Bf109 Overreving when flying at high altitude

[Crump]

I suppose prop pitch reaches coarse limit (8:30 in pitch meter) by power-dive, thus automatic RPM can't keep 2500 rpm and become overrev.

 

I agree,  good observation!!  It was your input that had me watch Kieshar's video paying attention to the speed and altitude.  The airplane is way past Vne.

 

 

 

There are quite a few planes able to survive passing Vne!

 

That should definitely be corrected and a bug report submitted.

 

 

I find it a bit insulting how condescending you are, considering you never experienced the game physics yourself. My point is that the plane overrev now, while a few month ago it did not. And the bf109 can survive speed of up to 850 km/h with absolutely no problems in-game.

 

Kieshar, drop it please.

 

You questioned my experience with flight physics and I answered it.  End of story so let's move on. 

Edited November 26, 2014 by Crump

[kiershar]

I did not? Game physics != Flight physics. You read what you want, antagonize me with irrelevant questions and then talk about how you fly planes in real life. If anything, you are trolling this thread. And yes, end of story. I would have prefered not to hear your story at all.

[indiaciki]

i think I read in one of the 109 manuals - manual prop pitch before dive. not sure, though

Edited November 27, 2014 by indiaciki

[SKG51_robtek]

@Kiershar

 

i think you are, without any reason, way out of line in your last posts.

As this game is trying to simulate real flight physics, the game physics ca be compared to them.

There is a saying: if you dont like the answers you asked the wrong question.

Edited November 27, 2014 by I./ZG15_robtek

[Anw.StG2_Tyke]

It was not my issue Kieshar nor did I trumpt my education, you simply got butt hurt when I very nicely answered your question.

 

 

 

That probably should be fixed.  It is things like this that I am looking for before I drop 100 bucks on a game..... 

Nope it shouldn't because there are a lot of reports that the 109 dived faster than 800 km/h IAS and could only be recovered by using the horizontal stabilizer and so on. I guess you should as a aeronautic scientist that there is a difference between the Speed given in manuals and the destruction speed.

In the Manuals for the 109 F and G at is stated not to dive faster than 750 km/h. Yet a lot of pilots (Best documented finish Pilots) dived faster than that and survived, because the plane was capable of doing so.

Its the same with tha LaGG 3 in-game it can dive nearly 100 km/h faster than allowed in manuals, because of pilot reports.

[SKG51_robtek]

Nope it shouldn't because there are a lot of reports that the 109 dived faster than 800 km/h IAS and could only be recovered by using the horizontal stabilizer and so on. I guess you should as a aeronautic scientist that there is a difference between the Speed given in manuals and the destruction speed.

In the Manuals for the 109 F and G at is stated not to dive faster than 750 km/h. Yet a lot of pilots (Best documented finish Pilots) dived faster than that and survived, because the plane was capable of doing so.

Its the same with tha LaGG 3 in-game it can dive nearly 100 km/h faster than allowed in manuals, because of pilot reports.

This 800 km/h figure is useless without the correspondending altitude.

The speed in the manuals is to guarantee that the ship holds together in the normal flight envelope.

Above Vne anything can happen, from inverted controls to structural failure, especially if the plane was brought to its limits before.

The LaGG 3 should be able to do that, but with the risks mentioned above, there should be a structural failure now and then above Vne.

Edited November 27, 2014 by I./ZG15_robtek

[BlackDevil]

The 109 has been dived to sound speed without structural failure (vertical dive). But it was almost impossible to get it out of that dive.

[SKG51_robtek]

The 109 has been dived to sound speed without structural failure (vertical dive). But it was almost impossible to get it out of that dive.

800 km/h IAS at 5700 m will get you 0,8958 M or 1034 km/h TAS, i doubt the survability for a 109, especially when not brand new.

Maybe the aerodynamically cleaned un K4 could do that.

Edited November 27, 2014 by I./ZG15_robtek

[Anw.StG2_Tyke]

This 800 km/h figure is useless without the correspondending altitude.

The speed in the manuals is to guarantee that the ship holds together in the normal flight envelope.

Above Vne anything can happen, from inverted controls to structural failure, especially if the plane was brought to its limits before.

The LaGG 3 should be able to do that, but with the risks mentioned above, there should be a structural failure now and then above Vne.

Nope its not, because that would mean that Vne given in the manuals is useless, because it is given in IAS.

