Engine 1 turning on the Ground (windmilling?)

[Chrjs 61]

Hi,during some of my many flights in NGX over the last few months i encountered something strange, which i now want to trace down whether it is some "fault" on my computer side, pilot error, bug or the way it is supposed to work.Parked at the gate, engines shut down, Engine 1 sometimes starts to rotate and i can hear on the outside some "beating" noise (not like the spooling up sound or other regular starting noises). Engine Start Switches are in the Off position and the Engine Fuel Switches in the Cutoff position. Engine Indications on the EICAS show Engine 1 N2 at around 24-25% and N1 around 1%. It seems not to affect Engine start up, except that i do not see N2 rise until the value of around 24-25%. Is this supposed to be the windmilling effect in a windy environment? it does however only happen with Engine 1 as far as I know!Some Addons I use:ASEFS2Crew (but happened also before)REX2ODPFEFSUIPC (registered)Thurstmaster Warthog ThrottleSaitek Pro Flight YokeSaitek Rudder PeddalsAnybody else experiencing this strange behavior? No fun-breaker for me but i would like to know what is going on!

[GraemeBr 0]

I have heard this too not only on the NGX but also in RW. I think it might be an addition in SP1C as I haven't noticed it until recently.I believe it is the fans turning freely due to the wind while parked. I seem to recall seeing a mention of this in one of the manuals as a consideration for engine start when this occurs.

[Chrjs 61]

I have heard this too not only on the NGX but also in RW. I think it might be an addition in SP1C as I haven't noticed it until recently.I believe it is the fans turning freely due to the wind while parked. I seem to recall seeing a mention of this in one of the manuals as a consideration for engine start when this occurs.

I thought about that too, but it seems as only Engine 1 is turning and never engine 2.... :huh:Haven't tried to actually start the engine w/o using APU bleed air, but it might work as N2 is at the appropriate 25%.

[kevinh 409]

24% N2 would be high for windmilling in flight. On the ground you might see 2-3% N1 in a strong wind, but unlikely to see any N2 rotation. Also the fan would windmill before the core, so 1% N1 and 24% N2 is not going to happen in the real world unless the core is driven by the starter. I suspect what you are seeing is the PMDG engine simulation not commmunicating correctly with FSX and hanging at a high N2 value during shutdown (or perhaps getting a false starter torque even though the starter appears to be off).I've seen it a couple of times, but restarting the sim has sorted it out. Both FSX and the NGX are complex software and if one part stops working odd things may happen.

[davidz 26]

Hmm... windmilling shouldn't get your N2 to 25%!

[Jack_C 1]

Yeah, 25% is way too high. I will find out if its a fsx retriction. But to see one engine spinning andthe other not turn is very common on the real thing. JackColwill

[Chrjs 61]

Yes 25% N2 seems really too high. BUt maybe you could first tell me whether you see this phenomenon in the NGX too? Maybe it is just a problem on my side...

[davierosoft 13]

The reason, on the RW plane of having one N1 spinning, while the other is still stopped is the wind direction, if you have frontal or tail wind, in the exact direction of the aircraft heading, both engines will spin at the same speed, but, if wind is oriented differently, the fuselage and other ground obstacle will reduce the effects on the "covered" engine.25% of either N1 or N2 will mean a typhoon able to let the aircraft to take off with chocks installed.Here it seems that something is wrong.I've not tried with sp1c, will try asap, but in the previous versions, the windmilling was badly simulated on ground.To let the engine moves with winds, you must at least spool the engine with ground starter, and then it will work also with winds, if you don't let to rotate the engine, it will never spool. This as far as I remember was valid for both engines.

[davierosoft 13]

Just finished testing the windmilling...Nothing changed with SP1cI tried with winds of about 130-150kts, head wind.The fan on both engine has not moved untill I gave just one or 2 seconds of starter spool up. Then, the fan blades started to turn and remained in spooling by the wind.Now, testing it, I found another issue related to the APU GEN auto transfer to the IDGs at take off.The finding was purely accidental, moving the elevator the aircraft took off with only APU power, then, at lift off the automatic transfer disengaged APU generators... With engines in windmilling the result was a complete AC power source loss (except for stby).This is not possible, a required point to act the automatic transfer at lift off is to have IDGs working and RTL (ready to load).Not a big issue but present.

[3-2-1-Now 126]

The engines not windmilling until you start them turning is an FSX bug, but seeing 25% N2 is definitely something else!Best regards,Robin.

[davierosoft 13]

25% of N2 is something related to the starter that is working. So, it is either locked in open position (bleed applied) or the starter knob is in GRD position.Anyway, if the starter valve is open, a message is displayed on the EICAS.I think that the most probable cause in the NGX is an old panel state.PS: I was not aware about the windmilling limit of FSX, I was remembering about another aircraft able to windmil on ground (maybe the lds 767, but on fs2004).

[Chrjs 61]

The engines not windmilling until you start them turning is an FSX bug, but seeing 25% N2 is definitely something else!

25% of N2 is something related to the starter that is working. So, it is either locked in open position (bleed applied) or the starter knob is in GRD position.

Thanks for the replies. that's what i think as well. Start switch is not in ground or anything else. i alsways start with the default c&d. i will keep on investigating. as i said, it does not really affect the "experience"....

[3-2-1-Now 126]

I was remembering about another aircraft able to windmil on ground (maybe the lds 767, but on fs2004).

I think so too.Best regards,Robin.