A-10 stall behaviour in DCS is incorrect

[SCU]

The wing drop behaviour when reaching critical AoA or above, shouldn't happen in reality.

 

I had initially prepared a wall of text referencing mainly the A-10 official dash 1. But now I realised I could get into trouble for sharing it and just saved what I wrote in a text file. The draft I wrote includes excerpts of texts I quoted from the manual, and the sections/pages of them.

 

If it's ok I will share here the draft I wrote but if not, well I will just have to make do with videos. I can share a good number of videos which I hope they are evidence enough for you.

Edited October 7, 2016 by SCU

[NineLine]

It's safe to assume that all those that need to have it, have the -1 already.

 

Post tracks/vids and info on conditions of your tests, and how you think they differ from how it works in the real world. You can quote official sorces, and post what you are quoting from, but no, dont post the -1 again.

[SCU]

Okay then..

 

 

(Cockpit)

 

(External view of the same maneuver)

 

These videos are from airshows as you can see, the jet is obviously clean & probably on minimum fuel for top performance. I'll post track later with similar setup and good conditions for comparison.

 

You can see how the plane is jerked with a buffeting behaviour and no wing drop or rolling which is how it's described in the manual (so shameless of me :lol:). This would probably work with the light weight setup in the sim, but only because it's a sudden move and doesn't give time for the wing dip coding in the flight model to set in or something, I'm not a coder I don't know, but trying to sustain it you will definitely lose control. If the plane IRL rolls on higher than critical AoA's I don't think the pilot would risk such a move at such low altitude close to watchers.

 

(HUD tape)

 

Brief hard pull up, but you can see if you look closely how as the chopped tone sets in there is buffeting of the airplane and only that.

 

Buffeting is more clear here:

 

I counted about 9 seconds of chopped tone in this one. I don't think that's possible in DCS with perfect conditions and lightest configuration. You even don't get any stall tones at the airspeeds in this specific video (above mach 0.7) with the same pull, you just spiral out of control until relaxing the stick.

 

(I'd lower the headphones volume before watching)

The first 12 seconds or so are mostly riding the chopped tone at slow speeds, again unlike in DCS, no wing stall or dropping. Also this is a combat operation recording, I don't know how that makes a difference but I thought I'd let you know. The fuel is really low (13:45, below bingo) as you'll find out as you watch the video later on (it's 20 mins long).

 

I'm not sure if weight should affect stall behaviour directly. Genrally (shameless plug i know) you should read the stall & departure sections clearly from the manual and pay attention to the details talking about sideslip and yaw-roll coupling.

 

There's still more videos where those came from, I haven't shared the dogfight ones yet, but the post is getting too long already, maybe I'll share em laters and maybe some tracks too.

[NineLine]

Perhaps try showing yourself trying these same maneuvers in the sim? If you can display your controls in the vids, if you can that would probably helpful too.

[SCU]

Complete with split S at low altitude & crash in the end. It did show some uncommanded roll before the crash.

 

Note all the uncommanded rolls throughout the track. Like I said, some of the sudden jerks will not go out of control due to their fast and brief nature.

 

http://forums.eagle.ru/attachment.php?attachmentid=146945&stc=1&d=1472063835

 

Conditions:

http://forums.eagle.ru/attachment.php?attachmentid=146946&stc=1&d=1472064169

Stall Test1.trk

[NineLine]

Complete with split S at low altitude & crash in the end. It did show some uncommanded roll before the crash.

 

Note all the uncommanded rolls throughout the track. Like I said, some of the sudden jerks will not go out of control due to their fast and brief nature.

 

http://forums.eagle.ru/attachment.php?attachmentid=146945&stc=1&d=1472063835

 

Conditions:

http://forums.eagle.ru/attachment.php?attachmentid=146946&stc=1&d=1472064169

 

Do you have any curves on your controls, and what controls are you using as well, just for perspective...

[SCU]

I do have curves, and it's TM warthog.

[SCU]

So? Anyone at ED have anything to say about this? Am I wrong, right and if so will anything be change about it?

[David OC]

So? Anyone at ED have anything to say about this? Am I wrong, right and if so will anything be change about it?

 

You have tried this in the sim right?

 

No ordnance (including the gun ammo) with minimum fuel just like for this airshow in the video?

 

I'm able to be back on target in 30 seconds with this load out.

[SCU]

I'm able to be back on target in 30 seconds with this load out.

 

I'm sorry what?

Edit: oh I read it again. I wasn't talking about turn radius or turn rate or time taken until you reverse your heading.. I'm talking about high Alpha performance. The wing shaking and dropping behaviour when you're attempting to ride the chopped stall warning tone. It's not right, per the real jet's -1 manual, videos and an actual pilot who said that on the famous reddit Q&A.

Edited August 26, 2016 by SCU

[David OC]

I'm sorry what?

