Neglected/incomplete flight model?

[Aluminum Donkey]

Greetings,

 

 

The 21 is a nice module and all, but seems to have problems with its flight model. From the "digital stall" effect, to the lack of roll inertia, to the general lack of consistency across various DCS updates--it seems to fly like an entirely different aircraft every time DCS gets updated. It makes me wonder if the real thing flies anything like the DCS module, despite Leatherneck/M3 LLC's marketing to the contrary, including their bragging about having a real MiG-21 pilot on the dev team :)

 

 

So, is the MiG-21 still essentially a pre-release version, despite having been available for quite a while now? Is it still being refined, or is it essentially abandonware?

In other words, is M3 LLC still in business at all and working on finishing their so-close-yet-so-far module, or is what we see what we get, too bad so sad and thanks for your cash?

 

 

AD

[Auditor]

Oh yeah, I think everyone notices it. It's been open on the bugtracker for almost a year. It straight up becomes loony tunes physics once you reach low-speed.

https://leatherneck-sim.mantishub.io/view.php?id=689

 

I almost think its gotten worse since the migration from 1.5.

 

In terms of who is still working on the Mig-21 now that development of the CE2 is in full-swing, I'd like to know that too!

Edited September 8, 2018 by Auditor

[Aluminum Donkey]

Oh yeah, I think everyone notices it. It's been open on the bugtracker for almost a year. It straight up becomes loony tunes physics once you reach low-speed.

https://leatherneck-sim.mantishub.io/view.php?id=689

 

I almost think its gotten worse since the migration from 1.5.

 

In terms of who is still working on the Mig-21 now that development of the CE2 is in full-swing, I'd like to know that too!

 

 

They really, really have to sort this out. Switches and buttons that work like the real thing are nifty and all that, but it's a *flight* sim, and the flight model feels very incomplete to me whenever I start putting some gusto into the stick.

I'm also not sure what kind of airplane it's supposed to be simulating :) Since the flight characteristics change wildly from time to time with various updates, it seems like they can't decide what kind of plane they're simulating! The problem with this is, when I'm flying the module, I'm always thinking, "Ok... this is kinda cool, but so what? Is this really a half-decent MiG-21 simulation, or a half-arsed one, or a half-brained one, or a half-baked one, or a... you know.

Stability changes.

Roll rate changes (a lot!!).

Damping/oscillation tendency changed a lot.

One iteration, it flies like a FBW aircraft.

Next one, it's wobbling around almost like a WW2 fighter, minus the P-factor!

Can't M3 agree for once on what a MiG-21 actually flies like, finish the flight model, and release it once and for all, instead of messing around for ages?

 

 

AD

[Auditor]

Very much agreed, and would also like to echo sentiments about finalizing the flight model or at least getting confirmation about what would be the roadmap to finalizing it.

 

In terms of its wobbly nature, I believe that was a mistake that was rectified sometime. Also, it would receive exceptionally good handling if SAU stabilize were functioning.

[zcrazyx]

If you wanna see a meme, get a huey to ram your vert stab and rudder off until there is only a little bit of the rudder left, take off and note that it still has most of the rudder authority with only 10% of the surface.

[Auditor]

:lol: That's hilarious.

[Skarp]

The Mig21 flight dynamics are modeled very well. This isn’t a Hershey bar winged aircraft , it’s stall , roll, turn characteristics ect will be different in many ways. One example is because the wing is so small you’re not going to have one wing stall before the other except in extreme yaw angles and cause you to roll over into a spin. The Mig 21 is so good take some aerodynamic courses and you’ll see it’s spot on.

[Auditor]

The Mig21 flight dynamics are modeled very well. This isn’t a Hershey bar winged aircraft , it’s stall , roll, turn characteristics ect will be different in many ways. One example is because the wing is so small you’re not going to have one wing stall before the other except in extreme yaw angles and cause you to roll over into a spin. The Mig 21 is so good take some aerodynamic courses and you’ll see it’s spot on.

 

Now, do you say that knowing that it has a hard coded 2G limit at low speeds that the devs acknowleged is unrealistic that you can check in the bugtracker or do you say that because it "feels right" and that's good enough for you?

 

Whether you like it is separate to if its accurate

Edited September 23, 2018 by Auditor

[Skarp]

I don’t seem to encounter this problem you describe.

[pepin1234]

I feel good with the Mig-21 flight model.

 

Maybe the behavior below 500km/h with Afterburner is not that good

[Skarp]

Now, do you say that knowing that it has a hard coded 2G limit at low speeds that the devs acknowleged is unrealistic that you can check in the bugtracker or do you say that because it "feels right" and that's good enough for you?

 

Whether you like it is separate to if its accurate

 

There is no 2g limit if that were the case a Cessna 150 would have better performance

[bkthunder]

There is no 2g limit if that were the case a Cessna 150 would have better performance

 

There is. Instead of generating confusion by telling people they are wrong (when, in fact, you are wrong) why don't you grab the MiG-21 and verify for yourself? He even gave you the link to the bug report which has been ACKNOWLEDGED by the developer.

