Never stop engines from MAX power :)

[Yo-Yo]

If you have this bad habit it's the time to get rid of it... or you will have problems... :)

I mean any type of flame-out.

[WarriorX]

Yo-Yo, are you referring to the behavior of engine flame out due to rapidly pulling the throttles back to idle?

 

I used to suffer from it when in a dive and thought I could chop the throttles and keep my dive speed down. After 5 or so flame out's and some successful gliding engine restarts, I ended that habit.

 

Now I try to mange my energy going into the dive, but am now more comfortable and more appreciative of the higher energy when I come off the dive.

[Yo-Yo]

Yo-Yo, are you referring to the behavior of engine flame out due to rapidly pulling the throttles back to idle?

 

I used to suffer from it when in a dive and thought I could chop the throttles and keep my dive speed down. After 5 or so flame out's and some successful gliding engine restarts, I ended that habit.

 

Now I try to mange my energy going into the dive, but am now more comfortable and more appreciative of the higher energy when I come off the dive.

 

The engines stop at diving? If so I must check. How can I reproduce it? Weather, altitude, IAS?

 

I think they mustn't.

 

But now I meant something new that is coming soon... :)

[MTFDarkEagle]

But now I meant something new that is coming soon... :)

Woo woo wooow Hang on there! New feature?? :D

[luckybob9]

I believe he is saying that in a future patch, keeping the engines at max power will somehow damage or flame them out. So if you are in the habit of always flying with max power on....time to change that :)

[ZMEY-HS-]

Core lock?

[BlueRidgeDx]

Core lock only occurs after a flameout at high power, due to rapid and uneven cooling of internal rotating parts. Even then, is a pretty rare phenomenon that GE maintains doesn't exist.

[SonofEil]

Hmm, curious. I remember the hog pilots I worked with years ago said that they kept the engines at max around 75 percent of the time. Maybe I remember that incorrectly, but I do know that we'd also do extended max power runs in test cell as a matter of routine.

I guess we'll find out soon enough. Very cryptic.

Thanks Yo-Yo!

[Snoopy]

Hmm, curious. I remember the hog pilots I worked with years ago said that they kept the engines at max around 75 percent of the time. Maybe I remember that incorrectly, but I do know that we'd also do extended max power runs in test cell as a matter of routine.

I guess we'll find out soon enough. Very cryptic.

Thanks Yo-Yo!

 

Another question I'll ask our pilots when I see them...

[Dimebag1]

Engine overheat? Or maybe oil overpressure? That's if there even is an engine oil indication, don't remember one.

[PhiXX]

I think maintaining max power is not the problem. Shutting the engine down quickly from max power seems to be a bad as they're probably running very hot then, followed by rapid, uneven cooling...

 

just guessing :thumbup:

[MrYenko]

Core lock only occurs after a flameout at high power, due to rapid and uneven cooling of internal rotating parts. Even then, is a pretty rare phenomenon that GE maintains doesn't exist.

 

Mmmhmmm... Look the other way. Nothing to see here. :music_whistling:

 

:angry:

[mtuckner]

Yeah, I interpreted it as going to idle from max power will cause a problem, and not keeping it at max power.

[Kenan]

I think maintaining max power is not the problem. Shutting the engine down quickly from max power seems to be a bad as they're probably running very hot then, followed by rapid, uneven cooling...

 

just guessing :thumbup:

 

 

I believe this is what Yo-Yo refered to. Makes sense.

[SY_KO]

I wonder if what Yo Yo is referring to is a Hot Shutdown. This is something seen in turbos when the engine has been running at max torque for a long period, usually exh temps can hit near 800c for diesel, and then the engine is just shut down. Heat then soaks through the turbo heating the bearings and the shaft which can then seize due to essentially the parts welding together. Thats the worst case situation but this also leads to oil coking on the components accellerating wear leading to bearing failure. In the turbo world you only have to do a few of these hot shutdowns to wreck the turbo.

 

Now a turbo isn't exactly a turbofan engine but the principle is the with a comp connected to turn via a common shaft with a combustion system between the two. I guess with a jet engine the issue could be scaled up as they tend to have more than one common shaft.

Edited March 26, 2011 by SY_KO

[aaron886]

This is something seen in turbos when the engine has been running at max torque for a long period, usually exh temps can hit near 800c for diesel, and then the engine is just shut down. Heat then soaks through the turbo heating the bearings and the shaft which can then seize due to essentially the parts welding together.

