My observed various bugs or potential bugs.

[rosseloh]

Finally got around to doing a few flights with the MU-2 in XP12. For clarity, I am using CapitanCrash's modified airfoil configurations and tweaks, so I *have* modded the ACF file - that shouldn't invalidate these observations, but if it does, so be it (none of them have anything to do with the flight model, which for the most part feels fine). Of course, as always, I apologize for any of these that have already been reported! (I did look through the first six or so pages of the forum to check)

Here's what I've seen thus far.

Things that may not be bugs but seemed off to me:

1. With Continuous Ignition set to off (as per the procedures in the real manual; I don't see anything about what to set it to in the TOGA Sim checklist), the engines will never light off. I've thus far only tested this while doing the NTS check during start, as I have not done a "second flight of the day" yet. I will check the next time I fly. What happens is, per the normal NTS check startup procedure

• you hold Unfeather, then hold Start
• the starter spins, fuel flow comes in, EGT comes up ever so slightly (if it's simulated I assume just from compression heating)
• but the starter light never engages and the fuel never ignites - *until* you release the Unfeather button. At that point the light comes on, and the start continues seemingly normally.
• As far as I've gathered I'm pretty sure ignition is supposed to come on on its own during the startup sequence - that's one of the things the Run-Crank-Stop switch does (since putting it to Crank disables ignition and/or fuel introduction?). But that's just from my reading of the manual, maybe I'm wrong!
• in contrast, the start goes as expected (including the NTS check) as long as continuous ignition is on in some way (generally Auto)

2. The Glass version of the plane flies on the GPS just fine in NAV mode, without using GPSS Roll Steering. This one I assume is expected behavior... However the Roll Steering button still exists on the panel.

3. The Glass version can track the G500 Vertical Speed bug in VS mode whereas the other models do not have this function and only hold the VS you have at time of engagement. This also may be expected? I'm not complaining, despite being fine with control-wheel steering options in most planes in this one it seems awfully janky, almost like the AP isn't quite trimmed out despite it being trimmed when I hand control over to it (this could be realistic, I'm not sure), so I am happy to have a proper VS mode where I can dial it in.

4. The toe brakes feel like they take half a second or more to apply even with the brake rate thing in the settings set to 0.01. I have hardware toe brakes and I'm used to getting basically a one-to-one mapping of brake force to pedal position. In the MU-2, even if I slam them to full, I don't get any indication they're applied at all for a short period of time (at which point they lock up as expected). Maybe this is normal.

5. Static elements (chocks, pitot covers, yoke lock) don't appear to persist after quitting the sim. Maybe intended, but seems a bit odd if so - what's the point of simulating them if I have to put them on before I take them off on my walkaround?

 

Things that are probably bugs:

1. There is no clickspot/manipulator for the command rsg/g500/cmd/mfd/knob_push for the Glass version. I can get around this by mapping a key in the interim.

2. I cannot monitor NAV idents. Clicking the buttons on the audio panel does nothing. (I wanted to do this as I noticed some interesting behavior on the needles at extreme distance from a VOR, and was curious if you had implemented libradio into the plane; I'm guessing not since the DME doesn't seem fuzzy at all, but noticed this bug while I was at it)

2a. (There might be other issues there, but the NAV idents are the only one I've confirmed)

3. The audio panel does not light up except for the marker sensitivity lamps. I have seen this one was reported and confirmed already, but just for posterity... This is the case in both the GNS and Glass variants.

4. The flight timer on the transponder unit displays 60 in the seconds field for a half second or so after 59, before switching to 00 as it should. For example, the time going from 00:39:59 to 00:40:60 before switching to 00:40:00.

5. in the GNS version, the yoke shaker animation plays every few seconds with battery power on. I did not notice it happening once the engines were on or generators were on the bus, but I did not test properly so I don't have details for you. Update: saw it happening during taxi. So generators were definitely on bus. No sound, just the animation. This does not happen in the Glass version Yes it does.

6. You already know about the slow reverse application, especially noticeable while adding reverse after touchdown. But I've seen it as well!

7. The yoke lock prevents you from showing/hiding the yoke with the clickspot. I neglected to test the keybind. It doesn't matter what state it was in when you put the lock on (showing or hidden), but you can't change it at that point until you remove the lock.

