Maverick Su-35S

Regarding the inverted flat spin, it's simply exaggerated. When I'll get the time I'll put my view (as an aerodynamicist and flight dynamics man) into perspective. Indeed due to the relative position between the elevators and wings (in vertical plane), the elevators become shadowed by the wing at AoA's below -20, -25.., but the effect of lift loss on the elevators due to wing shadowing should be much lower than it is right now simulated and this is mainly due to the fact that the LERX still generate enough high energy vortex under the wing now (at negative AoA) which is more than enough to keep a good airflow reaching the elevators, so the unstable pitch down moment should be much more reduced than it is. When Flanker pilots develop the tailslide at airshows their nose doesn't even drop below 80.85 degrees of pitch down attitude, while in DCS you enter negative deep stall rapidly, so this thing can be easily spotted as abnormal. If real pilots would perform the tailslide they should all die as DCS suggests, lol! Again, this is another discussion for which an important separate thread should be started The blackout simulation in DCS is probably still a WIP right now. I have talked about this myself for years and it seems people like to play deaf about it. Real pilots (not starving monkeys) can stand at 12G for as long as 15 seconds minimum or at 9G for 30 seconds with no light loss (no tunnel vision yet), while in DCS your pilot blacks out at 9G in 5 seconds (chronometered from G onset). Incredible isn't it? And about the redout in DCS, it's even worse. Only of you do a fast roll you enter redout=))). Fu#@ing hilarious, but I don't know if they're going to fix this if people are not pressing them to change their view on blackout. Regards!

The Flanker's lift slope and supercritical AoA (where the highest post stall CL is obtained) should be very similar to that of an F-16, and here's the F-16's real aerodynamic performance data: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800005879.pdf As you can determine from the tables (page 60 of pdf), the F-16 has a CZ of 1.65 at 25 AoA at zero elevator deflection and no flaps, at Mach 0.05. As Mach increases towards around 0.3, all known airplanes find an increase in lift slope and maximum CL. I remember (years behind) from some tables versus Mach, that at Mach 0.3, the F-16's max CL rises to around 1.78 (from 1.6 at very low Mach). Only above Mach 0.3, the critical AoA and maximum CL start to decrease. The peak critical/supercritical AoA and CL max are usually found around Mach 0.3. In DCS, at Mach 0.3, the Su-27 has 1.9 with full flaps at 25 AoA. The flaps always increase the local CL, so as a comparison to he F-16's data (with no flaps), the Flanker's CL at 25 AoA with full flaps should be higher than 1.78, I'd say roughly around over 2. 1.9 as it is right now doesn't seem too low, yet for some reason during actual simulation in DCS even the Eagle out turns the Su-27 at any speed regime at similar G-load and AoA and the Flanker isn't proving real life comparable turn rates. The turn radius is inversely proportional to the turning capability of an aircraft (CL times wing area divided by weight force). Right now the Flanker not only has a very poor constant turn rate, but also the instantaneous turn rate is lower than that of the F-15C and the turn radius is almost identical to that of the F-15 now when it should be quite lower. This stuff doesn't look normal. The Flanker (clean loadout and around 25-30% fuel) should be able to complete a 360 horizontal turn in merely 12 seconds starting from corner velocity (a bit above 700km/h IAS), not 16 seconds. Reality speaks, no me...! In real life, as provided in those videos, the averge turn rate of the Su-27 is around 30 deg/second (360 degrees in 12 seconds). That is average, not maximum which may be 50% higher at corner velocity and 9G. Regards!

Yes, that's what I'm saying. The turn performance of the Flanker is very degraded (became unrealistic) from earlier updates. What makes you think I've said the other way around? I know it doesn't affect G-load, but only AoA. The AoA is not limited to 26, but to 22 at the moment. With that override you can hold around 30 (but varies with trim). I don't know what am I doing wrong cause it seems that you understood me the other way! Regards!

Made me curious, are the changes in a temporary wrong direction? Nothing new! What's important are the long term corrections! Regards!

One might want to take a look at this as I'm bothered talking in the name of truth! At page 28 you can read the following: "Alleged results of so called simulated combat between Su-27 and F-15 during the Su-27’s visit to U.S. were not serious because the Sukhoi even without afterburner, not exceeding 18 º α, succeeded to outmaneuver F-15." Sometimes, the word "alleged" is used on purpose by some who don't accept the truth. Regards!

Because that is usually the maximum amount of fuel the airshow planes remain with when starting this manoeuver. I might be wrong about the exact amount left when they do this, so ask a real airshow fighter pilot for this info if you have the possibility. And because of this quantity as a benchmark for having the Flanker being able to do a 360 in 12 seconds (no other fighter can do this), I also used it in the sim (game at the moment) for a better comparison. Regards!

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.