The speed in the manuals is to guarantee, that the pilot would survive and can control the plane without any problems. That's what those speeds indicates. Going over that speed means, that you as a Pilot could have problems. The Speed where the plane takes damage is somewhere between Vne and yeah, and we don't know it. Thats the problem, there are no data showing how fast the planes could dive with taking serious damage.

But what we know is, that there are some reports of pilots with 109 G's dived faster than 800 km/h IAS without any damage on the 109's. So we can assume, that the 109 was perfectly capable of diving over 750 km/h without any damage.

[SKG51_robtek]

Nope its not, because that would mean that Vne given in the manuals is useless, because it is given in IAS.

The speed in the manuals is to guarantee, that the pilot would survive and can control the plane without any problems. That's what those speeds indicates. Going over that speed means, that you as a Pilot could have problems. The Speed where the plane takes damage is somewhere between Vne and yeah, and we don't know it. Thats the problem, there are no data showing how fast the planes could dive with taking serious damage.

But what we know is, that there are some reports of pilots with 109 G's dived faster than 800 km/h IAS without any damage on the 109's. So we can assume, that the 109 was perfectly capable of diving over 750 km/h without any damage.

That doesn't compare to the diagram posted a few posts before about the maximum reachable speed of the 109, which was 737 km/h.

[Anw.StG2_Tyke]

That doesn't compare to the diagram posted a few posts before about the maximum reachable speed of the 109, which was 737 km/h.

But in that document it is never stated, that they wanted to find out how fast the 109 can dive?

I don't know if you read or speak german, but this document is about a test with modified 109's because there were reports from the Troop that diving with 750 km/h IAS the plane behaved strangely. Thats why this test was initiatet, they made some modifications and tested them. The results were, that this behaviour could be eliminated with some modifications. They made later in that report that they did "Endsturzversuche" they achieved speeds above 750 km/h without any problems:

http://www.wwiiaircraftperformance.org/me109/me109-dive.pdf

Page 6 in the PDF.

[SKG51_robtek]

But in that document it is never stated, that they wanted to find out how fast the 109 can dive?

I don't know if you read or speak german, but this document is about a test with modified 109's because there were reports from the Troop that diving with 750 km/h IAS the plane behaved strangely. Thats why this test was initiatet, they made some modifications and tested them. The results were, that this behaviour could be eliminated with some modifications. They made later in that report that they did "Endsturzversuche" they achieved speeds above 750 km/h without any problems:

http://www.wwiiaircraftperformance.org/me109/me109-dive.pdf

Page 6 in the PDF.

In this document the max. Mach number is 0.808 at 290 mmHG (page 8).

That computes to 640 km/h IAS at 7242 m and 903 km/h TAS.

At page 7 the max. TAS is a little bit over 900 km/h.

At Page 6 the max IAS is about 768 km/h at 3550m, giving 896 km/h TAS but as indicated not measured by a calibrated Instrument.

The max. speed measured by a calibrated Instrument was 725 IAS at 4206 m giving 873 TAS.

So there is one measurement in five for a IAS above 750 km/h, not really a base for arguments, imo

[Anw.StG2_Tyke]

In this document the max. Mach number is 0.808 at 290 mmHG (page 8).

That computes to 640 km/h IAS at 7242 m and 903 km/h TAS.

At page 7 the max. TAS is a little bit over 900 km/h.

At Page 6 the max IAS is about 768 km/h at 3550m, giving 896 km/h TAS but as indicated not measured by a calibrated Instrument.

The max. speed measured by a calibrated Instrument was 725 IAS at 4206 m giving 873 TAS.

So there is one measurement in five for a IAS above 750 km/h, not really a base for arguments, imo

Where do you get the information that those instrument weren't calibrated?

It is well written in the document that they even used the Askania Telemetry Device for those tests.

Furthermore, this test was about testing the unstability problem which came back from the troops. And they SOLVED that problem, so they could dive without any problems 750 km/h. Thats all written there.

[MiloMorai]

750kph ONLY below 3000m.

 

[Anw.StG2_Tyke]

750kph ONLY below 3000m.

 

According to that document the plane in the trial mentioned earlier had to take a lot of damage... because it was over the allowed speeds...

[LLv34_Flanker]

S!

 

 Signed by WCMDR named Proctor. Reminds me of Police Academy

[SKG51_robtek]

@ Auva

 

just because there isn't any damage mentioned doesn't mean there wasn't any.

It is possible that damage was expected and handled as a normal result from overspeed conditions.

Be assured that after each dive the structure was inspected and repaired, if necessary.

In page 6, upper left side, is mentioned that in 2 dives the Askania device was used an in 1 dive photos were taken.

