spyro23

So I finally got more time to fly Su-27 with PFM One of most annoying things I’ve noticed (as well as other community members) is crazy pitch down tendency when switching to direct control mode. I did some reading of forum posts (not everything) but I did not find satisfying explanation of this behavior. So decided to make small investigation as such behavior would make aircraft extremely dangerous to fly in real life and seemed like modeling fault. So I did read FCS description at: http://www.digitalcombatsimulator.com/en/products/flanker/?PAGEN_2=2 We do have block diagram of FCS and trimming law scheduling so it should be possible to find out what is going on here. Let’s assume level flight condition at constant speed without any disturbances causing intervention of FCS. In that case: · control stick inputs (ST) = const. · rate of pitch (ωz)= 0 · g force (ny) =1. Since rate of pitch = 0 then pitch damper output = 0 Since rate of pitch = 0 , and g force =1 then pitch autostabilizer output = 0 So stabilizer deflection (ϕ stab) depends on calculated Klong for given Pdyn and Pstat. (trimming law?) Now I’ve checked how much is stabilizer deflected actually (in external view) Its quite easy to do that because you have deflection angle markings on fuselage. For level flight deflection angle is from ~-2 deg. (pitch down at small IAS) to ~+2 deg. (pitch up at high IAS) – nothing unusual here. Switching to DIRECT CONTROL EMERGENCY mode disables Klong calculation and enables Klong man instead (from the diagram it appears to be constant but it is named man like manual??). Since we assumed that in our flight condition pitch damper output =0 and pitch autostabilizer output = 0 then (for level flight)deflection of the stabilizer should change proportionally to the change of Klong - (from Klong calc to K long man) when switching to direct control mode. In one special case when Klong calc = Klong man - the stabilizer deflection should not change ergo we should continue more or less level flight – so let’s find those conditions! The problem is that every time you engage DIRECT CONTROL EMERGENCY mode the stabilizer sets itself at about -5 deg. (pitch down) position in flight causing immediate flip over the airplane nose, blackout and crash. Stabilizer deflection seems to correspond with actual stick position being trimmed nose down by trimming law before we engaged direct control mode. This looks like huge design fault (I do not believe it is truth here) or more probably some error with FCS modeling in DCS. Since trimming law is not working below 230 km/h only, ergo: in basically whole flight envelope you have big mismatch in stabilizer deflection (for level flight) for given stick position between FCS modes! Once again I think this is wrong. How it should be working then? I can only suspect that: 1. Assuming Klong man value is constant then Klong man is wrong and it should be bigger to at least partially compensate trimming law and associated ST position to reduce nose down tendency when switching to DIRECT CONTROL EMERGENCY mode – the drawback of this approach would be that at some speed you would have pitch down tendency (to lesser extend then now) and sometimes pitch up tendency - not perfect but still better than current behavior and still dangerous in real life. 2. Klong man value is manually set by pilot based on IAS or Mach prior to engaging DIRECT CONTROL EMERGENCY mode to compensate ST position forced by trimming law – something like additional counter trim to trimming law which in my opinion is missing now in DCS Su-27 PFM My Russian language knowledge is pretty much nonexistent and I have no access to Su-27 flight manual but let’s take a look at panel where you flip the switch to enable direct control mode There is some button (knob?) and indicator next to mentioned switch (Mach number?)– maybe there is no fault per se in FSC modeling but we are missing some features actually? Maybe all we need to have added is possibility to manually set Klong man ? according to Mach number? before we engage Direct control mode.

