Maverick Su-35S

Very good pointing! Yes, think combat configuration..., it still beats the Eagle in turns if both have dogfight missiles left (usually those are the missiles they remain with).

Su-27/33s don't flame out cause of attitude angles, if this is what by mistake you refer to, but below a given G-load, no matter the plane's orientation from the Earth. Nose heavy? Just the opposite. If it would be nose heavy then it couldn't reach high angles of attack, maybe not even reach the critical AoA (less to say the supercritical). Sorry, don't look bad at me, but you have to learn / understand a bit of flight dynamics. The plane's CG (center of gravity) seems realistic where it is, the only problem that comes on when you push the stick until reaching an AoA below -20 is that the elevators become shadowed (turbulent and inefficient airflow) by the wing due to the relative position between the wing and elevators in the plane's vertical plane. The way to get out of the negative deep stall is quite simple, but you need a bit of altitude (at least 2000 meters). Set the controls to direct pitch (needed for high alpha or cobra), fully pull the stick and wait until the AoA goes as much negative as it can get, then release it to neutral once the AoA wants to reduce. If the AoA managed to get below -20, pull the stick and get out of this unstable region. If not, repeat the process..., full stick pull until the AoA reaches a maximum negative value, then release until it drops to below -20. On the other hand, yes, the Flanker won against the Eagle in real tests and beat it in turns. The Eagle had an impossible chance to stay or get behind the Flanker. Now (after latest updates) in DCS we see the opposite, so we need a fix.

I know what you are talking about with the G limitation, but this is not the problem. If people still can't see the difference between the initial PFM and the latest updates, I have to detail things a bit more thorough. 24deg/s at 550km/h with 30% fuel is impressive? Then what do you say about the F-15, did you look at it? Sorry, but you prove to not know how these values are in reality.

Hello, After some update (don't know in which one), changes have been made to both the F-15 and Su-27 in terms of aerodynamic simulation (lift capabilities being easier to spot). Initially (after the PFM came out), both the F-15 and Su-27 were capable of achieving quite authentic turn rates compared to the real planes (of course, depending on IAS and weight). The F-15 only had some critical AoA handicap (initially, now is better) as the plane's lateral-directional control was almost impossible to attain above 20 AoA (30 on the F-15's in cockpit indexer), while the Su-27 was worked quite well from the start in this area. For whatever reason, after later updates (didn't stand to test aerodynamic parameters after each update) the Su-27's wings produce a quite lower lift for a given AoA (lower lift slope) while the F-15 does exactly the opposite. Now, (a bit absurd one will find it), the F-15 turns better than the Flanker at both low (full aft stick full AB) and high speeds (around the best turn corner). For short, with both planes fueled the same (30% fuel), the F-15 completes the fastest (full aft stick from around corner speed) 360 turn in about 14.4 seconds, while the Flanker in no less than 15.8. How did this happen? Here is a track and some output data from it: Su-27 turns badly after latest updates.trk And here's a video of the Su-27's proven turning capabilities: Aerodynamic modelers, can you please tell us what's going on? Kind regards!

Sorry, yeah, it's 2.05, not 2.15 and indeed I forgot the canopy's problem becoming opaque due to temp, yet we were generally discussing the engine's inlet geometry which also affects the Mach limit.

Yes and a reason why the F-16's maximum Mach limit is 2.15, is not because of pressure recovery limitation of the inlet as it is due to a shock reflection down the inlet above that, otherwise it's said that the engine still has enough gathered thrust to push the F-16 beyond 2.2. As someone mentioned about the variable inlet cones on the M2K, yes they work as any other inlet spikes in order to control the normal shock's position down the inlet to give maximum pressure before entering the compressor, but still, I find the M2K's actual acceleration quite exaggerated in DCS atm. Hope RAZBAM will investigate and correct the thrust tables with altitude.

Thanks all you guys for making this think clear known, that the manufacturers can only tell at what thrust force their engine peaked during bench testing and indeed the demonstrated output on an aircraft depends on the geometries that will eventually affect it's thrust, so that 80% is what the engine generally remains with due to airflow problems and not because someone reduces their thrust to 80% on purpose. These are things that few of the majority here know about so it was important;). Cheers!

