Buggy Flight model 2.5

[Robert31178]

Right after I wrote this I was reading some more and found this incredibly accurate quote....

 

"Don’t mistake performance in a specific scenario for overall capability. An F-1 car is incredibly fast, but that doesn’t mean you’ll be able to plow your field with it any faster than you would with a tractor, or even an ox for that matter."

 

Perfect.

[Кош]

Search posts from Sarmatt, Wadim and other confirmed USSR Airforce vets and military flightschool instructors. Its not that bright and shiny... Still, we are not going to have another 21 in this decade though.

[hovring]

Out of curiosity what model fishbed do we have in DCS?

 

 

A quick search, not even took me 10 sec gives me this:

https://www.digitalcombatsimulator.com/en/products/planes/mig21bis/

 

 

Now you actually need to read that yourself to find out what Mig-21 version it is. I will not tell you! ;)

Edited February 13, 2019 by hovring

[hovring]

For a Mig-21 jockey here that actually "like" the Mig-21 FM. (can you like a bird that kills you if you **** up..... well I can ;) )

 

 

 

Can someone explaine this 2G "hard coded" lock I seen people talk about. Whats that and do the Mig-21 IRL have such a look in its flight system?

[HWasp]

Sorry Nealius......Whilst the FM may feel fine to you,the DCS FM is no way characteristic to that of the real MiG-21.

 

 

It's very slow and sluggish to turn,it's clumsy in flight.....these two characteristics are in plain contrast to how apparently the real aircraft performed.Read any flight reports of the MiG-21 and your read it was a real thoroughbred,it turned on a sixpence and unlike our DCS FM......it was a very nimble,and accurate aircraft to fly.

 

 

I have recently been reading the flight reports of USAF F-4 pilots facing the MiG-21 in Vietnam,and their reports only back up to what I had previously read about the MiG-21.All of these F-4 pilots tell of a very fast,lightweight,nimble F1 style of aircraft that could easily out turn them,flying their F-4's.

 

 

Sorry if this makes difficult reading to the DS MiG-21 devs,but your FM doesn't even come close to the real MiG-21.It is not my intention to cause any offence whatsoever,but I cannot accept the FM is a true representation to that of the real thing either.....Sorry.

 

Why is it so damn hard to google “Mig21bis flight manual” (the real one, it’s available in English, second or third search result!!!!) and compare that to what we have now instead of some totally useless subjective quotes like “it should be nimble” and cr.p like that? :doh:

 

If people would do that, maybe we could talk about the real problems like edge of envelope stuff, stall behavior and such...

 

So real problems instead of the bs:

 

1. According to the manual at higher AoA aileron effectiveness should decrease considerably (p.14). I don’t see this modeled, I can roll the plane at high AoA edge of the stall no problem.

 

2. At even higher AoA a rocking from wing to wing developes and increases as AoA increases according to the book (p.15). This is also not modeled.

 

3.The stall itself looks like some weird scripted behavior, especially from the outside.

 

4. There is a very long text in the manual about stability problems with some loadouts at some fuel levels (typically rather heavy air to ground stuff). Never experienced any stability issues due to loadout in DCS.

 

5. Engine just simply flames out at a pre defined speed. This is quite a simplistic approach to enforce the limitations isn’t it?

 

6. Maximum time in second (emergency) reheat is 3 minutes due to turbine strength. I have never had an engine failure due to this limitation, and I always use the second reheat due to obvious performance reasons.

 

7. From the manual p.138: “If the control stick is not set neutral immediately after the onset of the stall (3-4sec) the plane will start oscillating about it’s 3 axes unsteadily with high lateral G forces” It’s not doing that.

 

8. Manual p.141: So called “inertia rotation” May develope when doing continuous rolls with more than 90 degrees per second (that is quite a low value). I have never seen or had such an effect whatever extreme rolls I have performed in DCS. (symptoms: intensive growths in slide slip and lateral G, intensive +or- or alternating G without stab input, increasing roll rate.) This a dangerous departure that actually killed pilots.

 

9. This is subjective: the plane is totally stable with AP stabilization OFF. Never ever used that system other than just for testing it. Did they implement it in the real plane for fun? IRL MiG-21 drivers told me that without the system the plane needed constant corrections.

 

Performance in the normal flight envelope is NOT the problem, it performs as expected or better... Sluggish? Really? Don’t get slow with those tiny delta wings and it will not be “sluggish” lol.

[BadHabit]

Very nice solid points HWasp! This post should be a sticky while all points are not addressed.

[MiG21bisFishbedL]

Citations, too. That's how it's done. I need to hunt down my POH.

 

Out of curiosity what model fishbed do we have in DCS?

 

We have the MiG-21bis (75B) Fishbed-N, the tactical fighter and export version. There are two versions of it, with some avionics differences between the VVS/PVO versions and the export ones. The MiG-21bis Fishbed-L is the export interceptor and features the Lazur GCI system. The one we have, the Fishbed-N, has the SAU and Polyot ILS to reflect a more generalized combat role. They're sometimes designated MiG-21bis-Lazur and MiG-21bis-SAU in nations that purchased them.

Edited February 13, 2019 by MiG21bisFishbedL

[Oubaas]

Can someone explaine this 2G "hard coded" lock I seen people talk about.

 

There isn't one. After reading that repeatedly yesterday, I took the DCS MiG-21 up and pulled +5Gs in a turn without even trying hard. I could have easily overstressed the aircraft if I had wanted to do so.

 

While I have never flown a MiG-21bis in real life, the DCS MiG-21bis performs about like I'd expect it to, considering the design and power. If it's really off, it isn't too far off.

 

HWasp brought up some interesting points that should be looked at, but overall, I think it's probably pretty close to right under normal circumstances. It seems pretty nimble and all to me.

 

You have to fly it the way that it was meant to be flown and have realistic expectations for the aircraft. And it helps if you have a realistic frame of reference for your observations, such as real world flight experience, instead of making observations based on books or other sims.

 

:pilotfly:

[hovring]

So this is not valid anymore?

 

 

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

[Esac_mirmidon]

Is still valid.

 

Look for the latests reports this month.

[Brigg]

Citations, too. That's how it's done. I need to hunt down my POH.

 

 

 

We have the MiG-21bis (75B) Fishbed-N, the tactical fighter and export version. There are two versions of it, with some avionics differences between the VVS/PVO versions and the export ones. The MiG-21bis Fishbed-L is the export interceptor and features the Lazur GCI system. The one we have, the Fishbed-N, has the SAU and Polyot ILS to reflect a more generalized combat role. They're sometimes designated MiG-21bis-Lazur and MiG-21bis-SAU in nations that purchased them.

 

Thanks dude :)

[GumidekCZ]

Any updates to flight model seems very odd to fly now . Bouncy nose and stalls seem it likes no input for stick

 

 

In current DCS Beta I feel floppy flight model with tendency to swing around after every control input. I have set joystick axis curvature, but still at 700kph wobble around like never berfore since released. I dont like it, so Im asking if this was aim of flight model tuning or is it just a bug?

[Nealius]

What are your curve settings? My roll axis is set to a curvature of 20 and I don't have any wobble.

[GumidekCZ]

What are your curve settings? My roll axis is set to a curvature of 20 and I don't have any wobble.

My is set to 15. When in dog fight I noticed that high curvature makes my input in second half of axis range very rough - not good when trying to aim my gunsight (X52 PRO joystick). What I meant is when I fly straight in line, and I make slight input in pitch, I can watch my MiG to wobble 2 or 3 times up and down until finally stable again.

 

 

----------------DISREGARD----------------

I just talked to retired real MiG-21 pilot, small oscilations and little wobbles after stick input was just natural behaviour :) My appologiez

Edited February 15, 2019 by GumidekCZ