Maverick Su-35S

Thanks you, but i've already mentioned the same in my earlier posts, when, although i've referred only to the critical or stall AoA, it was logic that the AoA travels with airspeed for the same 1G flight and you can build a diagram for real values (reading the pitch attitude indicator) and those shown on the AoA indicator.

Good question, but probably only the devs who worked on the aerodynamic model could tell. It is possible to also extract the drag force for any given AoA as long as you know the glide ratio (that can be determined experimentally in the sim) and the G load (from where you extract the lift force, knowing the weight of the plane also) at that AoA, but this requires some passion to do! A very general formula (usually gives underestimated total drag values because it doesn't take friction, form and parasite drag into account) which tells the drag coefficient at a given lift coefficient (at a given AoA of course), which is also known as induced drag, is this one noted with CDi: http://www.grc.nasa.gov/WWW/k-12/VirtualAero/BottleRocket/airplane/Images/induced.gif

Thanks you "FishBike", so the indicated AoA onboard the aircraft is not the real angle of attack between the wing's chord and the freestream air. The conclusion is that the real angle of attack after which the plane stalls is 20.

Sorry I didn't understand the idea of "local AoA", just confused it with the real one. Thanks!

Wait a minute, are you sure that the AoA indicator on the right upper right corner of the front cockpit panel indicates the angle in degrees? Then there's a problem somewhere because the MIG-21 in game stalls at exactly 20 REAL AoA not 33, which is also what the pdf that i've provided tells. You must keep in mind that the angle that the vane measures is almost always higher than the angle at which the undisturbed air meets the wing's airfoil chord IF the vane is mounted sideways and close to the fuselage, as in this picture: Now i don't know whether the 21 measures the alpha (AoA) and beta (yaw/sideslip) angles from that nose spike (which indeed should measure the correct and real AoA/Beta) or only the alpha from a side mounted pivoting vane (which will always show you an exaggerated angle due to the airflow that wants to go to the lower pressure of the fuselage) If you want to see at what angle of attack any airplane stalls, do this simple test: Fly your aircraft straight and leveled trying to maintain 1G all the time (so, always try to hold the vertical speed indicator near 0) and watch your pitch attitude indicator which doesn't lie..., and as you gradually reduce your airspeed and carefully holding 1G you can see at what pitch angle your plane starts to stall, and that's your REAL angle of attack for stall not the indication on the AoA which might be wrong! For short, when you fly straight (your real path is aligned with the horizontal) and with no roll angle, your pitch attitude indicator is also your real angle of attack indicator. I'm waiting for you answer. Good day!

Well, as far as it's usually found in areas regarding the real angle of attack in relation to the indicated angle onboard the aircraft, the latter is said to be measured in units, not degrees, so it's a common definition for AoA indicators. I've also read the topic for the F-15, and as GGTharos said there, that indexer for the Eagle is always showing you 10 degrees more than the real angle of attack. I don't know whether it's the same story for the MIG-21 as well or different, but this we must find out. I've also shared a document about it in the first post. Read it (it's quite useful and interesting) and you'll see the relation between degrees of angle of attack and units indicated (for the AoA indicator). So regardless to the Eagle where you only substract 10 from the HUD's AoA indexer to get the REAL angle of attack, for the MIG-21 this might not be the case because for each plus unit on the AoA indicator, the real AoA in degrees will increase less and less (example: for 10 units you have 4 deg. of AoA, but for 20 units you'll have like 6~7 degrees) so it's not varying constantly.

Hello. Is the AoA indexer showing the real angle of attack of the MIG-21, or it's just measured in unit? If these are units of AoA, do they linearly vary with real angle of attack, or non-linearly? From what I could find in this unique post about the real 21's high alpha capabilities ([ATTACH]105667[/ATTACH]), these units don't seem to be linear (meaning that it would be hard to express a general or constant relation between the indicated units and the actual/real angle of attack of the plane). If the real mig-21 completely stalls the wings (generated wing sweep angle vortexes also break up and detach) above ~20 deg. real AoA, which would be ~33 units on the AoA indexer if they are units indeed, you have achieved a great and detailed flight model simulation that very few might actually have learned about. Great work! Making the best out of MIG-21.pdf

Good. At least someone told about what I was planning to ask. So the AoA indexer on the HUD will always show you 10 degrees more than real and it usually kicks in above 18 (8 real AoA).

This is a good document showing how was the F-15C/A's CG travel being calculated and evaluated and it could be a good reference for the F-15C's flight model devs in DCS. Nevertheless there is another document which might be useful as it investigates the real aircraft's responses at certain AoA and flight regimes with commanded and uncommanded aerodynamic loads (flight control inputs). F-15 Stability and Flight Characteristics.pdf At some points in the document (at pages 11-20), the aerodynamic asymmetry due to the gun's venting system and loadout asymmetry (aim-9's for instance) is evaluated and can give a clue of how the real F-15 might encounter a right rolling moment (where the gun is placed) in clean configuration or with loadout when a certain REAL and HUD indexed AoA is achieved and only aft stick is implied. Might be interesting. The document also refers to wing rocking effect (rolling oscillations) when the aircraft is pulled above an AoA region with no lateral stick applied. -this can be very well seen on the MIG-21 module above stall AoA-

Thank you Sobek! I just didn't know if the F-15's flight model is still under development. Hopefully this is the answer why the yawing of the aircraft at negative lift doesn't give a correct response in the end (although it initially tends to be right). I don't want to be off topic, but I just couldn't stand not to test the MIG-21 last night after it came up and i'm totally excited on what they've achieved for it's flight model (except for some behavior above wing stall angles). Yet the 21 reacts correctly when yaw is applied at negative lift/AoA, making the aircraft roll opposite to the yaw continuously as it should.

