New D-9 FM since 2.0?

Hummingbird · December 16, 2015

I am back to work so it will be at least 4 days.

Alright, sometime saturday perhaps?

otto · December 17, 2015

:doh:

Also let me add that the person that started this thread is the same guy that said the 109 was borked because he couldn't do a loop or cuban 8 with it...

Percy Spencer, an engineer with the Raytheon Corporation discovered the effects of micro waves on food because a candy bar melted in his pocket while he was working on an active radar set .Sometimes brilliant discoveries are made by chance.

Who started this thread has nothing to do with what Crump and Hummingbird have presented.

NineLine · December 17, 2015

Percy Spencer, an engineer with the Raytheon Corporation discovered the effects of micro waves on food because a candy bar melted in his pocket while he was working on an active radar set .Sometimes brilliant discoveries are made by chance.

Who started this thread has nothing to do with what Crump and Hummingbird have presented.

And the point you are missing is that nothing has been shown yet that has convinced ED there is an issue.

otto · December 17, 2015

And the point you are missing is that nothing has been shown yet that has convinced ED there is an issue.

I didn't say there is an issue .

NineLine · December 17, 2015

I didn't say there is an issue .

Ok, so OT, lets get back on topic then. If you have something to add to the topic in the way of evidence for trying to show there is a bug, please submit it, otherwise its not helping, and that is not directed at anyone in particular.

Edited December 17, 2015 by NineLine

Hummingbird · December 17, 2015

And the point you are missing is that nothing has been shown yet that has convinced ED there is an issue.

I really don't understand this though considering that the tests clearly show that the ingame aircraft aren't exhibiting the behavior of even the developers own charts: let alone the charts by Crumpp which are based on real life figures.

It seems like its very hard to get the acknowledgement of the devs for some reason. Perhaps I have been too open with my criticism before and Yo Yo has simply taken a dislike to me? I hope not.

NineLine · December 17, 2015

I really don't understand this though considering that the tests clearly show that the ingame aircraft aren't exhibiting the behavior of even the developers own charts: let alone the charts by Crumpp which are based on real life figures.

It seems like its very hard to get the acknowledgement of the devs for some reason. Perhaps I have been too open with my criticism before and Yo Yo has simply taken a dislike to me? I hope not.

Yo-Yo has commented on most everything you guys have put forward though.

Hummingbird · December 17, 2015

Yo-Yo has commented on most everything you guys have put forward though.

Very vaguely SiTh, he hasn't shown what numbers he's using or even explained what he thinks is wrong with Crumpp's data - let alone explained why the aircraft aren't even performing as his own charts indicate. He mentions prop efficiency but then he brings no figures forth. Next he mentions wing to weight ratio, and then aspect ratio, again though without making any real point. Meanwhile Crumpp has been going into great depth explaining his figures, providing original source material as he went.

You must understand that this looks a little odd?

I just don't want to be the reason this isn't looked into, thus if I'm the reason Yo Yo is disregarding this and other testers are prefered then I can accept that and will gladly step away. I know the results will be the same though, but if me stepping away will help get it corrected then I will gladly do so.

NineLine · December 17, 2015

Very vaguely SiTh, he hasn't shown what numbers he's using or even explained what he thinks is wrong with Crumpp's data - let alone explained why the aircraft aren't even performing as his own charts indicate. He mentions prop efficiency but then he brings no figures forth. Next he mentions wing to weight ratio, and then aspect ratio, again though without making any real point. Meanwhile Crumpp has been going into great depth explaining his figures, providing original source material as he went.

You must understand that this looks a little odd?

I just don't want to be the reason this isn't looked into, thus if I'm the reason Yo Yo is disregarding this and other testers are prefered then I can accept that and will gladly step away. I know the results will be the same though, but if me stepping away will help get it corrected then I will gladly do so.

I believe Yo-Yo has looked into it, and why he is dismissive of this thread at this point. At no point is ED or Yo-Yo required to prove anything though, and Yo-Yo shouldn't have to defend his FM anytime someone loses a dogfight they think they should have never lost. Its certainly nothing personal in regards to anyone. The videos I have seen can be seen a number of ways, as I have stated. I personally am still playing with it in my limited free time, but of course I am going to side with Yo-Yo if he says his FMs are fine.

My understanding is purely this, at the speeds we are talking, the aircraft are close enough that the smallest slip could result in one aircraft gaining the advantage over the other. I mean I am not math geniuses like you guys (and that is not smartass, I am serious, you guys know the math stuff good), but what what is the margin of error on all historical data, and sim data? Has any of that been taken into account, or do we assume we are all perfect pilots? Again, that is not meant to be smartass, but I have to look at it like that.

Edited December 17, 2015 by NineLine

Hummingbird · December 17, 2015

We have tried it with auto rudder and zero slip though, and the result is the same. At the speeds which the Dora should be outturning the P-51 it simply doesn't, not even close. Infact it has to slow down to below its supposed best turning speed to even delay the P-51 getting on its six faster. Anyone can try this for themselves as well. The level of superiority the P-51 enjoys ingame atm is significant.

The reasons for this can be many. Perhaps Yo Yo is using too high a prop efficiency for the P-51? Perhaps it's the CL? Perhaps its internal weight figures we can't see? Or perhaps as Crumpp has suggested, and I think this is very possible, something changed unintentionally with recent patches. Either way we have no way of telling any of this unless Yo Yo presents the basic figures he is using - which shouldn't be a secret btw as they're only a small part of building a simulation game flight model, thus he wont be revealing anything to the competition. But no he doesn't have to show them, it would just help a lot if he did.

The reason he isn't overly concerned with this subject atm might be that he has his hands full with other things right now of course, but I really don't see how the evidence can be disputed at this point - esp. when Yo Yo himself says the Dora will outturn the P-51.

jester_ · December 18, 2015

We have no way of telling any of this unless Yo Yo presents the basic figures he is using - which shouldn't be a secret btw as they're only a small part of building a simulation game flight model, thus he wont be revealing anything to the competition. But no he doesn't have to show them, it would just help a lot if he did.

This is really the kicker. I don't understand the secrecy of not sharing data regarding flight models and performance in sim games, at the very least for aircraft that are well beyond age. I could understand keeping that info under wraps for aircraft like the A-10, or the upcoming Hornet, but for prop planes flown in World War II, it's almost ridiculous.

I think a lot of instances where people challenge Yo Yo's FM data because they lost in a fight would be nipped in the bud if access to that data was open.

It is incredibly frustrating to try to bring what we think is a problem to the developer, demonstrate the alleged problem over and over, compare it to data that we find only to be told, "That's inconsistent with our data. Good luck."

NineLine · December 18, 2015

Again, he responded to everything, its not on him to convince you he is right, he has to convince the head of ED that he is the best man for the job, that's why he has a job doing this for a living. I dont know what else I can say.

jester_ · December 18, 2015

Again, he responded to everything, its not on him to convince you he is right, he has to convince the head of ED that he is the best man for the job, that's why he has a job doing this for a living. I dont know what else I can say.

I speak for me, but I don't consider "No, our model is correct, trust me." as a response to a genuine inquiry into whether or not something is not working properly after a massive update. I kind of feel like a lot of people are frustrated because they (we) feel like we aren't being taken seriously.

But I only consistently fly the 109 so I don't have any other input other than my own experiences in 2.0 with the Dora which is irrelevant because I never fight the turn fight.

Edited December 18, 2015 by jester_

NineLine · December 18, 2015

I speak for me, but I don't consider "No, our model is correct, trust me." as a response to a genuine inquiry into whether or not something is not working properly after a massive update.

