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M2K-C issues

By @LeCoyote
    2025-02-20 21:29:15.237Z

    Hi there,

    I've just bought the M2KC from you, and after a short flight test I've got a few issues to report.

    • engine RPM discrepancy: the value from the numbers is about 20% lower than that of the needle
    • ground idle sits at about 27% (numbers), it should be around 50%
    • fuel burn sticks to idle values up until N reaches 50% (numbers)
    • the broad inverted T on the hud (takeoff/maximum pitch indicator) should line up with the horizon when the aircraft pitch reaches 13°; it is way too high as it is
    • the A/P disconnect sound is incorrect
    • disconnecting the A/P should not reset the altitude selection
    • engaging the A/P without modes should not level off at the current altitude (those 2 issues are clearly a consequence of the inner MSFS A/P)
    • in APP mode, the AoA brackets appear to be fixed right below the 3° slope indicator
    • no AoA digital display (alpha) in APP mode
    • pitch response extremely twitchy at lower speeds, whether the joystick sensitivity is linear or flattened (it feels like overcoming the FBW PID results in an exaggerated response)

    The A/P looks pretty basic for now, I guess its actual features will come later on so I'm not reporting on these just yet.

    Other that that the artwork is great, the M53 sound is beautiful, and I'm looking forward to future improvements!
    Cheers

    • 5 replies
      1. We are tracking this issue
      2. This is by design. Making ground idle any higher will result in the aircraft accelerating at IDLE power. Its a sim limitation in msfs.
      3. Not too sure what you mean, can you elaborate?
      4. Just noticed it is in fact set too high, will review.
      5. No references for A/P Disconnect sounds that we can freely use
      6. Also by design. Not resetting the altitude selection creates issues in MSFS with Altitude Hold.
      7. As you mentioned, this is a consequence of MSFS AP. Not much we can do there.
      8. By design, we fixed it at 3.5 Degrees which give us a correct AoA on descent
      9. Can you confirm alpha is always visible in APP Mode? Will add if so
      10. We continue investigating. The issue is that modifying the PIDs to make approach less sensitive will dampen significantly other phases of flight. Unfortunately the FBW implementation in MSFS is very poor. Our recommendation now is adjusting the control curves slightly for less sensibility

      Not planning to expand much on the AP system at this time, will remain as alt hold/select and HDG Hold.

      1. L@LeCoyote
          2025-02-21 00:24:44.512Z

          Hey there, thanks for the quick response!

          Sorry I cannot use the auto-formatting of lists, it resets all the numbers.

          Here goes:
          2. Well, I remember raising this issue with another jet (Dino's T45-C), and IIRC altering the N1/Mach on thrust table to produce 0 thrust until higher values of N1 fixed the issue. It was a pain to get it right but it can be done!
          3. Sure. When advancing the throttle, the fuel flow indicator remains at about 11kg/min up until N reaches 50%. I suspect some tweaking in engines.cfg could fix that too. Besides, fuel flow overall is too small. Typically, low level nav (below 1500ft AGL) is flown at 450 KIAS with FF around 50kg/min; in the sim we get less than 40. Similarly, cruising at .95 at FL300ish gives a cruise in the 35~40kg/min depending on loadout; the sim currently yields less than 30 kg/min. I know how hard it is to get consistent values for this from MSFS!
          6 and 7. Well one way of handling this would be to disconnect the cockpit setting from the A/P, eg. by having the cockpit altitude selector feed an LVar, and a custom logic that either feeds that value or the current altitude to MSFS's A/P, depending on what's required. The real A/P has two different modes for altitude hold and capture IIRC (plus the "fly through" mode with the asterisk FPV target), so that would be handy anyway.
          8. Um, I wonder how that can work, what with AoA depending on speed too. Having the bird between the brackets does not result in a correct AoA if you're flying too slow or too fast.
          9. I wish I had a better source, but the aircraft modeled in DCS has it, and IIRC it was used by the French Air Force at some point, so I would believe it to be correct, but I am not 100% sure. It would make sense though, as the analog AoA display is barely visible from a normal sitting position.
          10. As it is the aircraft is more sensitive at lower speeds, which is problematic. I guess the only way it can be alleviated is by implementing custom PIDs outside of MSFS's flawed FBW logic.

