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Someone can correct me if I am wrong, but I believe that an aircraft should stall regardless of speed if the critical AoA of the wing is exceed. I am also pretty sure that ww2 aircraft tend to have critical AoA pretty much universally of about 15-16 degrees, perhaps 20 with slats.

 

I was watching a track in tacview today and noticed that aircraft were routinely pulling 30-40 degrees AoA. Yes, I know tacview has made errors in the past in this game, I know of no way to check this in game. 

 

Anyone know anything about this?

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Its about stalls being modelled in a lets say very simplified way. So it is easily possible to control aircraft at angles of attack larger than the stalling angle of attack. This was possible in real life too, with some aircraft, but not as easily as in game.

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Posted (edited)

A bit more detail might help  to determine whether this is an issue with the game, or with Tacview. Or neither/both.

Edited by AndyJWest

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According to the BoX techspecs for each aircraft, the 109s reach a 20 degree stall AoA in flight configuration (F+G up) with 18-19 degrees being typical for the single seat fighters. Presumably this is the angle at which lift starts to reduce, rather than that at which the wing stops generating lift altogether, in which case is it fair to assume that control could be maintained for a couple more degrees, maybe a little more with washout?

 

Then there is the question of what angle Tacview is actually measuring, or for that matter what angle is being measured in the techspecs.....

 

 

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1 hour ago, JtD said:

Its about stalls being modelled in a lets say very simplified way. So it is easily possible to control aircraft at angles of attack larger than the stalling angle of attack. This was possible in real life too, with some aircraft, but not as easily as in game.

How simplified? I tested the Yak just now and it can hold 30 degrees.

tac.png

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Just now, 307_Tomcat said:

I think that game is more forgiving that RL.

 

Looks like it is. It's easy to recover from full spins, too. Not only they seldom happen but I never had to cut throttle for that.

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I think fm needs a big tunn. Things like this. Mass and energy retention etc... 

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Posted (edited)
On 4/13/2019 at 9:13 PM, E69_geramos109 said:

I think fm needs a big tunn. Things like this. Mass and energy retention etc... 

Great insight. I'm curious what Sims people are playing that model flight and engines perfectly. Would love to try them. 

Edited by JonRedcorn
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Posted (edited)
1 hour ago, JonRedcorn said:

Great insight. I'm curious what Sims people are playing that model flight and engines perfectly. Would love to try them. 

No sim models everything perfectly but there are sims that model things better than Il2. 

Stall behavior does need improvement along with many other things. 

 

Il2 is a great game but it can always be better and really needs a tune up in some areas. No point in blindly defending a product when you know there is room for improvement.

 

If you don't push for change then change won't happen, they'll just say it's good enough and move onto something else.

 

EDIT: I'm not saying you're blindly defending them but I know there are a few people on these forums who do. They think Il2 is the greatest thing in the world and the devs can never be wrong.

Edited by Legioneod
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1 hour ago, Legioneod said:

I know there are a few people on these forums who do. They think Il2 is the greatest thing in the world and the devs can never be wrong.

 

I think you may be exaggerating just a wee bit there... LoL

 

However I will say some peoples expectations are very unrealistic for what they are paying for 

 

Cheers, Dakpilot 

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1 minute ago, Dakpilot said:

 

I think you may be exaggerating just a wee bit there... LoL

 

However I will say some peoples expectations are very unrealistic for what they are paying for 

 

Cheers, Dakpilot 

Not really, I know a few people on here that blindly defend the devs and don't accept it when people criticize Il2.

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2 minutes ago, Legioneod said:

Not really, I know a few people on here that blindly defend the devs and don't accept it when people criticize Il2.

 

No, you actually don't.

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2 minutes ago, BraveSirRobin said:

 

No, you actually don't.

Not gonna argue. Just let it be.

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Just now, Legioneod said:

Not gonna argue. Just let it be.

 

No, I'm not just gonna let it be.  That comment by you is complete BS.

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Before this degenerates into just another pointless exercise in turn-based forum combat, I think we need to ascertain whether Tacview is actually reporting what the game is doing. Which at least in principle, shouldn't be that difficult. For an initial exercise, can someone who has Tacview installed (I don't) do a little test: put a P-40 on a runway, and then see what Tacview shows the AoA as being for the initial part of the takeoff run, before the tailwheel lifts off. The new Motion Support API says that the P-40 sits at 14.3° to whatever datum is being used at rest, and unless there is something seriously wrong with my thinking (not entirely impossible) that should be close to the same angle as the AoA reported with the tailwheel on the runway. It may not be exactly the same, as the API datum probably doesn't coincide with the wing chord datum, but should give a sense of whether Tacview is in the right ballpark, at least for that situation. I suggest doing this with the P-40, as it sits very nose-high, making the angle in question larger, and accordingly any difference between datum and wing chord less in proportion.