Really? Flying and fighting over the modern cities with apatrment buildings, harbors that look current etc., taking of from runways with ILS, PRMG equipment etc. fits mote to this enviroment than F-15? I...just don't know how to respond to that. The messy midpoint that will last for some long time I think. There is no moderation what stuff is being developed as far as I know. Once WWII will be more or less sorted we will have Korea, Vietnam projects and so on that will last forever. As far as why should you go buy another sim when you like DCS? - why shouldn't you buy if you enjoy WWII sims? I'm not sure which post you are referring to. Actually VEAO plans seem to prove my point. If you look at their plans the only modern combat aircraft they plan to do now is Typhoon along many warbirds. Moreover they seek military contracts to make stuff and then cut it (in a bad way) and sell to us pseudo-simulation (Typhoon again). Sure, they mentioned Harrier, Falklands and plenty of other stuff, yet their first module is not finished now. As far as I'm concerned there are only warbirds on VEAO plans.

A little bit yes. You see, adding warbirds that do not fit, at all, into current battlefield (both regarding map, year and other equipment present in the sim) is not combat simulation but Si-Fi simulation of alternative universe. I would not mind if some company have bought DCS engine and made separate and proper WWII sim (with all units, maps etc.) Instead we have what we have now, altogether with very vocal part of community that wants more WWII (or now civilian planes:doh:) in DCS while there are there at least 2 preety good WWII sims (also good civ sims). Sarcasm on: Hey WWI fans, who wants to fly Zeppelin !?:Sarcasm off. I'm just a bit afraid that for developers, it would be much easier to do some WWII warbird and sell if fot 50 $ than do a proper module of modern fighter and sell it also for 50$. The amount of research and work needed to make both modules is quite easy to compare and it doesn't look good for modern fighters. After all for majority of developers it is a business. Keeping that in mind we may never again have real "DCS" only Si-FiSim.

Well, idea of having civilian aircraft inside DCS is IMHO strange for the lack of better word. The "C" in DCS should keep meaning something. The way I see it: DCS is already being dissolved by WWII(and a little bit by trainers), adding civilian aircraft would not be good for it, I believe. So big NO for civ aircraft from me.

No MiG-23ML only MF BMP-1 BMP-2 (retired) BRDM-2 Grad Gvozdika Igla Kub Osa S-125 Shilka Zu-23 OHP frigate HMMWV Leopard 2A4 and 2A5 Sniped

Surely +1 Lets hope we won't have to wait for 3rd party map to have Poland in DCS as hinted by some guy that loves giving hints.:smilewink:

I’ve noticed some possible bugs concerning Canopy freezing and Pitot system freezing During flight in atmosphere in icing conditions (as stated in manual: temperature is between 0oC and -10oC (32F / 14F) while your IAS is between 400 - 500 km/h) with both Pitot tube heaters off (CL74 & CL75) as expected I’ve noticed reading discrepancies for altitude, IAS, TAS and M (all eventually went to 0) but little to no discrepancy with reading of vertical speed values. Additionally I’ve lost reading od AOA (needle stuck at 0 position)So: Bug no.1 Freezing conditions are present in game when temperature is between 0oC and +10oC not as stated in manual -10oC (misprint) Bug no.2 AoA is affected by freezing but needle goes to 0 deg instead of freezing at current AoA reading for example 8 deg. After this I tried to see what will happen if only aux. Pitot heater or main Pitot heater system will be on (CL75 only or CL74 only). As previously I lost all mentioned readings but switching Pitot tube selector lever (CU44) to auxiliary or main position (in second case) did not remedy situation – I still didn’t have readings and I should have them in one of the Pitot systems. Bug no.3 auxiliary Pitot tube heating and main Pitot tube heating seem to be serially connected to both main and auxiliary Pitot systems. As far as Canopy freezing is concerned I was not able to experience it at all. Instead of this I’ve noticed that ASP-PFD shut down itself (no piper and fixed net present, no backlight on ASP whatsoever) Using Anti-icing system lever (deicing front cockpit) did not help. After accelerating to unfreeze ASP switched back on itself. It also came back on when only both Pitot heaters ( CL74 and CL75) were switched on Bug no.4 Pitot freezing effect seems to be somehow wired to ASP power supply. Bug no.5 Not able to get Canopy freezing at all.

You meant Dusty Crophopper, right?:lol:

It looks like MiG-23 HUD to me.

