need evidence Engine Startup Sounds Don't Align With Reality

[dresoccer4]

When firing up engine 1 by holding start switch left, the sounds begin of the turbine spooling up, however if you just let go of the switch, then engine immediatly spools down, but the sounds continue to spool up as if the engine is continuing the start. 

[Lord Vader]

Hello @dresoccer4

Even though this could be an issue where the sound continues to play regardless of player action, we would like to see some evidence of what you say is "reality". Is there any unclassified and publicly available information that states that when this switch is turned off it will interrupt the starter spooling? If you have this info, please share it with @BIGNEWYvia private message.

You see, the CH-47F includes a FADEC system that controls all functions of the engines, including the automatic engine start procedures. Therefore, if you action the starter, FADEC takes over and continues with the procedure. In fact, there's no reason to manually switch the starters off, since the automation will do so after NG exceeds 48%. If you are simulating the procedure to abort an engine start, you should actually move the condition levers to STOP. 

Thank you for understanding. We're trying to produce realistic procedures.

[jonsky7]

51 minutes ago, Lord Vader said:

Hello @dresoccer4

Even though this could be an issue where the sound continues to play regardless of player action, we would like to see some evidence of what you say is "reality". Is there any unclassified and publicly available information that states that when this switch is turned off it will interrupt the starter spooling? If you have this info, please share it with @BIGNEWYvia private message.

You see, the CH-47F includes a FADEC system that controls all functions of the engines, including the automatic engine start procedures. Therefore, if you action the starter, FADEC takes over and continues with the procedure. In fact, there's no reason to manually switch the starters off, since the automation will do so after NG exceeds 48%. If you are simulating the procedure to abort an engine start, you should actually move the condition levers to STOP. 

Thank you for understanding. We're trying to produce realistic procedures.

I've never worked on a CH-47F, but I am a aircraft maintenance engineer (767, 747, 777, 787, A350, A380), on every aircraft I've ever worked on, putting the start switch to off will absolutely switch the starter off, both for the safety of personnel and aircraft.
edit: And although the switch may be connected to the aircraft systems, they are also directly wired to the engine!

Now the FADEC might do some things automatically, like continue to turn the engine after a failed start (dry cycle to evaporate unburnt fuel), and even do another start attempt after the failed one, but it will NEVER EVER EVER continue or initiate turning an engine with the start switch set to off. Even doing any sort of test via the maintenance terminal will require the start switch to be set to start/run manually before the engine will turn.

Regards
Jon

Edited November 21, 2024 by jonsky7

[dahui]

6 minutes ago, jonsky7 said:

I've never worked on a CH-47F, but I am a aircraft maintenance engineer (767, 747, 777, 787, A350, A380), on every aircraft I've ever worked on, putting the start switch to off will absolutely switch the starter off, both for the safety of personnel and aircraft.

Now the FADEC might do some things automatically, like continue to turn the engine after a failed start (dry cycle to evaporate unburnt fuel), and even do another start attempt after the failed one, but it will NEVER EVER EVER turn an engine with the start switch set to off. Even doing any sort of test via the maintenance terminal will require the start switch to be set to start/run manually before the engine will turn.

Regards
Jon

i confirm this (Licenced Helo Engineer)

The FADEC will stop the Fuel Flow once you switched to the Starter to the OFF Position and prevents it from overheating (ie HotStart) Only if the Engine Start is completed, the "Starter Stop" is useless.

Regardless of the the Reality simulated wrong, if a Value goes down on the Engine Page, the Sound belonging to the value should also go down

Edited November 21, 2024 by dahui

[cw4ogden]

If I recall correctly, the start switch needed to be held to a certain value around 8 to 10% N1 to initiate start sequence.  We therefore held the switch to around 12% N1 for fudge factor, but as best as memory serves me, if you released the switch too early the start would not initiate.

[jonsky7]

10 minutes ago, cw4ogden said:

If I recall correctly, the start switch needed to be held to a certain value around 8 to 10% N1 to initiate start sequence.  We therefore held the switch to around 12% N1 for fudge factor, but as best as memory serves me, if you released the switch too early the start would not initiate.

Hmm yeah, I've jumped the gun a bit there  haven't I?

On the airliner's, the start switch is magnetically latched to on (Boeing), until the engine reaches self-sustaining when it releases, but you can force it to the off position to stop the start right up until the self-sustaining speed, when as dahui points out, the switch is useless and the fuel cut-off switch is used to stop the engine instead.

Edited November 21, 2024 by jonsky7

[Lord Vader]

Thank you all for explaining your background. Unfortunately, we still need evidence that once the FADEC procedure starts if the switch is (somehow) manually set to off, the engines will stop spooling. Again, this is not contemplated in the available reference. We will certainly change this behaviour if it is indeed wrong.
I am not trying to be difficult or override your professional experience, we just need solid evidence this is not behaving as expected on the real CH-47F before we present this to the team. 

[jonsky7]

1 hour ago, Lord Vader said:

Thank you all for explaining your background. Unfortunately, we still need evidence that once the FADEC procedure starts if the switch is (somehow) manually set to off, the engines will stop spooling. Again, this is not contemplated in the available reference. We will certainly change this behaviour if it is indeed wrong.
I am not trying to be difficult or override your professional experience, we just need solid evidence this is not behaving as expected on the real CH-47F before we present this to the team. 

Well, I guess I maybe should have actually gone into the game and tested it before chiming in, I can't really reproduce OPs fault.

What I would say is a possible bug is the start point of the spool up noise. The engine makes NO sound until it reaches about 18% NG, either in internal or external views, then the spool up sound starts.

I understand that the engine starters are hydraulic motors so maybe quite quiet, but the T55-GA-714A engine output speed is 15,000rpm, so 18% is about 3000rpm, and that's the output shaft, N2 would already be spinning far faster than that to produce enough gas to turn N1 at 18%.
I would have thought it would make some noise well before getting to that speed?

Edited November 21, 2024 by jonsky7

[BIGNEWY]

A reminder to all, please do not post real world manuals here on the forum, if you feel the information is relevant please DM me, but we can only use approved for public documentation. 

thank you 

[cw4ogden]

5 hours ago, BIGNEWY said:

A reminder to all, please do not post real world manuals here on the forum, if you feel the information is relevant please DM me, but we can only use approved for public documentation. 

thank you 

Unless I'm missing something the D model operator's manual is approved for public release, but will refrain from doing so if it's frowned upon.

[Rogue Trooper]

N1 12% is engines hot to trot automatic spool up and only fuel cut off will stop the spool!