 

 

That (coking?) would be best synonymous with core lock in a turbine.

[SY_KO]

That (coking?) would be best synonymous with core lock in a turbine.

 

We would just say a seized rotor for core lock. I may try introduce core lock as a term in our business though as we call a turbo without end housings a turbo core.

 

Coking is the term used to describe the oil that has carbonised on the components due to the high temps. It looks like black powder but is nigh on impossible to get off of the parts when formed and acts as an abrasive. once it's there it's there for good and only gets worse :D

 

Moral of the story... Don't do hot shutdowns with turbos or turbofan engines, especially those in the next DCS A-10C patch (or which ever the feature it is included in :D )

Edited March 26, 2011 by SY_KO

[Yo-Yo]

OK, some of you are right. I am not sure, it will be in the next patch but it will be for sure.

All in all my advise is to train proper engine maintanance right now :)

 

The way you will fight with locked engine will not be bore...

Edited March 26, 2011 by Yo-Yo

[Napa]

Any chance to add proper maintenance, procedures and handling of the TF34-GE-100A in the manual?

 

P.S. Also a bit offtopic (nothing to do with DCS, its about the real A-10C), do you guys have any clues weather the A-10C fleet will upgrade their engines to the TF34-GE-100B?

[sobek]

Now a turbo isn't exactly a turbofan engine but the principle is the with a comp connected to turn via a common shaft with a combustion system between the two. I guess with a jet engine the issue could be scaled up as they tend to have more than one common shaft.

 

The main difference is that in a turbocharger, the oil pump isn't driven by the turbine shaft, so when you kill the engine, there is no oil pressure, which is kind of a problem if your bearings are hydrodynamic and rely on a steady flow of oil to not have a failure.

 

In the turbine engine, you at least have lubrication until the turbine runs down, on the other hand, a turbine is much larger and stresses due to uneven expansion or contraction are probably far worse.

Edited March 26, 2011 by sobek

[fragged]

The line on the landing checks hit my eye when I first read the manual.

 

After 5 minutes at IDLE, set left throttle to OFF and confirm core RPM reaches 5% and ITT is below 200c

 

I'm guessing this is related.

[robmlufc]

Most jets I've worked on will sit at idle until certain temp is reached, its like cooling your Turbo on a car before shutting down, otherwise you will get tons of heat soak. Prop planes often give it a quick blast before shut down to get some cool air down the engine (grove tutor and tucano anyway).

[RogueRunner]

You need to manually turn the props through a few times after shutdown on the Jetstream 41 to prevent shaft bowing.

[Snoopy]

Talked to one of our pilots and this is what he said about Max power:

 

"Flying at max power is not uncommon, but most guys I flew with flew at something under max power so the wingman had some room to keep up. You never plan to fly at max because there is no way to catch up if you get behind.

 

There used to be restrictions on the amount of time we could fly above 810C ITT, but that went away with the improved hot section (HSLI) and TEMS. I used fan speeds as a way to brief power settings. 80% was 300 KTAS. Fuel flow also works to set an indicated airspeed: 1200lb/hr=200 KIAS, 1500lb/hr=230 KIAS, 1750lb/hr=250 KIAS, 2000lb/hr=270 KIAS and 2500lb/hr=300 KIAS. Those numbers are per engine fuel flows. ITT settings and RPM settings can be used, but they differ greatly from engine to engine and jet to jet, based on the engine tuning. "

[MrYenko]

Most jets I've worked on will sit at idle until certain temp is reached, its like cooling your Turbo on a car before shutting down, otherwise you will get tons of heat soak. Prop planes often give it a quick blast before shut down to get some cool air down the engine (grove tutor and tucano anyway).

 

When people do this with piston engines, its actually the opposite effect they are looking for. They are getting the chambers good and hot, to burn off any deposits on the spark plug electrodes, so next time you go to start the engine, the plugs aren't grounded out with fuel deposits. Any spark plug running high-octane and/or leaded fuel will exhibit fouling when operated at extremely low combustion temps and pressures, such as during extended idle. :thumbup:

 

As an aside, in a car, you can run a hotter heat range plug to try and butcher your way around this, however, the higher heat range could cause pre-ignition due to the plug retaining more heat, and causing a hotspot in the chamber during the compression stroke.