Also you can be sure that in combat such a high speed dive was a last ditch defensive maneuvre,

as the pilots didn't risk their lives with unnecessary risks.

The physics in game should enforce this playing by the rules to create a more real environment.

Edited November 27, 2014 by I./ZG15_robtek

[Anw.StG2_Tyke]

@ Auva

 

just because there isn't any damage mentioned doesn't mean there wasn't any.

It is possible that damage was expected and handled as a normal result from overspeed conditions.

Be assured that after each dive the structure was inspected and repaired, if necessary.

In page 6, upper left side, is mentioned that in 2 dives the Askania device was used an in 1 dive photos were taken.

Also you can be sure that in combat such a high speed dive was a last ditch defensive maneuvre,

as the pilots didn't risk their lives with unnecessary risks.

The physics in game should enforce this playing by the rules to create a more real environment.

Excuse me that I as a sciencist have to tell you something about that:

You don't start a experiment without calibrating your instruments. People who do those experiments have to deliver data which has a credibility. You don't have to mention that your instruments are calibrated because everybody in the science community EXPECT that from you. And so it is with those tests there.

Secondly, the Askania device was used in 4 of 5 on page 6. The First test there is Askania written, on the second and third test there are only ". In Germany we use those " in the next line to show that we used the same word as in the line before because of lazyness. In the Fourth test, they documented the speed with a photograph. And in the last Test they again used the Askania device.

Im fully on your side when it comes to the dangerous high speed dive as a last ditch defensive maneuvre. And thats the problem, nobody ever tested this dive for gathering data because it was so dangerously.

[Crump]

 

 

The 109 has been dived to sound speed without structural failure (vertical dive). But it was almost impossible to get it out of that dive.

 

Never happened.  Not going to argue the point either, it is like arguing if the world is round or flat.  Because folks thought it was flat does not make it true.

 

There are real barriers to the Bf-109 breaking the speed the sound it just could not surmount under any circumstances and that is scientific fact.

 

 

 

According to that document the plane in the trial mentioned earlier had to take a lot of damage... because it was over the allowed speeds...

 

No, it was not allowed to overspeed.   Pilots exceeded the limitations, destroyed the aircraft, and killed themselves.  Vne is set by very real barriers.

 

This topic has been covered in depth.

 

Pay particular attention to post number 47.

 

http://forum.il2sturmovik.com/topic/4948-fw-190-and-bf-109-longitudinal-stability-and-control/?p=104210

 

http://forum.il2sturmovik.com/topic/4948-fw-190-and-bf-109-longitudinal-stability-and-control/ 

[Crump]

just because there isn't any damage mentioned doesn't mean there wasn't any. It is possible that damage was expected and handled as a normal result from overspeed conditions. Be assured that after each dive the structure was inspected and repaired, if necessary. In page 6, upper left side, is mentioned that in 2 dives the Askania device was used an in 1 dive photos were taken. Also you can be sure that in combat such a high speed dive was a last ditch defensive maneuvre, as the pilots didn't risk their lives with unnecessary risks. The physics in game should enforce this playing by the rules to create a more real environment.

 

 

Absolutely correct.

 

There was not only damage, there was loss of life and that fact prompted the high speed flight investigations by Mtt at the RLM's insistance.  As with most aircraft of the day, the Vne of the Bf-109 was not flight tested, it was a calculated figure.  Flight investigations were just too risky.

 

Nobody spends money and time investigating non issues. 

 

Since stability and control was still a burgeoning science during World War II many designs like the Bf-109 encountered issues not foreseen in the aerodynamic calculations for Vne.  Flutter, snaking, dutch roll, compressibility and a whole host of other stability issues cropped up.  Concepts like the Aerodynamic Center shift at high speed where just unknown at the time these airplanes were designed.  Subsonic incompressible flow theory was highly developed but the realm of compressible aerodynamics in the transonic realm was not.  Supersonic aerodynamics was a virtual unknown and was hotly debated as to the actual effects on an aircraft.

 

There were a number of compressibility correction theory in use at time. There was no "universal correction" as is in use today.

 

 

 

 

I have included some material from AIAA library that will help folks to understand the state of the science at the time.  

Included is the history of flutter research.    Flutter is the most common dynamic pressure effect and it is the onset of flutter that most commonly is used to determine Vne.

Flight Testing WWII Aircraft.pdf

Development of High Speed flight.pdf

Historical development of aircraft flutter.pdf

Edited November 27, 2014 by Crump

[JtD]

The Speed where the plane takes damage is somewhere between Vne and yeah, and we don't know it.