Sry, I didn't understand the meaning of proportional in the first place! Judging by the fact that even the F-86F has a full control of the airbrake's deflection using airbrake in/out switches, so does the A-10 and F-16, why can not the F-15C have? But i guess the devs or someone with more knowledge about it could give the answer!

If you don't have an axis available for the air brake at the Axis section of the controls, it only acts as an on-off actuation so far.

Hello again! I'd like to address a few questions to somebody here or from anywhere who has enough good knowledge in aerodynamics and/or flight dynamics, because I really don't want to waste time. I know that there's no simulations on a PC that could have reached a 100% accuracy level so far and I'm not asking for that! But I believe that I have the right to ask some questions regarding the F-15C's PFM as long as the DCS's site claims it to be an authentic recreation of the real F-15C's flight behavior, as the statement tells: "Professional Flight Model (PFM), developed in cooperation with F-15 pilots" If there is any F-15C test pilot, active or ex pilot who can help to answer the 2 following questions, I would greatly appreciate. The subject of this post is mostly concentrated on the 2nd question, which is more important: 1. What is the highest negative AoA that the F-15C's flight control system allow for the real aircraft? I know that at negative AoA the wings won't benefit of the higher energy vortexes created between the engine inlets and the canopy which help increase both the fuselage's and a good portion of the wing's lift, lateral-directional stability and critical AoA (that apply when flying at positive AoA), because they won't generate at negative angles, so there is a huge constraint in negative alpha due to these factors, but how far this restriction reaches? You do know what a roll due to yaw is, as well as an adverse yaw due to roll (the yaw due to roll is not the subject) when we are at positive alpha (AoA)! For instance, and especially on high sweep wings (like the F-15) with 0 dihedral between the wings, when you have 1G at a constant given AoA and you yaw the aircraft only by rudder input, the leading wing will have a greater lift gradient (what we usually call the lift vs alpha slope) than the lagging wing, which creates a lift asymmetry between both wings, thus the leading wing "rolls around" the lagging one in the same direction of the yaw, but what should normally happen (how would the airplane react) when you have negative alpha (AoA) giving the same conditions, of course at -1G the least? That's right..., you should get an opposite roll due to yaw and vice-versa for yaw due to roll (the plane will yaw in the same direction as the roll). So, for stick forward conditions (where the alpha is enough negative to have the wings produce negative lift) every reaction in yaw and roll is reversed when the corresponding input is solely applied. 2. The second question is: Why does the F-15C in the sim tend to react correctly in the first moment when we have the stick held full forward (with 0 side stick or 0 aileron input) having the aircraft settled at a new equilibrium negative AoA, then apply a full boot of rudder (doesn't matter if the yaw CAS is switched off or on) to any side and have it rolling in the opposite side of the yaw (which is correct for negative AoA), just to see it starting to roll in the same side as the yaw as if the AoA became suddenly positive, but the lift continues to be negative? What logic does this have I don't know and if there's any reason why would a real F-15C react this way i'd greatly appreciate the correct answer...! Now in order to be more precise in what i'm saying, i've made up a short video where these inputs are illustrated and every reaction by the aircraft can be observed: I've only made this video for the F-15's updated flight model investigation purposes, not for criticizing or any other reason than to promote what has already been gratefully achieved and done well...! Thank you!:thumbup:

Period! And this happens every time you reach above 18 AoA on the HUD indication (although for some reason this indication is always about 10 degrees higher than the real AoA, but whatever...) when you fly above a certain indicated airspeed and altitude. So as Tharos said..., if you have any remnant roll rates before pulling above the said AoA, you'll end up increasing that roll rate and if you dare countering it by aileron only (because as some of you have already learned that the yaw CAS reduces compensation above a certain Mach number) you'll only increase the adverse yaw which will make matters worse. Just get used to flying it as you should and you'll be fine. Learn it's limits and what you should do above those limits.

Are you sure you didn't turn the arcade mode off by mistake and put it to simulation? Taking off, flying and landing the FW-190 D9 is not in any way harder than doing so with the P-51D or with TF-51 at the same level of simulation. Try doing some takeoffs and landings with TF-51 and after you are good enough, switch to Dora.

Couldn't be greater! Thx;)!

Thank you for letting me know! Sorry I didn't know it was asked already!

Hello, If you could add the following features/options in the Mission Editor, it would be great for some future DCS players: We would love to have a both sides opened hangar which we could fly through, added in the static objects list. The hangar's entrance should be 15 meters wide and it's length between 20 to 40 meters (at least 20 would be great). Secondly, if we could have an option or feature which can help us add multiple objects with positional constraints to each other and also be able to see them as a preview in the 3D world when they are being placed, would greatly reduce the efforts of adding objects! Thank you very much ED developers!