8. In the GNS version at least (neglected to test in the Glass version), after using GPSS roll steering in a flight and then disconnecting the AP without switching back to regular heading mode, the GPSS roll steering lamp stays lit even after the battery is turned off.

9. I noticed that the two custom commands for "add_left/right_roll_trim" don't appear to work. Instead I just mapped the default roll trim commands and they worked as expected.

 

 

Finally, not bugs at all, but just questions. Are there datarefs/commands for the pitch wheel and roll knob on the autopilot? I wouldn't mind lacking a controllable VS mode if I could just leave it in Pitch mode and control it manually with external hardware (the virtual wheel is just a bit of a pain, my own issue, I know). I see a pitch wheel command in the documentation but it doesn't appear to work, and I don't see anything for roll.

 

Thanks Tom! No hurry of course, I think I'd prefer having the old 737 back in my sim versus these little issues I can work around here!

Edited June 25, 2023 by rosseloh

[tkyler]

Thanks for the inputs @rosseloh, this post is logged and very good feedback.  Definitely some of those bugs are known and on my list already.  I certainly need to go over some of these items again,  I do know that XP12 and recent updates have altered some behaviors, particular with GPS stuffs that I expect to have to re-test and adjust.   I talked to Philipp at the FSExpo about the reverse issue and hopefuly he'll take another look at that.   I'm reluctant to override the engine model as its all or nothing, so if I do that, I have to simualte the entire engine which would be a big job, whereas Laminar is about 95% there, so I really want to get them to fix this on their end.  That reverse thing drives me nuts. Thx for your patience, I'll keep toiling away steadily and eventually we'll get all this stuff going.

-tkyler

 

 

 

 

Edited June 28, 2023 by tkyler

[rosseloh]

Thanks! You could potentially consider licensing libturbine from Saso if you decide a custom engine model is the way to go - but I don't know what that would entail to implement, what it would cost you, or if it would be worthwhile! Just that it would be a good call for the overall simulation if you went that way....

 

 

Another thing I noticed is that when above 25,000 or so, the engines can't put out enough air to keep the cabin pressurized, and above 26k/27k you start to get into the cabin alt warning area. The manual makes it seem like the thing should be able to hit 30k/31k at max diff with a cabin alt of around 10k, but what I've observed is the differential pressure can only get to max when below 25k-ish. This was on a very standard day (ISA was somewhere around 0 to +1 IIRC)

This could be related to the engine changes I made as part of Crash's mod, however, so don't focus too hard on that one until we're sure it's a problem with the actual engine model and not my mods.

[rosseloh]

I've done a few more flights (after far too long out of the sim and especially out of the MU) and have a couple more observations. Note that I have now reinstalled the plane fresh and do not have the engine mods applied anymore - the only ACF file mod I've done is to add the weight stations so I can load payload properly in XP12. Hopefully if I actually get these written down they can sneak into the next (soon:tm:) update.....maybe not.

1. Unfortunately I don't have repro steps but I've on more than one occasion been able to get the ALT ARM light stuck on on the FCP. Even if ALT is engaged (and arm is not), the ARM light stays on. It's inconsistent and like I said I have no idea how I've actually triggered it, except that when it happens it appears to be when I've disengaged ARM by pressing the button a second time, while it's near/in the process of a capture. But I'm not sure on that.
2. The animations and sounds for various button clicks (mostly noticed on the GPS units, but maybe it's elsewhere too) seem awfully slow. Like I'll press the button, the "down" sound effect will play and the "up" sound won't play until half a second later. In reality this would only be the case if I was holding the button down before releasing, which I'm not.
3. I can follow a GPS NAV course via the NAV button even in the non-glass model. As far as I'm aware this should not be possible, because otherwise what's the point of the GPSS ROLL STEERING function. But, I suppose welcome to Laminar autopilot quirks!
4. We all already know about the engine model issues but I just wanted to detail what I've seen in case it helps or at least gives us something to test against (in XP12.1.1 - so even more changes since the last time I flew a lot, I'm sure!):
   • Beta range seems totally broken. With the power levers in ground idle and the condition levers at the (well, technically, below) taxi stop, the plane won't roll at all. I need to give it nearly flight idle power to break away at all, and going into beta range more than a couple of millimeters of lever travel will bring the plane to a stop right quick. I have the best taxi experience when I have the condition levers fully forward and the throttle jumps back and forth between flight idle and high beta as I need to speed up/slow down.
   • Reverse is also messed up. I know we know about this one. But oh boy that can get pretty spicy if you're trying to use reverse on landing as the governor(?) goes crazy and the props go in and out of reverse a bunch.
   • Power in flight seems fine though of course I can't tell you if it's tuned to the numbers or not.