Then that sucks for you. Because his works speaks for itself, why should I trust you know what you are talking about? Seriously... I am about ready to close this thread, its no wonder Yo-Yo is one of the only devs that tries to communicate guys.... you basically just stated you dont trust his word on what he does for a living, and has proven to do well many many times already... sorry... its just silly.

Hummingbird · December 18, 2015

Please let's not turn this into something it is not. I am not criticising Yo Yo here, infact my belief is that this is an issue he hasn't intended to be there, something his own charts seem to prove. Crumpp has mentioned this himself several times by now as well.

Also regarding Yo Yo's absence, perhaps he is just a wee bit busy, I mean its Christmas and there's a lot of content in the works at ED atm, so it's really pretty understandable. So let's just calm down and give him and ED a chance to properly look into this.

Meanwhile Crumpp and I will do some more tests, and I suggest other people who can do the same.

In the end we're just here to help, not to criticise based on percieved issues that might just be a mistake.

LFCChameleon_Silk · December 18, 2015

Yo-Yo does a fantasic job, I hope no ones trying to dispute that.

Hummingbird · December 18, 2015

Yo-Yo does a fantasic job, I hope no ones trying to dispute that.

Not at all!

As a matter of fact I believe this issue is unintentional as Yo Yo's own charts say it shouldn't happen. Just need to give him and ED some time to check it out properly.

Yo-Yo · December 18, 2015

Not at all!

As a matter of fact I believe this issue is unintentional as Yo Yo's own charts say it shouldn't happen. Just need to give him and ED some time to check it out properly.

If you mean these charts with coloured background, they were posted only as an illustration of the main principles of the aircraft turn ability in general and can not be considered a reference. The reason of it was the same I can not presume Crumpp's curves as reference.

For example, they both use the same linear Cl = k*AoA and CD_0 + A*CL^2 drag polar that can give max speed and climb rate but gives a lot of error at high AoA close to AoA_max. The real polars always have more or less ^4 member that is significant at high CL (or AoA).

Edited December 18, 2015 by Yo-Yo

ElGringo · December 18, 2015

Then that sucks for you. Because his works speaks for itself, why should I trust you know what you are talking about? Seriously... I am about ready to close this thread, its no wonder Yo-Yo is one of the only devs that tries to communicate guys.... you basically just stated you dont trust his word on what he does for a living, and has proven to do well many many times already... sorry... its just silly.

Nobody is denying that Yoyo does a fantastic job. But he is still human and, as such, can still make errors.

Telling us that all the evidence we presented to you are worthless because Yoyo is above making errors just makes you lose credibility, from my point of view.

You don' t HAVE to prove anything to us, sure... But you still should. Showing some respect to your user base would improve ED' s image.

Hummingbird · December 18, 2015

If you mean these charts with coloured background, they were posted only as an illustration of the main principles of the aircraft turn ability in general and can not be considered a reference. The reason of it was the same I can not presume Crumpp's curves as reference.

For example, they both use the same linear Cl = k*AoA and CD_0 + A*CL^2 drag polar that can give max speed and climb rate but gives a lot of error at high AoA close to AoA_max. The real polars always have more or less ^4 member that is significant at high CL (or AoA).

If you are refering to the drag bucket seen on laminar flow airfoils then that only shows up at low AoA's though. At high AoA's the laminar flow airfoil has no drag advantage over regular airfoils.

EDIT: I was refering to your latest chart with the grey background.

Edited December 19, 2015 by Hummingbird

NineLine · December 18, 2015

Nobody is denying that Yoyo does a fantastic job. But he is still human and, as such, can still make errors.
Telling us that all the evidence we presented to you are worthless because Yoyo is above making errors just makes you lose credibility, from my point of view.
You don' t HAVE to prove anything to us, sure... But you still should. Showing some respect to your user base would improve ED' s image.

You seem to have issues with seeing the point, so I will try one more time, Yo-Yo is and has been answering everything in this thread I never stated anyone is above making mistakes, but if he tells me it is fine, I am going to trust that because he general doest tell me anything unless he knows. So now unless you have something useful to add to this thread, on topic, you can just drop it.