          While we're at it, let me add:
          11. The radio altitude mode selector effectively adds the height information in a smaller font below the baro altitude, it does not replace it. It will show eg. "1500 H" to avoid confusion, or "*****" when the aircraft is too high or banking too hard for the radio reading to be reliable.
          12. The fuel logic is somewhat wrong. The aircraft cannot burn fuel directly from the external tanks: she has to burn some from the inner feeder tanks first to make room for fuel to be transferred from the external tanks. This is what the "AFF DETOT" switch is there for: the pilot will manually set the DETOT to the amount of fuel they know to be onboard prior to startup, and the aircraft will then decrement it based on actual fuel burn regardless of how much fuel is sensed on board. Also, the readings on the two vertical gauges don't really add up to the total fuel gauge. For example, if you set the fuel to 28% in left and right main tanks (center tank empty), you get about 800kg total fuel, but the gauges show about 420kg on either side. Finally, regardless of the BINGO setting, the "NIVEAU" alarm annunciator should light up when fuel reaches 2x250kg.
          13. The red beacons (both top and bottom) are INOP regardless of the ANTI COLL switch position (the white ones on the fin work though)
          14. In what you called the BDHI, "Cv" means "Cap vrai" ie. "true heading", as opposed to all the other functions under a "Cm" arc for magnetic heading. Also, VOR/ILS should not be mapped as a separate mode from TACAN: all airbases have a TACAN, and the ILS uses the TACAN's DME it doesn't have one of its own. Therefore both modes must be able to work simultaneously in order to get proper distance information while on approach. On a side note, the "M/A" knob on the VOR/ILS does not stand for Manual/Auto but Marche/Arrêt (ie. on/off).
          15. When A/P is on with AFF only (no horizontal mode), when hand flying a turn, rolling out to 0° bank will have the A/P bank the aircraft (in my case, always to the left for some reason). I can think of no reason for this, it is completely unrelated to the position of the HDG bug, not sure what's going on but that looks like a genuine bug.
          16. The FPV suffers from the same weird bug as a few other military addons: its vertical position seems to depend on bank. I was able to put the aircraft in a position where it was climbing and the FPV was above when banking right, but below the horizon when banking left, while still maintaining a positive rate of climb. My bet is there is a sin/cos(bank) somewhere in the code that should not be there. Oddly enough, this also depends on the heading. I was flying at FL350 heading north, A/P holding altitude. I initiated a left turn, the FPV went below the horizon until heading ~300, then above to a maximum at heading 210, then back down again when passing heading 120. When turning right, those variations are reversed. It strikes me that the threshold values are 30° off sign changes for cosine, especially when 30° is the commanded bank angle. Something fishy going on here but I haven't started digging into the code just yet.

          Well that's it for tonight, I'm going to grab some shuteye. I know it's a lot, but rest assured that my intention is only to help making this aircraft even better than it already is! <3 I love the 2000 and I'd been waiting for a proper rendition in MSFS for a while now, so thanks for filling that void!
          All the best

          1. Miltech Simulations @MiltechSimulations
              2025-02-21 06:33:24.235Z2025-02-21 06:46:19.077Z

              Thanks for the feedback - some of these points are worth reviewing.

              However, please keep in mind that due to various reasons, this product does not intent to replicate accurately any aircraft, and several functions have been simplified or adapted for usability in the sim.

              This is the case, for example, with the APP glideslope indicator on HUD. We are assuming an approach speed of 145-155, at which aligning the FPV with the indicator will result in a correct AoA. The brackets do not move for simplicity, by design.

              Similarly, the functioning of the BDHI has been adapted for clarity and simplicity in MSFS.

              Similarly, engine values are designed to produce correct acceleration effects, and ultimately a correct flight model, over matching exact engine performance parameters. We could fake the readings to match the reality, as often required in MSFS, but there is little benefit to that

              1. L@LeCoyote
                  2025-02-21 18:36:48.907Z

                  Hi there,

                  I understand the need for simplification, this is not a study-level add-on after all, and I am on board with this.
                  Still, the approach speed assumption feels problematic to me. The aircraft is designed to land at 14° AoA. The 145-155 speed range will only work for a limited range of landing mass. It would be really nice if it worked as intended :)

                  I understand your comment about the BDHI. I just wanted to highlight that, when ILS (LOC/GS) visualisation is implemented, it should not rely on the "Cv" mode since it would make the TACAN readings unusable.

                  Regarding the engine, I am not saying the readings need to be faked. For example, I've come up with this:

                  n1_and_mach_on_thrust_table = 0.0:0.0:0.9:1.5,0:0:0:0,20:0.005:0.006:0.005,25:0.01:0.012:0.01,30:0.02:0.024:0.02,35:0.03:0.036:0.03,40:0.04:0.048:0.04,45:0.05:0.06:0.05,50:0.07:0.084:0.07,55:0.09:0.108:0.085,60:0.12:0.144:0.1,65:0.18:0.216:0.13,70:0.24:0.288:0.19,75:0.3:0.36:0.24,80:0.37:0.444:0.3,85:0.43:0.516:0.37,90:0.52:0.624:0.45,95:0.66:0.792:0.56,100:0.82:0.984:0.72,105:0.93:1.116:0.83,110:1:1.2:0.9

                  If you combine this with an idle of 50% N1/N2, you get an aircraft that will NOT accelerate on its own at idle power (except with no weapons and little fuel of course) and with a normal N1 reading. Please note that this is a very crude, hasty proof of concept: the power curve is a bit weak at high values of N1, but it works and can be improved on. The engine sound samples would probably have to be remapped though.

                  Thanks for the heads-up regarding the beacon lights, I was focused on real-life behaviour (one switch only) and had not noticed you had implemented them differently (same with the landing/taxi lights, but I found those eventually). I'm not sure what the benefit of these changes is, but I'll survive ;)

                  Last but not least, I'd be happy to contribute if you feel so inclined!

                  All the best

                • In reply toLeCoyote:

                  Regarding the red beacon, I cannot replicate on my end. Works fine here

                  Beware that the White Strobes and the Red Beacons use different cockpit switches