So again, sorry to bother you with this so much, but until you assure me I kind of feel it hard to believe...! You tell me that the engines on the F-15C (in real life as well as in DCS) develop only 18800lbf (which is 0.8 * 23500) at FULL AB at around sea level at zero IAS (static thrust)? Is this the truth? If not please then, tell us what would that value be in these conditions (static FULL AB at sea level)! Thanks!

Well, it does have a higher T/W ratio when lightly loaded, but all other fighters do the same, so the M2k isn't proving anything magical, in real life I mean, not as it does right now in DCS.

For how long?

You think? The best F-18 pilot would get beaten everytime by the best pilot flying the F-15 or Su-27. The F-18 lacks the T/W that the Su-27 and F-15 have. Although in reality it outturns any fighter we have in DCS at instantaneous turn rate, it's engines won't help it win in sustained turn rates and climb.

Just 80% of 23500 (47000 / 2), which makes 18800lbs? Is that what you try to say? That in DCS, the F-15C has 18800lbf at FULL AB on each engine? At 500kts it's capable to have a T/(W+D) higher than 1? If it's KIAS, then I don't know if the engines (although indeed their thrust increases with dynamic pressure or IAS) would be capable anymore to generate a total thrust higher than the weight + drag in order to accelerate on X-axis at higher than 1G, if this is what you say! The Mirage is light, but it doesn't make any sense to beat the F-15 in horizontal acceleration and climbout (only between some IAS and altitude ranges after latest updates, but still not correct) giving their real T/W ratio. Even by neglecting the drag, the T/W ratio difference is colossal, so it doesn't matter if it's light if by performance isn't that capable. The lift force of the Mirage is also found to be exaggerated. It can't fly in reality as slow as it does now in the sim. Regards!

It was fixed? Read again some more. It still beats the F-15 between some IAS airspeed ranges and at altitudes above 11000meters, besides that it outclimbs the F-15C in every way. Check these threads latest news and get convinced: https://forums.eagle.ru/showthread.php?t=197059 https://forums.eagle.ru/showthread.php?t=199528 The Mirage is still a WIP.

Hello Frederf, I know what you say and by documentation the Mig-21 has 0 wing incidence and yes the AoA shown in outside view is grossly taken as the angle between the undisturbed airflow upstream of the plane and the plane's X-axis. It's not correct giving the definition of the angle of attack, but anyways, the difference between what this wing should have as a maximum AoA and what it would be even if it would be 16 (as you'd suggest with that 1 degree of positive incidence) is unacceptably great. I'll relate this on the bugs forum then;). Kind regards!

At what speed and altitude? If you fly vertically at a low enough TAS (to reduce the drag),let's say 300km/h starting from SL, even 1.1 T/W should get you at least a higher than 1 T/ W+D) and slightly accelerate (TAS increase, not IAS) in the vertical.

The F-15 can't accelerate straight up empty, for example? I read that very useful and interesting document about this guy who flew the F-15, F-16 and MIG-29, yet he says that the T/W ratio was less than 1/1 due to loadout and perhaps he didn't benefit from the 25000lbf engines that the DCS F-15 should have. The real F-15C should be able to prove a T/(W+D), where D is drag force (it matters even at null lift AoA) above 1 even with full fuel empty weight while starting a vertical climb (90 degrees pitch) from sea level if he manages to remain with at least 300-400km/h after reaching 90 pitch. In this condition, the F-15C with 25000lgf engines should normally find an initial TAS (not IAS) increase up to 1.5..2km height before it starts to decelerate (TAS decrease). Under the mentioned conditions, our DCS F-15 has it's TAS drop quite quick instead of slightly increasing. I have the feeling (at least by the numbers) that our DCS F-15C has it's engine thrust lower than it should at low altitude. At high altitudes, it can reach Mach 2.5 so the thrust to drag ratio is relatively correct, even if the drag and thrust may not be correct/realistic, their ratio is as long as it reaches Mach 2.5. For some reason, in DCS, the F-15 has a lower T/W and also T/(W+D) than the Mirage 2000C from RAZBAM and also lower than the Harrier O.o from RAZBAM. Who hasn't inputted the right engine performance data, ED or RAZBAM? If you try a Mirage vs Eagle player vs player battle in DCS, the Mirage outaccelerates the F-15 in the vertical. I've done a test in which I had both planes with 50% fuel, started from 1000MSL and at 700km/h IAS I started a 3G climb until I reached 90 and held 90 pitch until the tailslide took place. The Eagle only reached 8400 meters, while the Mirage passed through 9000m. How come?

