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Engine Start Issue


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Attached is a video of me failing to start the right engine. I have had this happen more than once on one or both engines. I can't tell if there is a way for me to troubleshoot in sim or if it's a bug? 

Here is what I notice: 

Left engine starts, shuts down, starts again just fine.

Right engine spins, gets fuel pressure, EGT just barely increases but it seems like combustion never catches.

I tried engaging Continuous Ignition, but saw no change.

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thx for the report.   It seems I myself have come across this is the past, though have trouble repeating it...and in addition, have not seen this for quite some time....so I'm going to start by saying I don't think its "Just you".....but follow that on with "I'm not sure what causes it" either.  Historically, its been really rare for me...only once or twice in hundreds and hundreds of starts during development.

You mentioned start up then shutdown....and IIRC (cause its been a while since it happened)....it seems it was associated with engine shutdown and restart.   This could be a Laminar bug.

The key is to find a repeatable procedure that results in the same outcome every single time and I haven't been able to do that yet....but I will look at this again and try and repeat it.  

When it would happen.....and the reason I say it may be a Laminar bug....is all the datarefs I  was monitoring indicated the engine SHOULD have been running...was receiving fuel, was ignited, etc, but it just wouldn't accelerate.

If you can find an operational sequence where it happens every single time, I'd love to know and try and repeat it and take a look at it.

-tkyler

Edited by tkyler
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22 minutes ago, tkyler said:

If you can find an operational sequence where it happens every single time, I'd love to know and try and repeat it and take a look at it.

I'm going to keep flying the module, so I'll let you know if it's repeatable :)

Yesterday I couldn't start either engine after trying to use the "first start of the day" checklist, so I assumed maybe I should just use the quick list. Then, this morning, I had that issue starting the right engine. 

Now that I know it might not be "me" I'll just reload the plane when it happens, but if I can get it to happen reliably I'll let you know. 

My only thought - is there anything specially coded with the propeller "on the locks" unfeathering stuff? I always move the condition and power levers through their ranges and hit that Unfeather button and stuff to try and make sure I have the props flat, but considering it's an imperfect "check with your eyes" sort of test I wouldn't be surprised if some special number underneath doesn't meet criteria that the engine start computer needs or something?

I'll try to simplify my start procedure in the future to isolate buttons and levers I move that could be the culprit.

Thanks!

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Well without a doubt the condition levers play into the fuel flow so a hardware setup could come into play depending on its configuration...the condition lever ratio nees to be about 0.4 or higher for engines start.  Not so much the propeller on the locks or unfeather, that really doesn't play into the 'ignition' process. 

One thing you could try is simply to unplug all hardware and use the keyboard and mouse to move all the levers and see if it starts normally that way....at the least it may be an additional data point.

-tk

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As a new Owner, I have this Issue too. I can start the right Engine but not the left one. No Difference in Startup Sequences or Button Settings. Fuel Flow but no Ignition and the the Engine won't start. Master Caution goes on and the "L SRL Fail" appears.  Ignition Cont Switches are set to Auto.

I sometimes have this Issue with other Planes too.

And one thing. It's a Turbo Prop, so Mixture Levers should have no Effect. From my copied Bravo Profile, the Mixture Levers were still set with Mixture Control and Fuel Cut Off with the Detent Switch. It HAS a Effect. I was not in Fuel Cut Off but going from Rich to Low Mixture cuts off the running Engine. I deleted all Bindings for that but the left Engine will still not work. Hmm, someone sold me a broken Plane. :D

Okay, after trying another Plane and reloading the MU-2, none of the Engines won't start. Restarting the SIM does the Job and I'm on my first flight. I also think there is a bug in XP12 with the Engine Types.

Very nice Plane indeed.

 

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5 minutes ago, meierzwo said:

I was not in Fuel Cut Off but going from Rich to Low Mixture cuts off the running Engine

In the past (long ago), it used to be that any mixture value below 0.5 would cut off the engine.  This was Austin's simplified model for "low/high" idle in turboprops...but when that model was created, Austin did not really consider fixed shaft turboprops and was essentially working off of the PT-6 paradigm.   Now that has been enhanced to be more flexible, but still the "mixture ratio"  really represents the fuel reaching any engine and not necessarily the "mixture lever position"...so it is applicable in the "stochiometric" sense though not so much in the "typical nomenclature" sense.

8 minutes ago, meierzwo said:

I deleted all Bindings for that but the left Engine will still not work. Hmm, someone sold me a broken Plane

or  maybe  a broken simulator?  :)    If you did this in the same "flight session" without reloading the aircraft, then it wouldn't surprise me if it did not work.   I myself have been very guilty of this during testing, forgetting to reload the aircraft and stuff not 'binding' causing me to chase phantom bugs. When a plane loads, a whole lot of initializations and "bindings" take place....and the only way to get a really clean "reloading" of an aircraft is to reload it via the developer menu, or restart x-Plane.   The nominal way for us developers is to use the developer menu, but for end users, that's a bit odd and so many times, they just restart "the flight"...which does not always initialize everything properly in my experiences.  (which is why the reload aircraft menu item was added I think).

I will say I have not seen the "one engine won't start" bug in a long time.    IIRC, it happend mostly when attempting to restart an engine after shutdown in the same flight session and every single variable that should be 'set' to indicate a running engine was set properly.   It was/is enough for me to think X-Plane has an issue but in order to take that to Austin, it needs to be 100% repeatable and narrowed down to a smoking gun config, or else Austin won't really look at it because I control so much with a custom plugin...and when we do that, Laminar tends to "wipe their hands clean" of any issues.