OK. Thank you! So that .lua file is for the AI and not for a player flown aircraft. Then if that lift coefficient of 1.28 (which seems to be maximum in the tables) is for AI, I wonder what's the value simulated for the player's aircraft and why would it differ? Meanwhile I've moved to the thread you suggested me for more elaborate discussions about the Mirage's flight model. Regards!

You can't elaborate why but you do happen to disagree..., ok! Sooner or later the truth about those apparently "magical" stakes will come out. If they were for lift enhancement they have been place in the wrong spot at the wrong size. I've done a short calculation based on theory and some real data on a wing similar to that of the Mirage which clarifies that the simulated lift on the DCS Mirage's wings is beyond normal (much higher). It will be discussed on the following thread: https://forums.eagle.ru/showthread.php?t=197059&page=7 Regards!

We'll do! Regards!

I might apologize for using that word, but it's the way these "people" comment about the Mirage (as it's some sort of a miracle for them) during play for how quickly the plane turns and climbs and does everything else against all other fighters in DCS and don't understand that this aircraft's simulated performances need more attention. They like it a lot, of course they do, cause they beat both the Flanker and F-15 in turns and climbs, so, how could they be "disappointed" of the new product? Some of them have spotted that something's odd about how this plane performs against all other, some don't want to pay much attention which degrades the ability to spot the things that don't add up. They must test a little bit more, cause I have done just a few tests (not to comprehensive) and it seems that my allegations are facts. Check the latest message. I agree, I didn't even believe there would be a difference in aerodynamic and engine thrust values if both the AI and player aircraft would fly with the same level of realism. This is strange and I hope this won't remain the same forever, but of course, this is ED's problem not a third party's problem. I totally agree, so let's be constructive and make more tests and gather more real data!;) Cheers and kind regards!

You did from FL350 and Mach 0.9 only? Why didn't you try testing from higher altitudes and different speeds also? Try testing from above 11000m or FL360+ and see what happens. Try accelerating in level flight from 400km/h IAS to 700km/h IAS or from any lower Mach ranges and see the difference! Also, test both planes (Mirage and F-15) starting from whatever fuel quantity (but both the same percentage) in vertical climb at FULL AB and from various altitudes and climbout G-loads (between 2 and 4). You will surprisingly find out that the Mirage climbs higher than the F-15 every time. Depending on initial conditions (initial altitude and TAS) the maximum difference of altitudes reached may range between 0.5km to 3km. From what can be rapidly concluded is that the Mirage's engine doesn't loose maximum thrust with increasing altitude as any other fighter in the sim does, even the MIG-29 which has pure turbojets (very low bypass engines) loses thrust with altitude faster. Is it really that way? Again, it's either the Mirage's engine modeled better than anything else in DCS and ED has a problem on all their FC3 planes (not impossible), we shall investigate that if what we are doing here is in the name of realism or the Mirage's engine thrust tables need a revision if the engine's thrust doesn't decay with altitude as fast as in reality. This is what results as X axis acceleration at any altitude higher than FL360: Some people's attitude looks just like a "sneak around the corners" quite often, not to accept what's true the first time! If the overall thrust (neglecting those abrupt variations with speed and altitude) might rather be a problem with ED's FC3 fighter planes engine performance instead of Mirage's engine performance which seems correct in terms of T/W ratio compared the the real Mirage, the aerodynamic polars (lift vs drag vs AoA) really are a problem. The drag to AoA's function exponent is too high, reason why the plane falls on it's belly (90 AoA) at around 125km/h IAS (this tells the drag coefficient is of a wooping 2.7 at alpha 90) instead of at least 190km/h (which corresponds to a realistic CD of 1.15 at 90 AoA) as EVERY plane does in reality. The resultant lift force is also exaggerated! No Mirage 2000C flies at critical AoA (30) at just 94KIAS while weighing 9300kgf (20500lbf) as it happens in the sim right now. I have read somewhere about a demo flight in 1978 where a Mirage 2000C prototype (much lighter than today's combat fighter) managed to fly at a minimum speed of 100KIAS and lower weight than 20500lbf (perhaps maximum 19000lbf), thus the CL was way lower than it is in DCS. I'm not trying to make things up, it wouldn't be my in advantage after all, but I just want to look at things from a more realistic point of view. About those strakes near the inlets which people think can produce tremendous lift, from my experience as an aerodynamicist they can't produce more than a couple of percents more lift or higher critical AoA (5%, mostly 10% more, idk), firstly due to their position relative to the wing, secondly due to their size. I don't know their exact reason for implementation yet, but it might be to enhance the directional stability (better/cleaner airflow wash on the vertical stab) as I know other planes have needed before, but I strongly disagree that above the crude wing's maximum lift capability with slats out, these elements would increase the lift as dramatic as I see it in the sim. Regards!

OK. Thank you! So that .lua file is for the AI and not for a player flown aircraft. Then if that lift coefficient of 1.28 (which seems to be maximum in the tables) is for AI, I wonder what's the value simulated for the player's aircraft and why would it differ if this is a realistic simulator O.o? Regards!