The maximum permissible speed is a result of a calculation done during the design process and of course comes with a safety factor. You're absolutely right about that. In case of the 109 I don't recall it for certain, but I think it added up to about 1.3, either dynamic pressure or speed. However, this factor was for a single load scenario, i.e. just high speed. If you combined high speed for instance with maximum g and/or maximum aileron deflection, the safety factor became marginal at best.

 

It should also be kept in mind that this factor was for structural strength only, and loss of control or something wasn't covered.

[Crump]

JtD,

 

You are right regarding structural load bearing calculations.  That does not have anything to do with control surface resonance that determine flutter limits.

[Crump]

750kph ONLY below 3000m.

 

That is IAS which you confuse with TAS.  Exceeding 800 kph IAS in the game is exceeding Vne of the design.

 

The fact the modified test aircraft reached 900 kph TAS on several occasions has little to do with what the service aircraft Vne limits.  The operational aircraft were rigged for service, not to safely investigate the high speed flight limits to determine the onset speed of adverse behaviors.

 

That onset speed for adverse behavior is what determines the Vne for the service aircraft.  Exceed Vne and you will see adverse behaviors that are very real and deadly.

Edited November 27, 2014 by Crump

[DD_bongodriver]

Doesn't seem like Milo has confused anything, it clearly states 750 kmh IAS below 3000M.

Edited November 27, 2014 by DD_bongodriver

[Anw.StG2_Tyke]

That is IAS which you confuse with TAS.  Exceeding 800 kph IAS in the game is exceeding Vne of the design.

 

The fact the modified test aircraft reached 900 kph TAS on several occasions has little to do with what the service aircraft Vne limits.  The operational aircraft were rigged for service, not to safely investigate the high speed flight limits to determine the onset speed of adverse behaviors.

 

That onset speed for adverse behavior is what determines the Vne for the service aircraft.  Exceed Vne and you will see adverse behaviors that are very real and deadly.

Look at the test, the Aircraft exceeded that IAS well beyond 750 km/h at a higher altitude.

I don't confuse anything because I only speak in IAS. TAS is not relevant when we talk about the Divingspeed and the Vne of the plane because in the german manuals and tests nearly everything is stated in IAS.

 

My point is, and is backed of the data: The Bf 109 could easily exceed the given Vne=750 km/h IAS without taking any damage. There are enough reports from pilots who dived 800 to 880 km/h IAS. The TAS is not from interest because, everything stated for that topic is given in IAS from Messerschmitt untill to the Pilot-Stories which stated the Speed given by the "Staurohr" (Pitottube). Can the Bf 109 dive to the Sound barrier? Hell NO NO not in 1000 years and in NO wet dreams of Luftwaffe-Fanboys. But saying, the 109 dives too good in the game, because Vne was stated with 750 km/h and it shouldn't dive faster without damage is plain wrong because we now it did. (Sure somewhere has to be the point and I think a 10 to 20% margin would be a good approach).

 

And for you, IF there would be ANY Damage at the Test-Plane from the RLM-Test it would have been noted, because it was important for Rechlin and Messerschmitt. Those tests were no propaganda at all, they were scientific tests to improve the Weapon for the World War II. What the hell do you think? The Germans tested the reported problems, and nowhere stated damage after those dives? Come on, that would be dumb from every scientist and Mr. Messerschmitt would kicked his butt over to Stalingrad himself. (I strongly belief that this would happen in every other test-side because the basics of scientific work is no rocket science).

Edited November 27, 2014 by Stab/JG26_Auva

[Bearcat]

Get a grip folks. Stay focused or this thread will be locked.

[SKG51_robtek]

@Stab/JG26_Auva

 

I'd really like to see those anecdotal reports of reaching 880 km/h or even 800 km/h IAS.

But the maximum proven speed the BF109 could reach is 768 km/h IAS at 3550m, fact.

The rest are just stories and memories of a high speed dive with lots of adrenalin in a vibrating airframe and looking at a vibrating needle in a also vibrating Fahrtmesser.

[Crump]

TAS is not relevant when we talk about the Divingspeed

 

 

 

MMMM...TAS is the determining factor in mach limits.

 

 

 

Look at the test, the Aircraft exceeded that IAS well beyond 750 km/h at a higher altitude.

 

 

 

Not in Indicated AirSpeed....

 

 

There is one single data point outside of 750 kph and that hardly represents complete data much less routinely exceeding the 750kph IAS Vne limit.  

 

We can say it is an outlier simply by the fact Mtt did not raise the limits to the single point at 770kph at 2800m but chose to ignore it and go with all the other data points that show 750 kph below 3000 meters.  

 

 

Outlier

In statistics, an outlier is an observation point that is distant from other observations. An outlier may be due to variability in the measurement or it may indicate experimental error; the latter are sometimes excluded from the data set.

 

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

Diving_Test_109F_W.Nr.9228_ger_eng.pdf

[Anw.StG2_Tyke]

@Stab/JG26_Auva

 

I'd really like to see those anecdotal reports of reaching 880 km/h or even 800 km/h IAS.

But the maximum proven speed the BF109 could reach is 768 km/h IAS at 3550m, fact.

The rest are just stories and memories of a high speed dive with lots of adrenalin in a vibrating airframe and looking at a vibrating needle in a also vibrating Fahrtmesser.

Sure, why not:

Me 109 G:

"Me 109 had good and accurate weapons, but those were the only good points of it. To me, it's unacceptable that somebody had built a fighter plane that couldn't be dived without limits. Me109 had a dive limit of 880km/h - you weren't to exceed it or the plane would break up. Just this happened to Sgt Mäittälä. I (and Pokela) was forced to exceed this limit twice, I can't describe how it felt just to sit in the cockpit waiting, if the plane would break up. I have never gotten rid of that feeling, of being trapped."

-Heimo Lampi, Finnish fighter ace. 13 1/2 victories. Source: Hannu Valtonen, "Me 109 ja Saksan sotatalous" (Messerschmitt Bf 109 and the German war economy), ISBN 951-95688-7-5.

 

Me 109 G:

"-Someone asked of the top speed of the Me. Mr Väinö Pokela told earlier it's 720 km/h, when I interviewed him.

Normally we flew the Me at 500 km/h, but at a tough spot we could go some 600 km/h. But the absolute speed limit is found in dive. I had to do some over 900 km/h dives. The speedometer scale ends at 900, and at that you feel the flutter effect in the wings. Guess it was very near the top speed, when the plane felt like falling apart."

- Edvald Estama, Finnish fighter pilot. Source: Recollections by Eino and Edvald Estama by Finnish Virtual Pilots Association.

 

I came in and got to the leader of the wolf pack and got his left wing.  Flames you know.  With this tremendous amount of fuel you get a flame.  Then I cut to the right and I was hunted. Then they chased me.  I should tell you the numbers.  It was 800 4-engine bombers, B-17, B-24.  This is a parade of 2 hours.  They had cover of 1200 fighters from the Hartz mountains down to Stutgard.  Always in 4, 4 or other formations.  So it without chance.  Anyway, I was chased by  P-47.  I knew exactly that in a dive P-47 is much faster than 109.  And the P-47 has a much higher structural strength. They can go up to 1400 kilometers per hour. The 109, if you go to 1000, pull it up, you risk that the wings come off.  So I went down from that, bang, bang, bang.  I was chased by what we call line abreast, 4 p-47s.  And all that shooting here and all of a sudden bang. The left hand was on the throttle and came off and the thumb was off.  Finally, I managed.  This was a very traumatic thing, certainly.  I pull up, when I was down, to the stalling point.  The couldn't follow me because these P-47 wanted to fly back to England.  And I want to get rid of my airplane. I don't care for the airplane, I want to get out of this.  I managed that.  This was very difficult because I was hanging outside. I couldn't operate with this hand, nothing.  Finally it worked and I pulled the parachute way down and I came down safely and was hanging on a tree.

Günther Rall's Lecture at the Aviation Museum Society, Finland.

[Crump]

One can simply open the Bf-109 series Flugzeug Handbuch and see the results of the high speed flight investigation.  It is represented in the more detailed and restrictive Vne limits placed on later Bf-109's.  The Bf-109E and F series had a blanket Vne of 750kph IAS at all altitudes.

 

After the high speed investigation, that Vne was restricted by altitude as more detailed data on the aircraft's behavior became available.  Pretty common occurrence in WWII designs actually.

[Crump]

Sure, why not:

Me 109 G:

"Me 109 had good and accurate weapons, but those were the only good points of it. To me, it's unacceptable that somebody had built a fighter plane that couldn't be dived without limits. Me109 had a dive limit of 880km/h - you weren't to exceed it or the plane would break up. Just this happened to Sgt Mäittälä. I (and Pokela) was forced to exceed this limit twice, I can't describe how it felt just to sit in the cockpit waiting, if the plane would break up. I have never gotten rid of that feeling, of being trapped."

