Engine start

[mrshiljo]

Aircraft Version

Experimental

Build info

...

Describe the bug

Well, as stated, on FBW when starting engines without fuel pumps, nothing hapoens. Thats not correct, if u start engine, starter will run normally untill en g it reaches its max on N2, regardless fuel pump are off. Ok, fuel is not present, eng will not start, it wont get fuel,but it will reach some parameters because starter is working.

Expected behavior

Eng must rotate because starter is working

Steps to reproduce

...

References (optional)

No response

Additional info (optional)

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Discord Username (optional)

No response

[Luz5020]

Last time I tried, the Engine parameters definitely went up as far as they can go on starter only, is the issue that the engine on the model doesn't start to spin?

[Maximilian-Reuter]

To be precise, do you mean there is an issue with the animation of the engine ? Or are you talking about the fact that gravity feeding doesnt work, cause if so then this is a duplicate of #2841

[mrshiljo]

Noooo...i started engine by fault with fuel pumps off, and it didnt start, N2 was stuck below 1...so...when you push fuel pump pushbutton additionaly...engine starts to move. You have it on my video on 16:51

https://www.youtube.com/live/Z3mwSzFor5s?feature=share

So let me repeat...engine will start, and it will even run for a while in rl ecause some of fuel is left in engine system. I did manage to do that while starting once for troubleshooting purposes

Kind regards

pon, 29. svi 2023. 19:27 Chaoz @.***> je napisao:

To be precise, do you mean there is an issue with the animation of the engine ? Or are you talking about the fact that gravity feeding doesnt work, cause if so then this is a duplicate of #2841 https://github.com/flybywiresim/a32nx/issues/2841

— Reply to this email directly, view it on GitHub https://github.com/flybywiresim/a32nx/issues/8050#issuecomment-1567369716, or unsubscribe https://github.com/notifications/unsubscribe-auth/ASFDG76YA6Y5LNUC6XLWZF3XITMADANCNFSM6AAAAAAYS6A3GI . You are receiving this because you authored the thread.Message ID: @.***>

[mrshiljo]

So i dont men manualy starting by starter, i mean nirmal starting automatic without fuel pumps. On FBW engine dont move, dont rotate, N2 is 0, but it should go up to at least 27

pon, 29. svi 2023. 23:17 Shiljo @.***> je napisao:

Noooo...i started engine by fault with fuel pumps off, and it didnt start, N2 was stuck below 1...so...when you push fuel pump pushbutton additionaly...engine starts to move. You have it on my video on 16:51

https://www.youtube.com/live/Z3mwSzFor5s?feature=share

So let me repeat...engine will start, and it will even run for a while in rl ecause some of fuel is left in engine system. I did manage to do that while starting once for troubleshooting purposes

Kind regards

pon, 29. svi 2023. 19:27 Chaoz @.***> je napisao:

To be precise, do you mean there is an issue with the animation of the engine ? Or are you talking about the fact that gravity feeding doesnt work, cause if so then this is a duplicate of #2841 https://github.com/flybywiresim/a32nx/issues/2841

— Reply to this email directly, view it on GitHub https://github.com/flybywiresim/a32nx/issues/8050#issuecomment-1567369716, or unsubscribe https://github.com/notifications/unsubscribe-auth/ASFDG76YA6Y5LNUC6XLWZF3XITMADANCNFSM6AAAAAAYS6A3GI . You are receiving this because you authored the thread.Message ID: @.***>

[Maximilian-Reuter]

I now understand, the issue is that the engines arent even motoring without the fuelpumps.

That is indeed an issue.

EDIT: In my tests the engines do very slowly motor up to 27 %N2 when no fuelpumps are on. Even if you turn them on at that point it starts up very slowly. This is probably an issue with the MSFS Engine model as the FBW engine parameters still depend on the msfs engine parameters

[hotshotp]

I now understand, the issue is that the engines arent even motoring without the fuelpumps.

That is indeed an issue.

EDIT: In my tests the engines do very slowly motor up to 27 %N2 when no fuelpumps are on. Even if you turn them on at that point it starts up very slowly. This is probably an issue with the MSFS Engine model as the FBW engine parameters still depend on the msfs engine parameters

they dont depend on the msfs engine parameters, we have a completely custom engine model outside the sim. i think @Taz5150 would know better about this issue than me.

[tracernz]

they dont depend on the msfs engine parameters

They definitely do to an extent. Basically the FBW code reads the sim parameters, then fudges some numbers and writes back to the sim some parameters.

[Maximilian-Reuter]

I now understand, the issue is that the engines arent even motoring without the fuelpumps. That is indeed an issue. EDIT: In my tests the engines do very slowly motor up to 27 %N2 when no fuelpumps are on. Even if you turn them on at that point it starts up very slowly. This is probably an issue with the MSFS Engine model as the FBW engine parameters still depend on the msfs engine parameters

they dont depend on the msfs engine parameters, we have a completely custom engine model outside the sim. i think @Taz5150 would know better about this issue than me.

the entire system is dependant on the msfs N2 so unless that changes our N2 doesnt either. Hence why it starts up much much slower when it doesnt have the fuel pumps as the MSFS engine model doesnt start without fuelpumps.

[Taz5150]

Sorry I am late to this conversation, but basically you all nailed it. Our model is external mostly to control engine spool times during startup & shutdown, but it does depend on N2. So if using SimVarWatcher you observe N2 rising, then this is an MSFS issue.

Now that being said, I will investigate a little further to understand why is that so.