I wasn't taking notes as I flew this evening; the engine issues were the elephant in the room by far, so I'm glad to hear those should be hopefully licked soon. I will say with Gizmo being deprecated, if you're switching everything to C++ and if you happen to have enough raw data on the engine model itself, I'd highly recommend talking to Saso/Toto and seeing if you can get libTurbine licensed and implemented and get that engine simulation entirely divorced from whatever Austin or Phillipp decide to do on a given day... Just my personal pipe dream though, probably doesn't make sense from a business perspective.

 

 

Finally I know not many people actually fly this, but I love a good turboprop and we are very, very lacking in XP12 right now! If you need a hand to do some grunt testing work or number checks on the update, please, let me know.

 

Oh, and a long-shot request: obviously we don't have any weather radar right now, but if you're ever in the mood to mess with the 3D model....any chance of a version with a GNS430 (singular), traditional COM2/NAV2 set, and the radar display like in the OEM version? Or two 430s, I guess, if it's possible to fit them on the panel, but I'm not sure how that would work out. I like having *a* GPS in the modern sim since traditional radio nav is going out and fast, but I also like the idea of having a radar in my fast-but-maybe-not-able-to-outclimb-the-weather turboprop...

Edited August 18 by rosseloh

[meierzwo]

I'm using Honeycombs Alpha and Bravo Equipment and MFG Crosswind Rudder Pedals.
Taxi is sometimes very slow and I have the same experience as you, but it seems to be a problem with the Brakes, not fully released. I have this often after Landings, when leaving the Runway and changing Throttle and Props to Beta and Taxi. The Plane slows down, is very slow or stops. But giving Full Brakes, waiting a few seconds before releasing the Brakes solves the Problem mostly. And sometimes it is the Weather and the Terrain. I can stay in Beta just below Flight Idle most of the Time, a little bit more Prop is needed sometimes. It's not the Hardware, the Moo is the only Plane with this Taxi Problem. If the Keys "v" and "b" on the Keyboard are assigned with the Brakes (Default XP Setting), hitting them accidentally may also cause that Problem.
Reverse is working for me. It kicks in late and could be more effective but I did not see any governor kick in. Torque and RPM is stable once Reverse is established.
The Bravo Quadrant has only switches to apply Reverse. They are set to "Move left (right) power lever to reverse from ground idle". That seems to work. Prop Levers full forward for landings. And the Button Sounds and Animations seems okay on my Side.

[meierzwo]

ILS Approach at EDDG. No Brakes in use, only Reverse. Look at the Ghost Throttle to see the Positions.

 

[rosseloh]

Yeah that's a lot smoother than mine behaves - I see torque and EGT jumps all over the place when reverse finally kicks in. It would be funny to watch if I wasn't trying to maintain the centerline while it was going on. I do see a bit of a fluctuation on yours (the torque decreases a couple seconds into reverse), so it's not entirely gone on your end...

[meierzwo]

I use Reverse often for Push Back with Props set to Taxi. Did the Job.

In the Landing shown above, I was in Flight Idle first and then set the Throttle to Reverse. Maybe this triggers some Governors before Reverse kicks in. Once it is established, it looks stable. Normally, Throttle is short above Flight Idle and I'm going to Reverse in one Motion after the Wheels touch the Runway.
And it is from Flight Idle into Full Reverse with my Hardware. I don't know how the real Plane will handle this.
But I think, it is similar as with Full Throttle at Take Off. If you set 100% Torque to fast, overshooting it, a Governor kicks in and reduces Torque. Could be the same in Reverse.
Could take a few seconds before Prop Blade Position, RPM, EGT and Torque are stable. So this little fluctuations could be normal.
But your Situation is not normal with Torque and EGT goes up and down.
 

[rosseloh]

After touchdown I go from slightly above flight idle (wherever I was on short final) straight to Ground Idle, and then I wait a second or so before hitting reverse.

 

Regardless - all of this is a bit of a mess and I know the next update includes engine tweaks so I'm just mentioning it for posterity, not to actually report an issue that I know has been well reported!