Edited December 18, 2015 by NineLine

Hummingbird · December 18, 2015

Here's a drag polar comparison between a laminar and regular airfoil:

As can be seen at low AoA's the laminar flow airfoil has a definite drag advantage, but as AoA increases that advantage starts to disappear and is infact reversed near the critical AoA. Hence why laminar flow airfoils are great choice for improving range and straight line speed, but poor choice for improving maneuverability.

Curly · December 18, 2015

I don’t want to put words in Yo-Yo’s mouth but, what he’s seems to be saying is that the linear equations Crumps charts are based do not accurately predict lift coefficients at high angles off attack. the NACA came to this conclusion around 1947 while testing swept wings. Even ignoring other factors not taken into account by Crumps model, propeller effects, etc, the margin of error in his methodology is so great that it renders the predictive and comparative power of the equation moot in high alpha conditions.

Perkins and Hage is fine for most circumstances, but in the case being examined here a different approach is needed. The NACA, then NASA ran into similar issues as the performance of aircraft increased. Equations were no longer predicting experimental data. To reconcile this new methodologies were adapted, including Panel and Vortex Lattice methods.

Even if such methodologies were adapted to predict CL, CD, etc in Crump’s model. The predictive power of the model would be doubtful because it needs to take in to account, the variability of propeller efficiency and propeller downwash effects.

My interpretation of Yo Yo’s statements are, that there are limitations to the methodology used which say the flight model is wrong. The current test case exceeds the limitations of Crumps modeling and the more advanced modeling used in the sim would be a more accurate predictor of reality. Thus the 190 will stay the same until someone comes up with a proof or more accurate model which shows the current implementation is wrong.

Section lift curves are not linear particularly at high angles of attack and analytical solutions are not feasible.

Links to info on Vortex Lattice Method

http://www.dept.aoe.vt.edu/~mason/Mason_f/CAtxtChap6.pdf

http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/vlm/vlm.html

Edited December 18, 2015 by Curly

Crumpp · December 19, 2015

The predictive error of the method I am using is fine. It is as accurate as any other mathmatical model. The difference between single axis analysis and 6DOF equations of motion is -1.5 %.

Hummingbird · December 19, 2015

I don’t want to put words in Yo-Yo’s mouth but, what he’s seems to be saying is that the linear equations Crumps charts are based do not accurately predict lift coefficients at high angles off attack. the NACA came to this conclusion around 1947 while testing swept wings. Even ignoring other factors not taken into account by Crumps model, propeller effects, etc, the margin of error in his methodology is so great that it renders the predictive and comparative power of the equation moot in high alpha conditions.

Perkins and Hage is fine for most circumstances, but in the case being examined here a different approach is needed. The NACA, then NASA ran into similar issues as the performance of aircraft increased. Equations were no longer predicting experimental data. To reconcile this new methodologies were adapted, including Panel and Vortex Lattice methods.

Even if such methodologies were adapted to predict CL, CD, etc in Crump’s model. The predictive power of the model would be doubtful because it needs to take in to account, the variability of propeller efficiency and propeller downwash effects.

My interpretation of Yo Yo’s statements are, that there are limitations to the methodology used which say the flight model is wrong. The current test case exceeds the limitations of Crumps modeling and the more advanced modeling used in the sim would be a more accurate predictor of reality. Thus the 190 will stay the same until someone comes up with a proof or more accurate model which shows the current implementation is wrong.

Section lift curves are not linear particularly at high angles of attack and analytical solutions are not feasible.

Links to info on Vortex Lattice Method
http://www.dept.aoe.vt.edu/~mason/Mason_f/CAtxtChap6.pdf
http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/vlm/vlm.html

Again the propeller efficiency is mentioned, yet as proven the difference in propeller efficiency between the Dora & Mustang was less than 1%, and not even in the Mustang's favor. Again based on original source material.

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