Hello, While playing I've noticed something odd regarding the IAS/TAS (while using the outside view IAS/TAS). Every time I reached 22.5 to 22.8 AoA, which seems to be the alpha where the engine surge takes place (you hear bangs from cockpit view), the IAS jumps by adding a couple of knots at every engine surge that occurs. It seems the testers have missed this (couldn't guess this to happen) when they modeled how the engine surges take effect upon the developed engine thrust, because now after every engine surge the engine gives a massive thrust increase for a split second, before it would actually start decreasing. Here's a track providing just what I've said: JAS-37 engine surge thrust increase.trk Besides this unexpected weird engine thrust behavior at surges, this aircraft and "Heatblur" truly deserve their money for a very well and very realistically developed flight model. Hats down!

Again..., I don't even know what to do to convince these guys who made the MIG-21 in DCS that THE SIMULATED CRITICAL ANGLE OF ATTACK IS TOO LOW FOR THIS PLANE'S WINGS! All the facts are gathered around and still they won't review this problem? There are 3 modifications that need to be done inside the aerodynamic input data tables: 1. Reduce the CL0 - the AoA 0 lift coefficient. It is too high and for this reason this aircraft would be flying supersonic (through shockwaves) at a negative AoA at 1G, which is only possible if this plane has a highly cambered airfoil section, which is not true! The MIG-21 has an almost symmetrical wing airfoil from root to tip (Tsagi S12 has a very low camber), therefore, the CL0 must be very low (quite close to zero). Some data on the internet says it is in fact purely symmetrical, but actual airfoil coordinates show that it is very lightly cambered. Still, the CL0 value must be very low as compared to what it is right now. 2. Increase the critical AoA from 15 to 20..20.5, which corresponds to this wing, NOT airfoil, but whole wing. 3. Reduce the lift versus AoA slope according such that the maximum CL (or lift coefficient) would not be altered after correcting the critical AoA. 3 steps and everyone's happy again. What makes it so hard? You don't trust what I'm saying, right? You need "proof" as always. OK! But one thing's for sure: Even if we don't have access to real wind tunnel data, we should at least agree to the following logic: If the A-10's higher AR wing, zero wing sweep, very high camber as compared to MIG-21's wing, has a critical AoA of 16, the MIG-15, a higher AR, relative sweep, non delta, has a critical AoA of 18, the Su-25, higher AR, very low sweep, has a critical AoA of around 17, how come someone forced a critical AoA on the MIG-21's wing to just 15? Keep in mind that between 2 wings with the same AR and sweep for example, one being a delta and the other a non-delta, the delta wing will always have a higher critical alpha if the airfoils don't differ too drastically (ie: if one is being symmetrical and the other highly cambered)! Just by these contradictions one should understand that even if the true critical AoA isn't exactly known, it should definitely be higher than those of the mentioned aircraft. This is common sense for anyone with a good knowledge and experience in aerodynamics.

Please let me know how would you find these differences affecting what I'm trying to say. Let's openly discuss about it:thumbup:! Sorry to contradict you here, but this can only be physically possible (for a Su-27, F-15,etc.) at an AoA quite low or at a G-load far below 1 while holding full aileron and rudder just to neutralize the rolling tendency, so all the flight becomes nothing but a long plunge towards earth. Don't listen too easily on what's being said of that Israeli F-15 flying back home with a whole wing gone. If this was true, then it can only be physically possible if the lift produced by the wings is far below the one produced by the fuselage, which is absurd. Most definitely that wing was only about half gone, not completely gone as people lie about just to make it look like a wonderful story or to make the F-15 look like some magical craft defying physics. I trust only physics and validated numbers as they won't lie to me, not fructified stories from Youtube. Because the MIG-21's wings lift is so precious might drive you to believe that the ailerons have a huge impact on the lift differential on the wings, when in fact they don't. Maybe on drag, yes, they have a huge impact generating the known yawing moment due to roll inputs which looks correctly simulated, but not on lift. If the aileron would have an effect on the wing at stall AoA that would would take place only on the aileron's region, not affecting the whole wing, but only a small area (less than a quarter of the aileron's span/lenght) slightly inboard of the ailerons. These are facts, not aberrations. Not what you're saying is aberration, but what's being simulated at this moment. Extremely high roll rate? Compared to DCS MIG-21, it's twice as worse under same conditions of AoA and IAS, not to mention how badly the Mirage's roll rate decays when approaching critical AoA and keep in mind the huge difference between the Mirage's aileron area to total area ratio and comparable deflection and the aileron area to total area of the MIG-21 and both aircraft comparable rolling moment arm (arm between the aileron's center of pressure and plane's rolling axis), plus the fact that the Mirage has a some sort of ARI (aileron-rudder interconnection) system which deflects the rudder towards aileron input. All these factors combined affect the resultant roll rate. It should be clear that there's something still in need of work on the MIG-21 and not on the Mirage-2000C which behaves remarkably accurate. The JAS-37 also flies remarkably realistic and does not develop the strange aerodynamic forces present on the MIG-21. So far, the 21's aerodynamics still look like a WIP. Initially, when the MIG-21 came in DCS, it was far more realistically behaving than it does now. Some aspects have been fixed, but a lot more got worse somehow. If tweaks made it worse, then tweaks can also save it and make it better. Correct, but it's much more important which areas get wetted (as our discussion seems to lead to) by these vortexes and their intensity for a particular AoA or somewhat to say, the intensity of the vortex versus AoA slope, which drastically affect the vortex breakdown AoA, known as supercritical AoA. If such a powerful vortex can "wash" the wing as far outboard as where the ailerons are, then the ailerons effectiveness decay would be delayed and take place at a higher AoA, closer (yet below) to the vortex breakdown AoA. After passing the supercritical AoA, any aileron movement should find almost (yet not null) no roll response or as life tests show, the ailerons lift vs deflection slope becomes about 10..15% of what it was below stall. But there is NO such thing as high energy vortex developed on a MIG-21's wing and furthermore not possible for the tiny vortices developed along the wing's leading edge that cannot wash out the nasty boundary layer separations and flow reversals that take place very close to the ailerons. Here, this might be very useful and you may find out that there isn't a very big difference between the general wing shape (delta or swept wing) on how it affects the general airflow and flow separation / flow reversal patterns. When a wing becomes more swept, these effects will be less and less different for different wing types. The flow separation effects that take place closer to the wingtips are more affected by wing sweep angle rather than planform shape: "The videos are a valuable tool of information" If they were to be more effective due to vortexes (which you presume might reach the ailerons and beyond) then how come we don't see at least the same amount of aileron effectiveness at AoAs above 20 (look how low it is...) on aircraft such as Su-27 which has a far more effective vortex spreading across it's wing as compared to the MIG-21's wing. It's all about the contradictions that emerge from this. Even the Mirage-2000's wing (which you thought to be rather comparable) with slats (which drastically improve the airflow on the ailerons) still has a roll response very comparable to that of an F-15 (slatless wing as the MIG-21) of Su-27. Same goes with the JAS-37. Do you want to say that somehow, irrationally, the MIG-21's ailerons are washed by a tremendously well stabilized and firmly attached vortex which keeps the aileron's lift versus deflection unaffected by alpha? There's definitely something out of the ordinary going on right now and because this didn't happen in previous patches, it's certain that this can be fixed. Kind regards, Mav.

Hello, The moments of inertia about the 3 axis with their respective radii of gyration have been personally calculated after splitting the plane into the major components that take part in the plane's general weight by knowing their 3D positions and mass. I could not find the real value anywhere and this determined me to try and estimate them. I cannot guarantee how highly accurate these determined values are, but giving the fact that I've used the same model to determine those of an F-16C, for which I had comparison data and the mean error was around 2% (98% accurate), I am confident that in this case they cannot be lower than 94-95% of the real values. About the ailerons, yes, as far as I know they are being driven by some clutch systems which are designed to maintain a relatively constant aerodynamic load on the ailerons. Because the aerodynamic loads vary with the square of the equivalent airspeed, the ailerons deflections will increase with a square function of decreasing airspeed or the deflections will decrease with a square root function of increasing airspeed. Yet I still believe the roll rate to be too high at low speeds between 100 to 400km/h. As compared to an F-15 in DCS, the DCS MIG-21's roll rate at 200km/h with it's small ailerons is 43% higher. It takes 2.1 seconds for the MIG-21 to complete a 360 roll at constant roll rate at 200km/h, while for the F-15 which has elevons (that should further enhance the roll rate) it takes 3.7 seconds to complete a 360 roll at constant roll rate at 200km/h, which seems exaggerated for the MIG-21 to roll so fast. Only by putting into balance or comparing the ratio of aileron area to wing area of the MIG-21 to that of a Su-27 (I took the extreme examples as a better proof) combined with the ratio between the MIG-21's full ailerons deflection and the Su-27's flaperons + elevons deflections, one can notice that something doesn't add up for making the MIG-21 reach such roll rates. Although the ratio between the aerodynamic rolling moment of the MIG-21 and it's rolling moment of inertia may give a rolling acceleration higher than that of an F-15 and Su-27, this ratio (roll angular acceleration) still seems quite too high. Even when flying at 80km/h (using a ballistic trajectory) and jerking the stick full from side to side, the rolling response looks obviously short, the plane would act as if it's very light. As far as I remember, I had given a link of a real MIG-21 which performed a 360 roll after takeoff at around 450-500km/h. That video could've been used as an inverse engineering to determine the rolling moment of inertia and roll rate with quite good accuracy. If we don't have any other reliable data, the videos, if used with precise measurements can give very accurate true data, but of course, this depends on whether we want to make it better or not. Here is the track regarding the MIG-21's roll rate vs airspeed and rolling inertia: Roll rate and rolling inertia problems.trk About the highly swept deltas (the mig-21 has 49 degrees at the 25% chord spanwise line), I am very sure that the flow separations close to the ailerons gradually reduce the ailerons lift vs deflection slope as the wing's AoA gets closer and closer to critical and render them completely useless (lift vs deflection becomes almost null) by the time the wing reaches critical alpha. Tip stalls which usually engulf the ailerons as well, occur a lot more prematurely with higher sweep angles. For the MIG-21, the ailerons stall/ineffectiveness is a true fact. This is the main reason why the pilots are told to use rudder instead of ailerons for controlling the roll as they approach the critical alpha. Not only that the ailerons lift effectiveness should decay with increasing alpha (both positive and negative) and become null once the whole wing is stalled, producing differential drag only, but as it is right now, the ailerons produce about the same differential lift between the wings when fully deflected at angles of attack as high as 50 as they would at produce at low AoA (0..10 degrees), which is abnormal to say the least. Here is the track to review the abnormal aileron lift effects at angles of attack more than double that of stall: High AoA ailerons response is same as for low AoA.trk (Now, I wish you luck with the tracks, because they don't seem to follow exactly what I did so the plane may crash randomly at each retry to replay, although I didn't crash and showed everything that's not alright) Again, take into comparison the DCS F-15's roll response when the wing as at or near critical AoA. What do you get? The wing (which is a delta with an even lower sweep than that of the MIG-21) is still capable of slightly increasing the lift coefficient between 20 (30 on the indexer) to 25 AoA (35 on the indexer) while the ailerons effectiveness has already become very low by the time 20 AoA was reached. The same goes for the Su-27. You can't say that ED had simulated them wrong or copy pasted one's values to another. By tests, they match each real individual plane remarkably. Another discussion which has the highest priority of all is that of the true critical AoA of the MIG-21, which is in no case 15 degrees. Even high sweep and relatively high aspect ratio wings (for fighters) like those of the F-86, MIG-15, etc. have a critical AoA of +18 AoA. The delta which always has offered a benefit in critical AoA increment should in fact give the MIG-21 around 20-21 degrees critical AoA. Another discussion would be that of the MIG-21's wing lift at zero AoA and also lift slope (CL vs AoA). I am personally involved in enhancing/correcting the flight behavior of various aircraft in another simulator (not giving name) and I feel an urge to see owned aircraft in DCS respect real data, and if real data is not found/available, use all the engineering methods that you have to determine the data or at least get closer and closer to it by whatever means..., of course, if our goal is to have that aircraft behave as close as possible to the real thing. My wish is that at least one after another, as the time permits, all these aspects will be revisioned. Kind regards!