I want a Hawk

New flares itself are looking really good. On the other hand, smoke trails they now produce is a big step backward IMO. It is no longer "shattered" for a lack of better world (like flare is no longer rotating in the air). Moreover smoke trail seems to dissipate too quickly.

It is not a bug, it is a feature. You must remember that MiGs engine is controlled by the hydro-mechanical controller not the DEEC or even EEC. For various reasons nozzle had to be opened before augmentor was lit. Try to search forums - some ppl explained this already, I believe. :doh:Apples and oranges Sir.

Empty S-24 launchers/rails separate from pylons at the same time as launchers with rockets during too high G maneuvers. As I understand uncontrolled weapon separation is due to overstressing part of the pylon lock or weapon attach point so the heaviest weapon should separate at lowest G load, ergo empty launchers should not separate under high G at all, or at much, much higher G load. Similar situation is with UB rockets– if you have for example load: 2x UB-16 + 2x UB-32 you will lose all 4 of them simultaneously like the mass of pods does not matter. As far sa bombs, Grom missiles and fuel tanks are concerned - It seems that overstress feature does not work with them (tested up to 11G)

I’ve noticed problem with a landing gear behavior on the ground when stationary. If you move handle to retract landing gear and the aircraft is stationary all three struts will collapse/retract. I think that since main wheels retract inward (and a bit forward) to the fuselage it should not collapse because of friction between tires and ground, in other words actuators are most probably too weak to retract landing gear. Additionally because of the auto-brake feature we can disregard forward component of the strut movement. If then you will move LG handle down, the main gear struts will extend lifting the whole aircraft. On the side note: landing gear doors could be damaged and whatever is under centerline pylon could not sink under ground level when landing gear collapses – I don’t know if it is possible within DCS engine.

You LN Guys have thought through literally every aspect of MiG simulation, didn't you? :thumbup:

Unfortunately I could not find good photo showing "Bis" throttle at full AB position but I found one from "MF". In "MF" throttle grip is different a bit, but the throttle quadrant / base is basically same as in "BIS". Since the angle of the photo is a bit different I drew yellow line parallel to the panel in the background.

According to available data KM-1M is 0-130 class ejection seat but I'm still able to safely eject from a stationary aircraft every time. I do realize that sometimes successful ejection can be made outside seat envelope but it would be nice to have seat limits (both lower and upper) simulated.

It is not lag problem, in my case throttle grip does not move beyond mil pwr at all when afterburner is selected.

Missing texture of outer pylons with droptanks (Finnish livery); Missing texture of engine afterburner so flame is visible at some angles outside exhaust nozzle.

It seems that throttle movement is not animated above military thrust level. Acc. to labels throttle should be much more forward when AB is engaged. Printscreen below taken during full AB

Purchased, now impatiently waiting for the 18th:joystick:

That is clear to me from the very begining. The question is whether there is a interlock or something that will force the AoA indicator to show 0 deg (or force vane to 0 deg position) during taxi? Again, pls compare AoA indicator on this video: and this:

On all videos published so far I’ve noticed that AoA indicator was showing ~0 deg during taxi which seems odd to me. AoA sensor (DUA-3) is a vane type sensor where vane is freely adjusting itself to the actual airflow. At low speeds (ie. during taxi, beginning of takeoff run etc.) airflow should be too weak to lift vane to 0 deg position ergo indicator shall show some negative AoA. If you watch this video you will see that during taxi the AoA shown is around -7 deg (starts at 1:4) Could someone verify whether or not it’s a bug? I’m abroad now and I do not have access to manuals, unfortunately.

WOW! Screenshots looks amazing. One note regarding payload. As I found on the other forum: before nuke was loaded the main landing gear doors had to be removed due to diameter of the bomb. You can see on the drawing below that main gear doors are missing. I think it should be no problem to implement this since, I believe, this feature is already present for main landing gear struts.

Awesome! :thumbup: