendency to spin."
and: "In this respect the Bf.109E scores by its excellent control near the stall and innocuous behaviour at the stall, giving the pilot confidence to get the last ounce out of his airplanes turning performance."
RAF Royal Aircraft Establishment (RAE) Farnborough handling trials,Bf.109E Wn: 1304.

In my tests it spins violently and will not recover unless acted against with addition of full engine power and countering the spin with ailerons and rudder. Spin behavior of the aircraft is definetly far worse than even the british claimed it to be. The aircraft dips the wing and then does a half clockswise roll after which the nose points straight down, with a tendency to spin uncontrollably unless acted against using aileron, elevator and rudder input after to complete spins at least, often more.
In british testing spin recovery would be done by centering the controls.

Concerning the high control forces the simple argument of different standards of physical exercise and what Pilots were used to is vital too. British testers found the Bf109 way to heavy on the controls, while german testers found the britsh controls too light for save manouvering as the light forces would cause them to blackout or overstress the aircraft.

"- This give an important clue why there is very large differencies in opinion about the heaviness of the 109. In high speeds the plane stiffened - but 109 pilots could still control if. So why the Allied test pilots have so different opinion? Simple. They were not used to the plane. Many of them had flown planes, that had for example hydraulically enhanced controls. Or had flown other types, that had very different feeling. Real 109 pilots on the other hands were used to the heaviness - and practised according to it. Although the high control forces were undoubtedly an undesirable feature, or a problem, restricting the manoeuvrability of the aircraft, especially at high speeds, they were perhaps partly compensated by the emphasis put on physical exercise in the Luftwaffe and FinAF. Numerous accounts by pilots of those forces mention the amount of exercise and sports conducted by the aircrew. Daily physical training might be mandatory, depending on your unit. And every flight was practically a work out session, given the admittably heavier control forces of 109 in higher speeds. It is easy to see how the Me 109 pilots flying it regularly were markedly more adapted to its requirements than a pilot who was only flying limited number of test sorties." The Author of http://www.virtualpilots.fi/feature/articles/109myths/ in the chapter about various myths.

The ingame BF109 flies like the dog it never was, the ingame sptifire flies like a Biplane completing turns sometimes below 10 seconds which is funny, I guess?



myfabi94, on 15 Feb 2015 - 12:00, said:
The Quotes I gave by Eric Brown were on the E-model. He noted that the Aircraft had no tendency to spin in a stall and from what I know the only model to be rather violent in that aspect was the A-D series.
I think many of the FM creators misunderstood some of the stability issues to be around the roll axis when in fact the were around the vertical axis.
Especially rudder effectiveness was low to counteract the torque.
"In this respect the Bf.109E scores by its excellent control near the stall and innocuous behaviour at the stall, giving the pilot confidence to get the last ounce out of his airplanes turning performance." from the same report.
There are lots of contradiciting reports concerning manouvarbility, but none mention violent spin and stall behaviour for the E-models. http://www.virtualpilots.fi/feature/articles/109myths/

The slats don't seem to have any effect.



myfabi94, on 18 Feb 2015 - 13:03, said:
"During what was later called the 'Battle of Britain', we flew the Messerschmitt Bf109E. The essental difference from the Spitfire Mark I flown at the time by the RAF was that the Spitfire was less maneuverable in the rolling plane. with its shorter wings (2 metres less wingspan) and its square-tipped wings, the Bf 109 was more maneuverable and slightly faster. (It is of interest that the English later on clipped the wings of the Spitfire.) The Bf 109s also had leading edge slots. when the 109 was flown, advertently or inadvertently, too slow, the slots shot forward out of the wing, sometimes with a loud bang which could be heard above the noise of the engine. Many times the slots coming out frightened young pilots when they flew the Bf 109 for the first time in aerial combat. One often flew near the stalling speed in combat, not only when flying straight and level but especially when turning and climbing. Sometimes the slots would suddenly fly out with a bang as if one had been hit, especially when one throttled back to bank steeply. Indeed many fresh young pilots thought they were pulling very tight turns even when the slots were still closed against the wing. For us, the more experienced pilots, real maneuvering only started when the slots were out. for this reason it is possible to find pilots from that period (1940) who will tell you that the Spitfire turned better than the Bf 109. That is not true. I myself had many dogfights with Spitfires and I could always out-turn them."

This is from "Messerschmitt Bf 109 At War" by Armand van Ishoven, page 58, "Fighting the Spitfire," by Erwin Leykauf, BOB 109 E pilot:



myfabi94, on 18 Feb 2015 - 13:59, said:
Well here is one example of the extreme difference in test results:

The German tests were done at combat cruise and conclude: Smallest turning radius without flaps was 170 meters, 125 meters with flaps.
Turn times for Bf109 in german tests were 18.92 seconds at a radius of 203 meters.
In a diving turn the German tests concluded 11.5 seconds for 50m/s dive and a radius of 190m.

British Comparative Tests between Spitfire and Hurricane concluded
Spitifre turn time was 19 seconds at 696ft radius/212 meters at 133mph IAS and
and now for the BIG SURPRISE: Bf109 results were: 270m turn radius and 25 seconds at 129 mph IAS and 2.1g

If you ask me there is something completely dorked in one of the tests, guess who I think fucked up? I'm quite confident that the tested Bf109E was a complete Dork and I don't know what the french did to it.
http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html#109E_turnradius
http://www.spitfireperformance.com/spitfire-I.html

[SorcererDave]

I think the above is a perfect example of why Team Fusion goes on hard data and the laws of physics in general before looking at anecdotal evidence. If we sat here gathering quotes from BoB pilots insisting their aircraft could out-turn the enemy's, we'd be here for months without reaching a conclusion. Far too many factors at play in situations like that which go far beyond the airframe itself. Hell even in CloD I've been out-turned by 109s in my Spit from time to time, usually when I'm going extremely slow, and well below my optimum cornering speed. And you see plenty of exclamations in the chat every now and again along the lines of "since when can the 109 out-turn Spits?!?!?!!!" If that's not an indication that Team Fusion seem to have got it mostly right, I dunno what is.