-Heimo Lampi, Finnish fighter ace. 13 1/2 victories. Source: Hannu Valtonen, "Me 109 ja Saksan sotatalous" (Messerschmitt Bf 109 and the German war economy), ISBN 951-95688-7-5.

 

Me 109 G:

"-Someone asked of the top speed of the Me. Mr Väinö Pokela told earlier it's 720 km/h, when I interviewed him.

Normally we flew the Me at 500 km/h, but at a tough spot we could go some 600 km/h. But the absolute speed limit is found in dive. I had to do some over 900 km/h dives. The speedometer scale ends at 900, and at that you feel the flutter effect in the wings. Guess it was very near the top speed, when the plane felt like falling apart."

- Edvald Estama, Finnish fighter pilot. Source: Recollections by Eino and Edvald Estama by Finnish Virtual Pilots Association.

 

I came in and got to the leader of the wolf pack and got his left wing.  Flames you know.  With this tremendous amount of fuel you get a flame.  Then I cut to the right and I was hunted. Then they chased me.  I should tell you the numbers.  It was 800 4-engine bombers, B-17, B-24.  This is a parade of 2 hours.  They had cover of 1200 fighters from the Hartz mountains down to Stutgard.  Always in 4, 4 or other formations.  So it without chance.  Anyway, I was chased by  P-47.  I knew exactly that in a dive P-47 is much faster than 109.  And the P-47 has a much higher structural strength. They can go up to 1400 kilometers per hour. The 109, if you go to 1000, pull it up, you risk that the wings come off.  So I went down from that, bang, bang, bang.  I was chased by what we call line abreast, 4 p-47s.  And all that shooting here and all of a sudden bang. The left hand was on the throttle and came off and the thumb was off.  Finally, I managed.  This was a very traumatic thing, certainly.  I pull up, when I was down, to the stalling point.  The couldn't follow me because these P-47 wanted to fly back to England.  And I want to get rid of my airplane. I don't care for the airplane, I want to get out of this.  I managed that.  This was very difficult because I was hanging outside. I couldn't operate with this hand, nothing.  Finally it worked and I pulled the parachute way down and I came down safely and was hanging on a tree.

Günther Rall's Lecture at the Aviation Museum Society, Finland.

 

 

Do you understand that a stock airspeed indicator will read exactly what these gentlemen tell us.  What that airspeed indicator read has ABSOLUTELY nothing to do with how fast the airplane is traveling in the transonic realm.

 

Simply put, you had to have special airspeed measuring equipment that was outside the influence of normal shock formation to have any kind of hope in having some semblance of accuracy.  Anyone with the knowledge can look at the speed measuring equipment and placement of the static port's to determine if the measurement method was valid.

 

On an operational Bf-109 series, it was not in a position to even remotely measure accurate data at high transonic speeds.

[Anw.StG2_Tyke]

MMMM...TAS is the determining factor in mach limits.

 

 

 

 

 

 

Not in Indicated AirSpeed....

 

05e43_p5 One data point.jpg

 

There is one single data point outside of 750 kph and that hardly represents complete data much less routinely exceeding the 750kph IAS Vne limit.  

 

We can say it is an outlier simply by the fact Mtt did not raise the limits to the single point at 770kph at 2800m but chose to ignore it and go with all the other data points that show 750 kph below 3000 meters.  

 

 

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

I guess you don't understand what Mtt tested at that trail and why they didn't dived faster than 750 km/h.

Messerschmitt had with that trial NEVER the intention to test the maximum dive speed of the Bf-109. They wanted to test the strange behaviour reported from the troops. So for gods sake, they stayed in the given safety parameter to not exceed 750 km/h.

And the 109 exceeded 750 km/h in Indicated Air Speed, its in the diagram provided. You even redlined it. And no that test curve is not an outlier, because the error would be way to high to accept the gathered data.

You can't accept it, that Mtt only wanted to test in that trail how the 109 behaves at a certain dive speed and how to cope with a problem. And based on that you exagerate, hey the 109 couldn't dive faster, but you don't realized that this trial wasn't meant to show how fast the 109 can dive.

 

Come on as I read you have a degree in a scientific subject, you should know better. You can't answer a question which you don't want to investigate. Its like testing the degradation of tyres up to 180 km/h and based of that data saying, those tyres can not be used faster than 180 km/h but you never tested it how fast they could be used. And that is the case here.