Edit: oh I read it again. I wasn't talking about turn radius or turn rate or time taken until you reverse your heading.. I'm talking about high Alpha performance. The wing shaking and dropping behaviour when you're attempting to ride the chopped stall warning tone. It's not right, per the real jet's -1 manual, videos and an actual pilot who said that on the famous reddit Q&A.

 

The sim is a lot different to the real world because in the aircraft you are experiencing the Gs to your body. It's a lot more of a work out then on my CH joystick at home, and the feeling in the cockpit is how many Gs? Pull this hard when your under 2Gs is a lot different then sitting at a desk top PC. You need a pilot to take more of a scientific a approach to the sim and fly by the numbers to get a more of an accurate account in the the sim. Others have tried this and the A10 hits the numbers.

[SCU]

The sim is a lot different to the real world because in the aircraft you are experiencing the Gs to your body. It's a lot more of a work out then on my CH joystick at home, and the feeling in the cockpit is how many Gs? Pull this hard when your under 2Gs is a lot different then sitting at a desk top PC. You need a pilot to take more of a scientific a approach to the sim and fly by the numbers to get a more of an accurate account in the the sim. Others have tried this and the A10 hits the numbers.

 

Those pilots can keep up with up to 9 G's. So the max G limit for an A-10 of 6.5 or so isn't really gonna stop them from pulling more (which they do). As I said, an actual A-10C pilot tried DCS's A-10C and has commented on reddit that the real jet is more forgiving at high alphas.

 

I also have proof for what I'm saying from the real -1, it's all ready in a text file draft on my computer but unfortunately I can't share it here as Sith said. I have reference to lots of real life videos and HUD tapes that prove what I say. Even though I can't "feel the G's" through watching those videos, it's still clear that the stalling behaviour we have in DCS is incorrect.

 

Suffice to say there is no mention in the -1 whatsoever to the stall behaviour we have in the sim.

 

 

Try the maneuver between 0:29 & 0:41, which is a solid 12 seconds of chopped stall tone, in DCS. You can try it with the lightest weight possible, clean config & the most ideal conditions and you will lose.. you will lose control and your wings will keep droping.

 

Granted this A-10 has a decent amount of fuel (obviously so he can RTB after training) and carries 1 AIM 9 at least.

[SCU]

 

I doubt that those guys felt the G's...

[David OC]

There is no full sim in the world I believe can fully simulate the edge of envelope, close but not completely. You need to go out and fly a real aircraft and each of those aircraft will be different also. I know it's hard but you are taking about a very hard line in the unknown realm of physics. That I would not want Yo-Yo to try and explain...

[SCU]

There is no full sim in the world I believe can fully simulate the edge of envelope, close but not completely. You need to go out and fly a real aircraft and each of those aircraft will be different also. I know it's hard but you are taking about a very hard line in the unknown realm of physics. That I would not want Yo-Yo to try and explain...

 

I understand and accept that sims can't be fully simulated. But when something in the sim doesn't actually happen in real life that is where a line should be drawn. There is nothing hard or unknown about the A-10's stall & departure performance, it's all out there for anyone to read about. I'm not claiming to be an A-10 engineer or a pilot. Heck I'm not even either of those without relation to the A-10, I'm only stating what I noticed with comparison to the real documents and recordings.

[David OC]

I understand and accept that sims can't be fully simulated. But when something in the sim doesn't actually happen in real life that is where a line should be drawn. There is nothing hard or unknown about the A-10's stall & departure performance, it's all out there for anyone to read about. I'm not claiming to be an A-10 engineer or a pilot. Heck I'm not even either of those without relation to the A-10, I'm only stating what I noticed with comparison to the real documents and recordings.

 

I do understand, but to move the FM say 0.01 in the FM (physics) world to perhaps make it better or make it worse, yes this could happen and make things worse when playing this close. How much work do you think it would take? How long would this take? Let me just say it's not a 5 minute job to try and move it, it could very well take years in my opinion.

 

Let me just say this doesn't affect my enjoyment of the A10 in sim at all. I've never really noticed.

Edited August 26, 2016 by David OC

[SCU]

Ok, I'm not a programmer either (damn I'm starting to look like an unemployed ignorant, but really I'm not), but how hard can it be to just stop the plane's wing dip spiral tendencies at high AoA? Maybe even postpone it to some higher AoA value which still wouldn't be realistic but would be better than what we have.

[SCU]

Let me just say this doesn't affect my enjoyment of the A10 in sim at all. I've never really noticed.

 

No offence, but that's due to you not really caring to how the real guys do it. I've taken interest in watching how the real pilots use this machine (and others I've tried to fly too) and reading about their real life procedures. They really do take their planes to the edge of the envelope and still remain within the safety margin. It's just how these military machines were built.

[NineLine]

No offence, but that's due to you not really caring to how the real guys do it. I've taken interest in watching how the real pilots use this machine (and others I've tried to fly too) and reading about their real life procedures. They really do take their planes to the edge of the envelope and still remain within the safety margin. It's just how these military machines were built.

 

Yo-Yo is a busy guy, if anything comes of this it will be updated here, I plan on trying some tests myself this weekend.