I won't lie, the Bravo hardware has been a major PITA for me.   :P   Here's the funny part....hardware setup has been a PITA for Honeycomb too....I spoke with the CEO at Oshkosh last year about it.  This is exactly why they provide the profiles they do, in an attempt to alleviate the burden of a confusing setup from the end user, but in doing so, they end up providing "opinionated" configurations that cause issues with the Moo.

-tkyler

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  • 1 month later...

I am at a complete loss. I for the like of me cannot start the engines. Now I’m confused where the power levers should be sitting and also the conditions levers. Any advice on correct procedures step by step would be greatly appreciated. Oh I’m confused with this lock and unlock props bit as well. I don’t see the prop blades move whatsoever.

Thank you in advance. I hate using that quick start method in XP12.

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I've found a solution.. Provided that I at the start move the Condition levers by hand first and place them back at the taxi indent, I can then use the control on my Joystick to further use the condition levers.  The condition lever lock is touchie. To be able to move the condition levers with the mouse, I have to move the lock up and back down first otherwise the mouse will not move the condition levers (ie no symbol that enables the movement).

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Good afternoon,

I have tried to get this plane to start up for the past week and i followed all the instructions  on the pdf file that i received from x-aviation and nothing seems to be working. Can you help me figure out how i can get this plane to start or is there a video or website that you can recommend? x-plane 12

 

Thank you

Owen

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15 minutes ago, Tomlinson said:

Can you help me figure out how i can get this plane to start

Do you have a Honeycomb Bravo hardware per chance?      The most common culprit is hardware that is mapped to "mixture" and this hardware sets the mixture value to 0.  The Honeycomb stuff sometimes have preset profiles for their levers.   This 'mixture' value in X-Plane, doesn't really mean mixture in the 'recip engine' sense, but rather "fuel flow to the engine", so its applicable to turboprops too.

The second most common culprit is a lack of fuel in the center tank, which feeds the engines.  

For a first troubleshooting test,  I recommend you remove all hardware and try to start the aircraft using only the mouse, making sure you have fuel in the  center tank.  If that works, then we can focus on hardware.

-tkyler

Edited by tkyler
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3 hours ago, tkyler said:

Do you have a Honeycomb Bravo hardware per chance?      The most common culprit is hardware that is mapped to "mixture" and this hardware sets the mixture value to 0.  The Honeycomb stuff sometimes have preset profiles for their levers.   This 'mixture' value in X-Plane, doesn't really mean mixture in the 'recip engine' sense, but rather "fuel flow to the engine", so its applicable to turboprops too.

The second most common culprit is a lack of fuel in the center tank, which feeds the engines.  

For a first troubleshooting test,  I recommend you remove all hardware and try to start the aircraft using only the mouse, making sure you have fuel in the  center tank.  If that works, then we can focus on hardware.

-tkyler

Greetings, I thought the manual indicated that the condition levers were assigned to the ‘props’ command?

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10 hours ago, fleurenf said:

Greetings, I thought the manual indicated that the condition levers were assigned to the ‘props’ command?

The Bravo has 6 Levers. A normal Setup for 2 Engines (Piston or Turboprop) is 2 for Throttle (Black), 2 for Prop (Blue) and 2 for Mixture/Condition (Red). Some Turboprops use all 6 Levers, some not. The MU-2 uses Throttle Levers, assigned to Throttle 3 and 4 Axis, and Prop Levers, assigned to the Prop Axis. The Mixture/Condition Levers are unused and should not assigned to any Function. In Hardware, you can unplug the Levers and use the included Covers to close the Gaps.
If you copy a previous Setup for the MU-2 without deleting the Mixture Setting, it could cause in Problems with non starting Engines. I had this with Rotax Engines too. The confusing Part is, it happens not every Time and not for all Engines.

This is my Bravo Hardware Setup for the MU-2. Black Levers Throttle, Blue Levers Prop. And the Assignments in XPlane. 

 

IMG_20230718_121353.jpg

bravo.png

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15 hours ago, fleurenf said:

Greetings, I thought the manual indicated that the condition levers were assigned to the ‘props’ command?

Sorry, I should have clarified more.  What I meant to say is that sometimes hardware levers are mapped to "mixture" when they should not be at all.  If they are, then 'noisy' hardware, which is super common, can set the fuel flow to 'zero', thereby keeping the engines from starting.  So yes, the condition levers should be assigned to props as documented, but then NO levers should be assigned to mixture.    If hardware ships with configuration files that have pre-assigned the levers to parameters , then they have to be expressely set to none (or not mixture at least).

-tk

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Thx.   Two observations.  1)  I can't see any of your engine gauges, so I don't know whats going on there...I need to see those.  .  and 2)  your trim wheel is "twitching", which suggests you still have hardware  attached to your computer.   Make sure you disconnect your hardware for this test,  and then show the engine instruments in another video so we can have some feedback.  Do not move the condition levers though (ignore my moving them below), leave them where they are.    Show me something like this.

 

 

-tk

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Thx for that.    Next, turn on the "IGNITION CONT" and try that.

but beyond that, a few qustions also?

  • Version of X-Plane?
  • Operating System?
  • Do you have any other plugins installed.  XEconomy,  etc.
  • Are the engine intake covers removed?
  • Are all the fuses pushed in?
  • Are you familiar with the DRE (Data Ref Editor) plugin?    we use it to debug X-Plane datarefs.   You will need this to debug further.

-tk

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