 

Oh and guess what, that data is not an outlier, because hell this data can't even be used for statistical evaluation. You can use statistical evaluation if you wan't to compare two or more data sets and wan't to see if there is a difference or not. This is not possible with the provided data because the provided data is not made for that question. You could analyse the mean but, well this gives you nothing because, the pilot wasn't told to dive as fast as he can. The pilot was told to make a dive with the 109 because of a specific problem reported by the troops. (Suspicious aileron and rudder behaviour above 650 km/h). It is even stated later in the document, that after the modifications were done, the plane was flown to the data provided later. Now lets become scientific for a moment, we gathered what data in terms of speeds. We gathered a bunch of data where the plane achieved speeds in a range which was set by the engineers. You can't say anything about the achievable topspeed of a plane, when you don't test where it takes damage.

 

 

Do you understand that a stock airspeed indicator will read exactly what these gentlemen tell us.  What that airspeed indicator read has ABSOLUTELY nothing to do with how fast the airplane is traveling in the transonic realm.

 

Simply put, you had to have special airspeed measuring equipment that was outside the influence of normal shock formation to have any kind of hope in having some semblance of accuracy.  Anyone with the knowledge can look at the speed measuring equipment and placement of the static port's to determine if the measurement method was valid.

 

On an operational Bf-109 series, it was not in a position to even remotely measure accurate data at high transonic speeds.

I understand that a stock airspeed indicator will show that to me, what those pilots said, and I never said anything different. Because It doesn't matter, it doesn't matter how fast the airplane is traveling in the transonic realm because we don't have the possibility to measure it in BoS nor have we any possibility to get those data. All what we ingame have is a Airspeed-Indicator which shows us how fast we are in IAS. And this thing should be nearly as good as the real ones. So when I dive with my 109 ingame and I achieve 880 km/h's with the ingame pitottube airspeed indicator, well I guess this would be pretty realistic and not wrong at all.

Edited November 27, 2014 by Stab/JG26_Auva

[MiloMorai]

That is IAS which you confuse with TAS.  Exceeding 800 kph IAS in the game is exceeding Vne of the design.

 

When did the 109 get an air speed instrument that showed TAS?

 

 

Simply put, you had to have special airspeed measuring equipment that was outside the influence of normal shock formation to have any kind of hope in having some semblance of accuracy.  Anyone with the knowledge can look at the speed measuring equipment and placement of the static port's to determine if the measurement method was valid.

 

On an operational Bf-109 series, it was not in a position to even remotely measure accurate data at high transonic speeds.

 

 

Is this location outside the normal shock formation?

 

[LLv34_Flanker]

S!

 

 Finnish pilots exceeded the 750km/h in numerous occasions when disengaging from VVS pilots. This because they knew not a single VVS fighter could follow them in those dives. A few had tried and lost their wings thus lawndarting. When Ilmari Juutilainen, credited with 93 confirmed victories, had performed one of these high speed dives the speedometer had gone "all the way round" and he barely managed to recover from the dive with 200m to spare. The plane held, but was later lost in a high speed dive when tail unit came off and another pilot flying the plane was lost. Recovery was propably done with too high force and plane broke. But no damage to the plane was reported after Ilmari's high speed dive. Planes could be flown over the limits, but it was lottery if the plane held or not especially later in the war when quality of planes varied or they were overhauled from already flown fuselages.

 

 You can debate all day long, but the fact stands that these limits were exceeded in an emergency and pilots lived to tell about it. Knowing your limits vs opponent's limits could save your life. And that was exactly what FiAF pilots did, utilized the very much higher speed tolerance of their Bf109G's to shake off VVS fighters that could not withstand high speed dives, not even the La-5FN or Yak-9, that were encountered in numbers during 1944.

[SKG51_robtek]

.......

I understand that a stock airspeed indicator will show that to me, what those pilots said, and I never said anything different. Because It doesn't matter, it doesn't matter how fast the airplane is traveling in the transonic realm because we don't have the possibility to measure it in BoS nor have we any possibility to get those data. All what we ingame have is a Airspeed-Indicator which shows us how fast we are in IAS. And this thing should be nearly as good as the real ones. So when I dive with my 109 ingame and I achieve 880 km/h's with the ingame pitottube airspeed indicator, well I guess this would be pretty realistic and not wrong at all.

The error in this logic is, imo, that the airspeed indicator deviation at higher Mach numbers had, and will have, a very low priority in the programming process.

So we have a airspeed indicator in game showing what the askania device would show, real IAS.

So reaching 880 km/h in game would be very wrong.

As a matter of fact, going faster than the Vne's posted in post #54 should result in structural damage when additional forces are there, i.e unsensible maneuvring.

If Vne is exceeded by, say 10% to15% structural damage should occur resulting without additional forces.

The pilots then had to be aware of the ability of their rides to destruct themselves when mishandled, it should be the same in game.

That the LaGG can safely dive 100 km/h faster than Vne in game, proven by pilots account only, afaik, is very wrong, as no one can tell how big the deviation of the speed indicator was.

Edited November 28, 2014 by I./ZG15_robtek

[6./ZG26_5tuka]

That's basicly what I'm talking about. Maths are great and documents are of course the beacon in terms of FM development, but both should always be reflected by the creator and measured practicly to review their legitimacy in game.

Apart from that DMs are not detailed enought to represent this feauture apparently. It only modeles controll surface loss due to speed stress, no structual failure apparently.

 

Hopefully this is going to be added in feauture as it's an important part in aerial combat and certainly causes disbalance currently.

I've no documents about tachometer deviation, so my bet is - if it's really not implemented ingame - it may not nessecary to take it into account at all given they had to make up artificial guess values for it anyway.

[Anw.StG2_Tyke]

The error in this logic is, imo, that the airspeed indicator deviation at higher Mach numbers had, and will have, a very low priority in the programming process.

So we have a airspeed indicator in game showing what the askania device would show, real IAS.

So reaching 880 km/h in game would be very wrong.

As a matter of fact, going faster than the Vne's posted in post #54 should result in structural damage when additional forces are there, i.e unsensible maneuvring.

If Vne is exceeded by, say 10% to15% structural damage should occur resulting without additional forces.

The pilots then had to be aware of the ability of their rides to destruct themselves when mishandled, it should be the same in game.

That the LaGG can safely dive 100 km/h faster than Vne in game, proven by pilots account only, afaik, is very wrong, as no one can tell how big the deviation of the speed indicator was.

But we don't know what happened beyond Vne because nobody tested it. We only know that Pilots mentioned to be faster than that, and that they survived it. Others died, it is known in the provided documents the biggest problem at Vne or exceeding it was the unstable behaviour and a wrong counter-steering which induced a yawing which leads to wing breakages.

We have no evidence at all, what happens beyond Vne except in one test, where they tested something comepletly different the plane exceeds Vne and there is no damage reported at all. THIS are the provided FACTS.

Now we have two different approaches, approach one:

We say the Vne given in Manuals is a hard line and the if you go over it you take damage line without any margin

Approach two:

The given Vne is a safety number provided by the engineers, where they can guarantee that a significant number of pilots would survive a dive into it, going further that speed is possible but risky when you don't react the right way.

 

 

My opinion is going approach two, because as a scientist I know how we give safety margins, they are often on a level to ensure that nobody gets affectet from that.

[SKG51_robtek]

@Stab/JG26_Auva

 

Yep, your version 2 is, as i see it, similar to my approach.

So if a pilot goes faster than i.e. 450 km/h IAS at 11000m (Vne 400 km/h) there should be damage to his plane.

When that pilot is doing hard evasive action at 400+ km/h in 11000 m there should also be damage.

At lower altitudes the IAS will be of course higher until below 3000 m 750 km/h is Vne

Edited November 28, 2014 by I./ZG15_robtek

[LLv34_Flanker]

S!

 

 What would cause this damage? In game all planes are factory new, no strain on them etc. so DM can't be like "IF speed > 400km/h THEN damage". There is a certain margin of safety on top of the Vne. What it is, hard to say. I would guess 10-20%. That would give some reserve to go past Vne without thrashing the plane, but pushing it over the safety margin would be increasingly dangerous. And modelling this would open the can of worms, once again, about bias and whatnot. Frankly not giving a flying fart, saving my nerves and playing something totally different. Ahh, the bliss!

[SKG51_robtek]

S!

 

 What would cause this damage? In game all planes are factory new, no strain on them etc. so DM can't be like "IF speed > 400km/h THEN damage". There is a certain margin of safety on top of the Vne. What it is, hard to say. I would guess 10-20%. That would give some reserve to go past Vne without thrashing the plane, but pushing it over the safety margin would be increasingly dangerous. And modelling this would open the can of worms, once again, about bias and whatnot. Frankly not giving a flying fart, saving my nerves and playing something totally different. Ahh, the bliss!

But i wrote the damage should happen when exceeding the Vne by 15% without manoevering and anytime above Vne with hard manoevres.

If the limits above Vne are the same for all fighters, a little higher for dive-bombers and lower for bombers, then there is no bias.