 

As for how hard it is to fix something? Well if there is incorrect data causing this, then you need the correct data. You cant change the results you have to change what causes it, if that makes sense. If there was an issue then it could be incorrect data, or an error in how that data was input.

 

One thing to be mindful of, and I havent had a chance to look at your track, hoping this weekend, is that our controls, movements and such differ greatly from the real thing, meaning you could be throwing the stick harder than they are able to, causing weird things to happen, keep an eye on that when you perform maneuvers, and even check your curves to make sure that isnt causing certain movements to be too strong.

[SCU]

Yo-Yo is a busy guy, if anything comes of this it will be updated here, I plan on trying some tests myself this weekend.

 

As for how hard it is to fix something? Well if there is incorrect data causing this, then you need the correct data. You cant change the results you have to change what causes it, if that makes sense. If there was an issue then it could be incorrect data, or an error in how that data was input.

 

One thing to be mindful of, and I havent had a chance to look at your track, hoping this weekend, is that our controls, movements and such differ greatly from the real thing, meaning you could be throwing the stick harder than they are able to, causing weird things to happen, keep an eye on that when you perform maneuvers, and even check your curves to make sure that isnt causing certain movements to be too strong.

 

Thanks.

 

I have a curve of positive 20 for pitch in A-10C. I'm making my movements 'weaker' by this. When you watch the track I shared you can watch the controls indicator to see how hard I was pulling, but I was generally trying to be careful not to exceed max AoA by much.

 

I also read that A-10 pilots were instructed to "pull the stick into their laps" in specific situations.

[NineLine]

 

I also read that A-10 pilots were instructed to "pull the stick into their laps" in specific situations.

 

 

I dont doubt that, all I am saying is that the effort to pull the stick into their laps could be quite different for us, if you know what I mean.

[whiteside]

Absolutely do not want to ruffle anyones feathers in regard to the great sim that has been produced here but weather it meets book numbers or not I've always thought that the DCS A10C drops a wing too easily when in maneuvering flight. Watch any Hog demo vid and then go side by side trying to reproduce it. I'm pretty sure you can't or at least I can't.:) It would sure give it more of a "SOFT" feel instead of having such an abrupt tip stall. In my experience, aircraft are designed with more ability to withstand the pilot pulling on it than is demonstrated here.

That's just my two cents and I sure would fly the Hog more often if it flew the way I know it should. Otherwise, fantastic job on this aircraft!

[Goblin]

It's been a while since I last flew the A-10C in DCS, but I know a thing or two about stalls...

 

The general stability in pitch, which greatly affects the ability to balance the aircraft in high AoA, is affected by center of gravity (CG). An aircraft with CG aft will be less stable in pitch, meaning that a involontary increase in AoA won't be dampened out aerodynamically and must be corrected manually. I guess emptying the gun will make the Hog less stable..?

 

Also, wingdrop can occur on any aircraft if flown uncoordinated (slipping).

 

The A-10C has a stability augmented flight control system. Normally this will help stabilizing (duh!) high AoA flight. Maybe just the stabilizing algorithms needs a tune in DCS?

 

Just a thought...

[311Gryphon]

An aircraft with CG aft will be less stable in pitch, meaning that a involontary increase in AoA won't be dampened out aerodynamically and must be corrected manually.

 

"Damped" Dampened would mean it got wet.

 

Sorry, I couldn't help it. A few of my friends have a running gag about the usage of "damped" versus "dampened".

 

Anyway, I tend to agree with the few here who have posted that they don't think it is quite correct. I'm glad to see some deliberate work going on with this. I do think the A-10C is probably far and away the most accurate combat sim on the planet, at least available to weekend warriors like me. I also think it is a dream to fly with whatever inaccuracies it has. However, I've always felt like it was a bit too limited in performance with or without a load out. I've never flown one, but you can look at flight characteristics and see that they don't quite match up with what real pilots are able to make the plane do. That isn't all about the flight controls or the G's (although I'm certain those matter). At certain flight parameters the plane should do X. If it doesn't, then something may be off.

 

Anyway, just thought I'd throw my two cents in. I think most of the community is overwhelmingly happy with the A-10C so most of us just want to know that it is intentionally being looked at. If nothing comes of it, no worries. If something does, it will undoubtedly remain at the top of the food chain of commercially available combat flight simulators.

[Pocket Sized]

I guess emptying the gun will make the Hog less stable..?

 

[. . .]

 

The A-10C has a stability augmented flight control system. Normally this will help stabilizing (duh!) high AoA flight. Maybe just the stabilizing algorithms needs a tune in DCS?

 

Just a thought...

 

Try taking off with no gun ammo and you'll see you need a huge amount of nose down trim. It's also much harder to keep the solid tone while turning. A-10C only has pitch and yaw SAS. This is mainly a roll stability issue. [break]

 

I feel like washout (wingtips pointed down slightly) would have a pretty massive effect here. Does the real thing have it in the wings or are the ailerons canted up a bit to substitute for washout?