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Is APU required to start when ground power is attached?


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Probably asked before, but what is the importance of ground power if you need APU to start engines?

 

And what do momentary motor / ignition switches do?


Edited by WildBillKelsoe

AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

 

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.

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Probably asked before, but what is the importance of ground power if you need APU to start engines?

 

And what do momentary motor / ignition switches do?

You need the APU running because engines are started with bleed air from it.

The switches you mentioned are for in-flight engine restart for upper (IGN)position and downward(motor) is used to remove fuel from engine after failed start to prevent engine overheat when restarting the engine.Middle position is for normal operation.

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Ground power gives you electricity only. To turn the engines pressurized air is used, that's what the APU delivers.

 

The motor switch allows you to turn the engines without doing the startup, i.e. without ignition and fuel injection. The ignition switch is for in-flight windmill restarts (force ignition on when sufficient RPM is reached).

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Just to add to what _Randolph93 and Luzifer posted, you do not need ground power to start the A-10. Additionally, in RL, maintenance crews may use ground power to perform certain operational checks and other maintenance.

To whom it may concern,

I am an idiot, unfortunately for the world, I have a internet connection and a fondness for beer....apologies for that.

Thank you for you patience.

 

 

Many people don't want the truth, they want constant reassurance that whatever misconception/fallacies they believe in are true..

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In RL you have a huffer you can use to start the engines.. it's basically an APU on wheels to save the service life of the aircraft APU. We used to put small critters we'd find in liquid oxygen, then throw them in the exhaust on the top of the huffer. The over oxygenated frozen critter would become a very bright ball of flame flying far up into the air.. that would hopefully burn out before it came back down.

 

Question: Is it possible to do a cross bleed start from engine 1 to engine 2? Does anyone have a procedure?

It's a good thing that this is Early Access and we've all volunteered to help test and enhance this work in progress... despite the frustrations inherent in the task with even the simplest of software... otherwise people might not understand that this incredibly complex unfinished module is unfinished. /light-hearted sarcasm

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Again, I do not think A-10 need the ground bleed air nether to start.

 

On the cross bleed start, I have not done it for a while but it was possible in the past

 

Edit:

I just tried and yes, you can start either engine with the other without the APU being on.


Edited by mvsgas

To whom it may concern,

I am an idiot, unfortunately for the world, I have a internet connection and a fondness for beer....apologies for that.

Thank you for you patience.

 

 

Many people don't want the truth, they want constant reassurance that whatever misconception/fallacies they believe in are true..

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Probably asked before, but what is the importance of ground power if you need APU to start engines?

 

And what do momentary motor / ignition switches do?

 

As stated above, you need APU to start the engines. The thing I found ground power useful for were repairs on the ground - since you have to turn off your engines for that, it is good to connect ground power not to have to do the nav realignment etc.

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As stated above, you need APU to start the engines. The thing I found ground power useful for were repairs on the ground - since you have to turn off your engines for that, it is good to connect ground power not to have to do the nav realignment etc.

 

You don't have to do that either. Real world ops we shut #1 down first. Once the fuel details we start the APU then shot down #2.

 

As said above we don't use external power and air to start up. Normal ops is if the APU won't start we ground abort that aircraft and step to a spare. I'm sure it's been done occasionally but in 20 years I have never seen an A-10 stared with a -60 and hobart.

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Thanks guys

AWAITING ED NEW DAMAGE MODEL IMPLEMENTATION FOR WW2 BIRDS

 

Fat T is above, thin T is below. Long T is faster, Short T is slower. Open triangle is AWACS, closed triangle is your own sensors. Double dash is friendly, Single dash is enemy. Circle is friendly. Strobe is jammer. Strobe to dash is under 35 km. HDD is 7 times range key. Radar to 160 km, IRST to 10 km. Stay low, but never slow.

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Good info Snoopy, thanks! We often used a huffer in the Navy for engine start.. maybe AF has better APUs :)

 

mvsgas, is there a crossbleed switch, or can you just; APU start > Engine1 > APU shutdown > Engine2(auto crossbleed from Engine1)?

It's a good thing that this is Early Access and we've all volunteered to help test and enhance this work in progress... despite the frustrations inherent in the task with even the simplest of software... otherwise people might not understand that this incredibly complex unfinished module is unfinished. /light-hearted sarcasm

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  • 2 weeks later...

mvsgas, could you elaborate on how you did a cross bleed start of engine2 off of engine1 instead of the APU? Didn't work for me.

It's a good thing that this is Early Access and we've all volunteered to help test and enhance this work in progress... despite the frustrations inherent in the task with even the simplest of software... otherwise people might not understand that this incredibly complex unfinished module is unfinished. /light-hearted sarcasm

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Good info Snoopy, thanks! We often used a huffer in the Navy for engine start.. maybe AF has better APUs :)

 

mvsgas, is there a crossbleed switch, or can you just; APU start > Engine1 > APU shutdown > Engine2(auto crossbleed from Engine1)?

 

mvsgas, could you elaborate on how you did a cross bleed start of engine2 off of engine1 instead of the APU? Didn't work for me.

 

Run up the good engine to 85% and place the other engine's throttle over the hump.


Edited by Snoopy
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Thanks Snoopy, that explains it.. I tried to motor the engine up then ignite instead of just pushing the hump.

It's a good thing that this is Early Access and we've all volunteered to help test and enhance this work in progress... despite the frustrations inherent in the task with even the simplest of software... otherwise people might not understand that this incredibly complex unfinished module is unfinished. /light-hearted sarcasm

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