 

I have a suspicion, based on the supposed AoA values quoted, and on the data shown in Fumes' Tacview screenshot (A Bf 109 at 40.5° AoA!!) that this is a simple conversion error somewhere, rather than an intrinsic fault with IL-2 GB. There are other possible tests to carry out, but we should start with the obvious first...

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Posted (edited)

https://forum.il2sturmovik.ru/topic/8361-flight-model-корректна/?do=findComment&comment=677752

 

TLDR: AnPetrovich flies real aircraft and performs a lot of spins in them. Once he was flying Yak-52 and was intentionally pulling high AoAs and he quickly corrected spins by the very same actions as in BoX. Moreover, the behavior was so close that it gave him impression as if he was flying Yak-1 or LaGG-3 in the game.

 

If you guys feel that the spin behavior is simplified, is it based on your real life flying experience? I'm curious since I don't have one and it would be interesting to hear opinions of people who fly real aircraft. 

Edited by Arthur-A

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1 hour ago, AndyJWest said:

Before this degenerates into just another pointless exercise in turn-based forum combat, I think we need to ascertain whether Tacview is actually reporting what the game is doing. Which at least in principle, shouldn't be that difficult. For an initial exercise, can someone who has Tacview installed (I don't) do a little test: put a P-40 on a runway, and then see what Tacview shows the AoA as being for the initial part of the takeoff run, before the tailwheel lifts off. The new Motion Support API says that the P-40 sits at 14.3° to whatever datum is being used at rest, and unless there is something seriously wrong with my thinking (not entirely impossible) that should be close to the same angle as the AoA reported with the tailwheel on the runway. It may not be exactly the same, as the API datum probably doesn't coincide with the wing chord datum, but should give a sense of whether Tacview is in the right ballpark, at least for that situation. I suggest doing this with the P-40, as it sits very nose-high, making the angle in question larger, and accordingly any difference between datum and wing chord less in proportion.

 

I have a suspicion, based on the supposed AoA values quoted, and on the data shown in Fumes' Tacview screenshot (A Bf 109 at 40.5° AoA!!) that this is a simple conversion error somewhere, rather than an intrinsic fault with IL-2 GB. There are other possible tests to carry out, but we should start with the obvious first...

I'll have a look tomorrow and see. I know tacview used to have pretty large errors in data but not sure if that was ever fixed.

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2 hours ago, Arthur-A said:

https://forum.il2sturmovik.ru/topic/8361-flight-model-корректна/?do=findComment&comment=677752

 

TLDR: AnPetrovich flies real aircraft and performs a lot of spins in them. Once he was flying Yak-52 and was intentionally pulling high AoAs and he quickly corrected spins by the very same actions as in BoX. Moreover, the behavior was so close that it gave him impression as if he was flying Yak-1 or LaGG-3 in the game.

 

If you guys feel that the spin behavior is simplified, is it based on your real life flying experience? I'm curious since I don't have one and it would be interesting to hear opinions of people who fly real aircraft. 

Ok then to be full flaps on a P47 at 50kph nose up is well modelled. I guess he manage to do that on the yak52

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@E69_geramos109, a simple question: would you rather this thread discussed a possible flaw in the FM based around verifiable and measurable data, or that it turned into yet another pointless evidence-free whinge-fest? Because if you want the latter, you are liable to have the thread to yourself soon, as I have no interest in gathering data just so people can ignore it, and drown out any useful information with the same old tiresome evidence-free moaning we've already seen a hundred times before.

 

@Legioneod. Thanks,  that would be most helpful. 

 

If anyone else is interested in gathering data on this, I have a few more ideas, but I'll leave them for now, until we get confirmation of the P_40 on-runway data.

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Posted (edited)
3 hours ago, AndyJWest said:

@E69_geramos109, a simple question: would you rather this thread discussed a possible flaw in the FM based around verifiable and measurable data, or that it turned into yet another pointless evidence-free whinge-fest? Because if you want the latter, you are liable to have the thread to yourself soon, as I have no interest in gathering data just so people can ignore it, and drown out any useful information with the same old tiresome evidence-free moaning we've already seen a hundred times before.

 

@Legioneod. Thanks,  that would be most helpful. 

 

If anyone else is interested in gathering data on this, I have a few more ideas, but I'll leave them for now, until we get confirmation of the P_40 on-runway data.

I dont want to discuss that. Just saying that for some people everything is fine no matter what we have. I think is evident that the Fm has some flaws discussed and well documented in other posts (I posted some of them). And I think there is nothing wrong for saying it. 

 

Sorry for the offtopic. 

Edited by E69_geramos109
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Posted (edited)

P-40 stationary on runway in Tacview shows pitch at 14.4 degrees, AoA at zero degrees. 

 

(I am not an expert on this use of this, just messing around with the free version.)

Edited by unreasonable

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The next sogical step to me would be to see if the P39 is able to get to those height AoA numbers. 

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2 hours ago, unreasonable said:

P-40 stationary on runway in Tacview shows pitch at 14.4 degrees, AoA at zero degrees. 

 

(I am not an expert on this use of this, just messing around with the free version.)

 

I'm not asking for the AoA when it is stationary (that is a meaningless figure). What I want is the figure that Tacview gives  while the aircraft is moving, but before the tailwheel lifts off the ground.

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Just for you for info but also to put things in perspective:

 

Professional flight simulators are classified in different categories. First you have two main categories:

 

Flight Training Devices (Level 4, 5, 6, 7) Levels are sub-categories that increase with fidelity of the aerodynamic modelling and cockpit functions to represent one specific aircraft in detail. These are static platforms.

 

Full Flight Simulators (Level A, B, C, D) Levels are sub-categories that increase with the number of degrees of freedom of the motion platform from three to six, angle of vision of the display, sound acoustics quality, visual effects etc..

 

Now how much you think costs one simulator cabin of the type FFS Level D (The best of all) ? Depends if civil or military.

  • For a B787 civilian passenger aircraft you need to spare about 17 Million US$
  • For a military helicopter like the Eurocopter Super Puma it is just small change (for the military budgets) at 40 Million US$.

With IL2 for less than 100 dollars you have a military simulator not for one but for 30 planes, with UHD visuals , VR, sounds and acoustics, visual effects, multiple fighter synchronized server connection, realistic cockpits with functioning instruments, aerodynamics, engine and plane dynamic structural modelling, gunfire, and bombing, rockets simulation, meteorology weather simulation etc. etc. 😮

 

Anybody has a complaint ?.......:hunter:

 

Well done devs. Keep on the excellent job you are doing.🙂

 

 

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I've now downloaded the latest free Tacview trial version, and done the test I wanted myself (though it will still be useful to get independent corroboration). I can confirm that Tacview is correctly reporting the AoA as about the same angle as nose-up pitch, when the aircraft is moving along the runway with the tailwheel down. This would seem to rule out at least one possible source of error, though it is by no means sufficient to eliminate the possibility that there is a reporting error in other situations. 

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Posted (edited)
19 hours ago, IckyATLAS said:

Just for you for info but also to put things in perspective:

 

Professional flight simulators are classified in different categories. First you have two main categories:

 

Flight Training Devices (Level 4, 5, 6, 7) Levels are sub-categories that increase with fidelity of the aerodynamic modelling and cockpit functions to represent one specific aircraft in detail. These are static platforms.

 

Full Flight Simulators (Level A, B, C, D) Levels are sub-categories that increase with the number of degrees of freedom of the motion platform from three to six, angle of vision of the display, sound acoustics quality, visual effects etc..

 

Now how much you think costs one simulator cabin of the type FFS Level D (The best of all) ? Depends if civil or military.

  • For a B787 civilian passenger aircraft you need to spare about 17 Million US$
  • For a military helicopter like the Eurocopter Super Puma it is just small change (for the military budgets) at 40 Million US$.

With IL2 for less than 100 dollars you have a military simulator not for one but for 30 planes, with UHD visuals , VR, sounds and acoustics, visual effects, multiple fighter synchronized server connection, realistic cockpits with functioning instruments, aerodynamics, engine and plane dynamic structural modelling, gunfire, and bombing, rockets simulation, meteorology weather simulation etc. etc. 😮

 

Anybody has a complaint ?.......:hunter:

 

Well done devs. Keep on the excellent job you are doing.🙂

 

 

I mean this is just a bogus comparison

 

Most of the cost you just compared deals with the motion platform. Second, professional grade things, especially when they are possibly for the government, have tons of other costs that have [edited] to do with the fidelity of the sim necessarily. And then there is rather obvious fact that sims made for gaming are intended to be MASS MARKETED, and their costs vary accordingly. 

 

VBS3, the US Army's sim for training is [edited]. Each copy costs more than 3000 dollars. The computers the army uses to play the game on, are more expensive than my desktop computer by about 4 times, and have less than a quarter the performance. The civilian copy of Arma 1, 2, or 3, all of which are superior especially with mods, cost 60 dollars.

 

What is more, we are talking about simple shit here, simple for aero anyhow. Getting stall AoA correct is something sims have been doing since the late 90s.

Edited by SYN_Haashashin
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3 minutes ago, Fumes said:

....simple shit...

 

OK, that's it. I'm done here. Since it seems self-evident that people would rather engage in abusing the developers than in actually providing verifiable repeatable data, I am going to play no further part in this discussion. I may well conduct further investigations (I've already made some possibly relevant findings), but will do so without the 'assistance' of this data-free whinge fest.

 

Anyone actually interested in conducting further tests, rather than engaging in pointless repetitive going-nowhere discussions is welcome to contact me by PM. Don't bother to do so unless you can confine the discussion to actual data collection though, as I'm not the slightest bit interested in hearing the same old nonsense yet again.

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Posted (edited)
7 minutes ago, AndyJWest said:

 

OK, that's it. I'm done here. Since it seems self-evident that people would rather engage in abusing the developers than in actually providing verifiable repeatable data, I am going to play no further part in this discussion. I may well conduct further investigations (I've already made some possibly relevant findings), but will do so without the 'assistance' of this data-free whinge fest.

 

Anyone actually interested in conducting further tests, rather than engaging in pointless repetitive going-nowhere discussions is welcome to contact me by PM. Don't bother to do so unless you can confine the discussion to actual data collection though, as I'm not the slightest bit interested in hearing the same old nonsense yet again.

Who is throwing shade at the devs? I agree more testing is needed. We dont actually know if there is a problem here yet.

 

But wings stalling at a certain AoA is indeed simple shit for aero. Its not simple in general, but its pedestrian compared to some of the much more complicated things this and other sims do. Sims for twenty years ago could do it. If we do have a problem here its a fairly big deal.

 

What we dont need, which is in line with your call for more testing and discussion, is people coming in here and making appeals to their supplicancy to the developers and passive aggressively telling us to all be thankful for what the gods have deigned to give us. 

Edited by Fumes

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For the P-47D flaps issues...

 

Flaps on or off it's unlikely that P-47D's wing would generate enough lift at such low speed and high AoA. The Jug is not Antonow An-2... just compare wings area and weight to see why.

At such low speed the big prop and (2600hp no less) engine's gyroscopic forces should flip the plane after few moments.

And finally from the very P-47D manual:

P-47D_stalls.thumb.jpg.34bf3a1323d0e0d8190689bb801779ce.jpg

 

All these make current P-47D flaps behavior at low speeds unlikely.

There is also the hydraulic synchronization of flaps deployment; I don't have a link now but I recall they should be used carefully to not provoke any  asymmetrical deployment failure.

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2 hours ago, Fumes said:

 

But wings stalling at a certain AoA is indeed simple shit for aero. 

 

Indeed.  Maybe you should have checked whether tacview properly calculates AoA before starting this thread.  It doesn’t.

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Posted (edited)
33 minutes ago, BraveSirRobin said:

 

Indeed.  Maybe you should have checked whether tacview properly calculates AoA before starting this thread.  It doesn’t.

 

Tell me that @BraveSirRobin !!!  

I was starting to feel really bad about it and even considering buy TACVIEW, after shouting out allover the places IL-2 is my preferred flight simulation !...

 

Can you be more specific regarding your affirmation ? Thx !

Edited by jcomm

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6 minutes ago, jcomm said:

 

Tell me that @BraveSirRobin !!!  

I was starting to feel really bad about it and even considering buy TACVIEW, after shouting out allover the places IL-2 is my preferred flight simulation !...

 

Can you be more specific regarding your affirmation ? Thx !

 

Look at the link Matt posted.

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54 minutes ago, BraveSirRobin said:

 

Indeed.  Maybe you should have checked whether tacview properly calculates AoA before starting this thread.  It doesn’t.

Do try to make sense when you type.

 

I stated in the first post that tacview might not be right. The point of this thread was to explore what was going on. Hence my first post ending in a question. 

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Posted (edited)
17 minutes ago, BraveSirRobin said:

 

Look at the link Matt posted.

 

Thx, I had missed that one...

 

So TACVIEW takes geometric AoA, not aerodynamic…  I still remember when around 2006 "our" beloved "icidence" and "washout" records were "robbed" from MSFS flight dynamics between fs9 and fsx… They started to take geometic AoA instead. Washout went out too...

 

and… @Fumes, it was good for you to start the thread, but it would also be great to see you happy that it isn't actually - just - an IL-2 limitation...

Edited by jcomm

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Just now, Fumes said:

Do try to make sense when you type.

 

I stated in the first post that tacview might not be right. 

 

 

And it’s not.  Problem solved!

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2 minutes ago, BraveSirRobin said:

 

 

And it’s not.  Problem solved!

Imagine if we could have figured it out without your input. Now THAT would be a problem solved.

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49 minutes ago, Fumes said:

Imagine if we could have figured it out without your input. Now THAT would be a problem solved.

 

Yes, I think it would have been great if you could have figured it out on your own.  And yet, here we are...

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