Hello, After doing a research on some flight dynamics constants of the MIG-21, this is what resulted: For a given weight of 8700kgf, which corresponds to a clean loadout, full fuel + the pilot, the moments of inertia should be as follows: Ixx (rolling moment of inertia) = 6147 kg*m^2 or 145880 lb*ft^2 Iyy (pitching moment of inertia) = 67510 kg*m^2 or 1602052 lb*ft^2 Izz (yawing moment of inertia) = 77091 kg*m^2 or 1829398 lb*ft^2 The following are the corresponding gyration radii of inertia: Rolling radii of gyration: 0.8406m or 2.758ft Pitching radii of gyration: 2.786m or 9.14ft Yawing radii of gyration: 2.977m or 9.767ft If one may introduce these constants in the flight model file of the MIG-21Bis in DCS will finally have this bird responding authentically. Right now, the pitch and yaw moments of inertia seem appropriate (by how the plane responds to sharp full elevator and/or rudder deflections), but the rolling moment of inertia is still quite lower than expected. You can make the plane roll left and right so quickly at 200km/h as if it were at 300km/h...! Another thing is that the ailerons are as efficient way above stall AoA as they are for low AoA, which is abnormal. Above stall AoA, the ailerons efficiency should become greatly degraded if not null, especially if the leading edge has no droops/slats to enhance the flow. My only goal is to enhance or to help enhance the flight behavior of aircraft in DCS. Best wishes, good day!

Thanks for letting us know about the Chap and appreciate your replies!;)

It seems that after the last updates, the IR missiles got even better. It became more difficult to make the IR seeker (of Chaparral and Avenger) break it's lock with the initially required number of flares (before the last updates) and high-G maneuvers. Now you need to puff a lot more flares giving the same conditions of distance between IR missile and target, target's heading, alt and speed. Judging by the simulation, I understand that these missiles (of Chap and Avenger) can still be deluded with flares, so they're not in the category of image processing target recognition? Or even the imaging seekers can still be deluded with flares (if the Chap and Avenger have such advanced missile seekers)? If the FIM-92 and MIM-72 seekers are still older ones (not IR imaging seekers), why have they been made more resistant to flares now? Wikipedia's (quickest info helper) description on FIM-92 and MIM-72 can be useful for enhancing the performance levels of our missiles in DCS. For instance the MIM-72 seems to be much easier to trick with flares, requires more time to lock and is generally worse than Stinger (FIM-92). Although it says that the F and G(used in DCS) models have been improved, i'm not sure about how greatly was their performance increased over the A/B/C versions. In DCS, the performance between MIM-72 and FIM-92 seems almost the same, expect for max range, max. speed and possibly G-loads. Thanks you for your time and patience!