[FSKRipper]

Hm, I'm not sure what's going on here. So the following statement from Rudel:

 

"The programmer for the flight model has stressed it will remain as is. As stated before in previous posts, actual real-time flight data recordings from a Serbian MiG-21Bis (75B) were presented to Eagle Dynamics as requested. There were no objections towards the data presented and all discrepancies in existing documents were explained. Fret not, other bugs will continue to be fixed though."

 

tells at least me that ED's FM guys found no serious stuff after checking it besides from some minor bugs that will be fixed, right?

 

This would mean that either you guys are wrong, or the MiG-21 FM programmer and the according programmer at ED have no idea how to do their jobs, correct? :music_whistling:

Edited October 21, 2018 by FSKRipper

[Frederf]

Let's not play that embarrassing game.

[NineLine]

To be fair as well, the product page states it is an AFM flight model, this is a less advanced flight model than ED's PFM, and you may see things not quite as advanced based on that. I don't want to speak for the devs on this, but just my opinion that maybe I wouldn't expect as much as a PFM.

 

And to add to this, there is nothing wrong with an AFM, it can still be a strong flight model.

[-Rudel-]

It's actually an EFM. The webpage wasn't fixed after the new naming convention when PFM, EFM, AFM, SFM, SSM, and ASM were introduced.

[Кош]

Feeling/likeness/comfort is not a conversation about the flight model. Chart comparison is.

[m4ti140]

Feeling/likeness/comfort is not a conversation about the flight model. Chart comparison is.

 

 

Charts don't show you stuff like roll coupling. Nor extreme edge of envelope phenomena.

[Frederf]

Sure charts can show you that, if that's what the chart is showing. We just don't have charts for every conceivable measure. Anyway, language can be objective. Pilot notes aren't subjective; they are not generally numerically precise. That's the only difference.

 

Here is an example statement.

Prestall buffeting in straight-and-level flight at 5000 m begins at an airspeed of 370 to 340 km/h (depending on the weight of the aircraft, its CG position, kind of the external stores carried and the aircraft configuration). This buffeting is slight and its intensity stays practically the same up to the moment of stall. Prestall buffeting does not develop at all when the aircraft flies at altitudes below 5000 m at the above mentioned airspeeds (M < 0.4).

That's an objective statement and can be verified objectively. You can go fly the module right now and almost certainly come away with a confident yes/no correlation.

[Foka1]

I see ZERO constructive comments in this thread.

 

Aluminium Donkey and Auditor, if you have something to show and tell then show and tell, shwow data and present something rather than just claims.

 

Auditor I already saw your report on R-13M missile which I checked and turns out missile behaving very much close to its IRL parameters, that is why I'm skeptic now.

 

If you really want stuff to be fixed stop useless arguing and argue base on data and documents.

 

"From the "digital stall" effect, to the lack of roll inertia" ok, good start you noticed something, then show it on scheme and why you think its wrong according to which source etc. otherwise it is useless thread which has no value for anyone..

 

Present your claims in academic fashion and you will get somewhere, otherwise nothing will happen..

[Кош]

This too. Anyway only numbers should be reported, because with them we can negotiate with the devs.

[BadHabit]

Pumb https://forums.eagle.ru/showthread.php?t=194892

[FSKRipper]

Pumb https://forums.eagle.ru/showthread.php?t=194892

 

Really? The napkin math of the guy which was proven wrong for the M2000, the F-15 and the Su-27 at least. The guy who tried to teach Yoyo FM developing?

 

Nice source...

[BadHabit]

I am not an expert or have a valid opinion on aerodynamics, so I am not here to discus.

I read his napkins and think he has something to say. I pumped a discussion which imho is interesting.

 

He took his napkins and invested some time to solve/investigate a problem. Napkins, drawings and small talk maybe have a solution sometimes hidden.

 

These forums got too serious about charts and numbers which 99% of the users here don't understand or have no reach on them.

[bkthunder]

 

"From the "digital stall" effect, to the lack of roll inertia" ok, good start you noticed something, then show it on scheme and why you think its wrong according to which source etc. otherwise it is useless thread which has no value for anyone..

 

 

Well, it's kinda hard to find data on an aircraft maintaining 2g during a stall... that's because maintaining 2g with a stalled wing is, as far as my common knowledge of aerodynamics goes, impossible.

I really don't think anyone should be explaining this to a developer who is suppsoed to prdouce a flight model, anyway:

 

The wing produces lift > the lift makes tha aircraft fly > the wing loading during normal flight is such that the weight of the aircraft is "supported" by the wing > during a stall the wing has (nearly) no lift, therefore the wing loading is lower than the weight of the plane > the airplane falls.

Ergo, if the lift is not enough to maintain flight (and therefore to produce a force that is at least equal and opposite of 1g in the vertical axis), how can it be enough to produce 2g?

 

 

So, can you explain how is this possible?

Edited October 25, 2018 by bkthunder