Speaking of witch, I've read somewhere about the F-5E's in flight performance and was amazed to notice that although it's wings start stalling above 25 true AoA when droops are fully deployed, the flow that remains attached to the wing surface along the path of the strong vortexes created by the LERX (leading edge root extension) only separates above +70 AoA where the vortexes break up (supercritical AoA). Although the F-5's wings have a higher wing aspect and lower wing sweep than those of a MIG-21, which mandatorily reduces the critical AoA, the early F-5's wings which were fitted directly to the fuselage without any LERX or apexes were stalling above 18..19 AoA when the droops and flaps were fully retracted. The droops usually increase the AoA with around 4..7 AoA depending on their design. Slats (fowler leading edge devices) however can increase the AoA with as much as 8..12 AoA (737s slats do so). So even like that (without droops and flaps) the F-5's wings had higher AoA than what those on the MIG-21 right now. The Su-25s indeed start to encounter aerodynamic buffet when the AoA indexer reaches critical and the true AoA is around 15, but the lift to AoA slope is still positive (although curved) between 15 and 18 AoA. Only above 18 AoA the wings of the Su-25s physically start to develop stall (flow separation). The Su-25s, A-10s and L-39s with their straight and high aspect ratio wings still have a critical AoA above 17..18 AoA, so it makes no sense for the 21's wings to stall even earlier than that. The maximum thickness and camber of airfoils indeed affect the critical AoA (higher thickness and camber give higher critical AoA), but only by 2..4 degrees of AoA (so not that much) between a very thin and straight and very thick and cambered one. The strong impact on critical AoA is controlled by wing aspect ratio and sweep. Although both the airfoil shapes and wing aspect ratio and sweep (combined) govern the maximum achievable critical AoA, the airfoils used only affect about 25..30% while the aspect ratio and sweep affect 70..75% of it. So, once more, through every example the MIG-21's wings should provide a much higher AoA before the flow separates. I'm not making this up nor wanting to waste my time, but what I'm saying is based on years of research/experience and can be found on the internet (if one has the proper patience and knows what to search) and technical reports and LN or other 3rd party members can start researching to make sure that people are right and not trolling or trying to create confusion. Here's an interesting article regarding the MIG-21's in flight performance: http://www.military-quotes.com/forum/fighter-performance-actual-plane-analysis-t86206.html Exactly what I'm saying about the critical AoA is also stated here. Just scroll down to about half of the discussion and you'll find this: "Aircraft’s stall speed (speed at which dynamic directional stability breakdown occurs) is function of Mach number, because directional and lateral static stability usually decreases with speed. Stall angle of attack decreases from above 30º (far beyond indicated α) at Mach 0.2 to 20º (i.e. 33 units local angle of attack on indicator) at Mach 0.95. In those days when MiG-21 was designed, electronic flight controls to limit the angle of attack in function of Mach number didn’t exist. A fighter was built primarily for high speeds, high altitude interceptions. At slower speeds previous generations MiG-19/17 were better. Designers put the angle of attack indicator, calibrated in local angle of attack, to warn the pilot of approaching stall limit. At recommended and allowed limit 28 units (about 17º true angle of attack) safety margin to stall is from 13º at Mach 0.2 to 3º at Mach 0.95." "Just before stall α, aircraft nose would start wandering accompanied by more noticeable wing rocking (roll oscillations that intensify thru the stall), symptoms of dynamic directional instability. Stalling proceeds more vigorously with fewer signs at higher subsonic speeds." The statements tell important (and nice) effects that need to be considered for more accurate/correct simulation. The fact that near stall AoA (18.20) the MIG-21 should experience reduced lateral (roll) and directional (yaw) stability which allows the wings to start rocking more and more as the AoA passes stall (above 20). The rocking effects will normally dissipate a couple of more degrees of AoA above stall (some 2..3 more) while the lift would still remain high (perhaps with slight drops). If not asking too much, we're expecting to see this simulated as well (if possible) in the future updates. Regards.

Good job Leatherneck! Great work and progress on the 21! After the last patches it seems that the relation between aerodynamic moments and inertial moments has passed through step by step enhancements. Now the pitch and yaw aerodynamic moments to inertial moments ratio seems pretty authentic. Even without maths to prove it, the pitch and yaw stability derivatives and aero moments look very right. The maximum roll rate and aerodynamic rolling moments to inertial rolling moments are also realistic/authentic now, but, there's still some last work to be done: the variation of aerodynamic rolling moments with AoA. So far, no matter the AoA, the aerodynamic rolling moments seem to have the same value from null lift AoA to critical AoA, which still isn't right. The rolling moments and roll rates should drop exponentially from the highest value (found near zero lift AoA) to the lowest value at stall AoA. Above stall, the rolling moments should be very low and become zero once the beta (sideslip) angle reaches a certain amount combined with the AoA. Even so with these aspects still requiring attention, we saw efforts and great implication from the guys at LN regarding the authenticity of the MIG-21s FM, we're almost certain they'll carry this one out as well. In the near future, the MIG-21's critical angle of attack will also be brought back to +20 (as it was when MIG-21 first appeared in DCS), lower and correct lift to AoA slope and lower/correct maximum lift coefficient. That's all we ask for;). Again, with honest respect and gratitude, good job LN for not letting this baby down! Waiting for the rest! Best wishes!