Engine Failures

[MrSloanes]

So as almost everyone else probably has, I have experienced numerous engine failures in the Mig. Generally down to throwing the old bird around a bit too roughly but lately every time I use the Mig on multiplayer my engines are failing without any reason and I can't understand why.

 

Earlier tonight and the last 2 days or so I'm flying a steady altitude, not banking at all and the engines keep failing. If I'm high enough generally I can recover the engines but they fail again a few minutes later.

 

It seems very inconsistent and I'm not sure if I'm doing something wrong.

 

I've ruled out anything that I may have done or not done when starting her up by joining the virtual aerobatics server where a few of the migs are airborn at the start. They still do the same.

 

Any ideas?

[audax]

I had that problem only when people were shooting at me and my startup isn't very nice and clean.

[MrSloanes]

It's kinda taking the fun out of the mig for me now which is a shame.

[audax]

Do you fly at 100% RPM or even with AB for that long? Afaik they recently modeled engine fatigue and failures.

[MrSloanes]

No i generally stick around 80% the majority of the time.

 

Even the last few days the failures are happening between 5-10 minutes after taking off, surely any failures wouldn't happen in that time period?

[JorgeIII]

As modeled right now engine will only fail if you fly too long with 0 or negative G ( more tan 4 seconds with emergency afterburner, more time with lower regimes) and if max speed is exeded (about 1350 km/h IAS al sea level and mach 2.1 at 10000 m). If you stall the plane the engine might stall too.

Ofcourse the engine will also fail if it get hit or out of fuel.

Edited June 14, 2015 by JorgeIII

[Hadwell]

Engine never fails unless you're using the 2nd afterburner for like 5 minutes streight.

 

When youre doing aggressive combat manuvers, constantly check your G meter, never let it go below 0 gs if you do, the engine starves. Need to flip up the emergency restart switch and keep your speed above 550kph.

[CHRISXTR3M3]

This has only happened to me when as explained in previous post I go under slightly under 0Gs. The engine is gravity fed so if you give it 0 or below 0Gs four about 4 swconds you end up cutting the fuel flow to the engine and it will flare out.

[Sryan]

engine failure can also be induced by being in a to high angle of attack. there's an angle of attack meter on the right-top-centre panel. do you pull it into the yellow or red a lot?

[Hadwell]

how can the engine fail with too high AOA? no... I regularly go into the red on the AOA gauge, pull 11 G turns, etc... never had an engine stall for any other reason than I was going streight up and let my plane stall out, or because I was pushing forwards on my stick.

 

I never use the 2nd afterburner, so I've never had an engine fail on me before...

 

the engine only fails if you burn it out...

 

the engine will starve if you end up 0G or -G, that should never happen if you're always pulling back on the stick, unless you're doing the superman ride thing...

 

failure is irreversable, if the engine stalls because of lack of fuel caused by the -Gs, just right yourself and restart it, the engine didn't fail, just starved...

 

you do need to be careful to turn off the emergency restart when the engine re-ignites, THAT can fail if you leave it on, and then when your engine stalls again, you can't get it restarted.

 

if you overspeed the engine will stall too, mach 2.14 at 10k meters...i believe... you can't overspeed unless you're at an altitude that allows you to go mach 2+ so 10,000m minimum

 

I can't say I've ever oversped my engine at any lower altitudes, would take a great deal of effort, and probably not something that could happen by accident...

 

V said superman ride

Edited June 15, 2015 by Hadwell

[JorgeIII]

Engine never fails unless you're using the 2nd afterburner for like 5 minutes streight.

Glad to know this failure is simulated when abusing emergency AFT, I couldn't do it and thought it wasn't possible, will try to use it for a longer time.

[JorgeIII]

This has only happened to me when as explained in previous post I go under slightly under 0Gs. The engine is gravity fed so if you give it 0 or below 0Gs four about 4 swconds you end up cutting the fuel flow to the engine and it will flare out.

 

You can pull negative G for longer than 10 seconds, just remember to throttle back before you do it.

Just to be safe I prefer to pull 0 or negative G very briefly or just roll and use positive G.

 

AFAIK the internal tank for immediate fuel feed (don't remember the name) has fuel for about 4s with emergency AFT, 7-8 seconds with normal AFT and over 15 seconds without AFT. This tank stops getting fuel at 0 or negative G.

[JorgeIII]

 

if you overspeed the engine will stall too, mach 2.14 at 10k meters...i believe... you can't overspeed unless you're at an altitude that allows you to go mach 2+ so 10,000m minimum

 

I can't say I've ever oversped my engine at any lower altitudes, would take a great deal of effort, and probably not something that could happen by accident...

 

Really Hadwell? My experience is the opposite. After the scripted speed limit was removed, the Mig-21, with any regime of AFT on and at level flight, will always speed up until overspeeding and engine failure, at any altitude. Unless its very heavy, with 800L ventral tanks, bombs, etc.

 

Just fly level with AFT ON in a clean plane or only carrying missiles and see what happens.

 

Max speed with AFT at level flight in current bild is not reached by a relation between engine power vs drag but by engine failure.

 

To prevent overspending I have to continuously turn ON and OFF AFT near max speed or manually limit the nose cone to a value of 3.7 to 4.

 

Reported bug and partially fixed:

http://forums.eagle.ru/showthread.php?t=136200

Edited June 15, 2015 by JorgeIII

[Art-J]

^ Nah, maintaining max rated speed of Ma 2.05 for a couple of minutes is possible when throttling back a little (as discussed in the thread linked by You) so that EGT is about 680 degrees. I admit it's balancing on a very thin line, however and it requires using all of pilot's attention. I wouldn't mind seeing this aspect of FM fine-tuned somewhat.

 

About emergency afterburner - I'm not sure if its limitations (3 minutes continuous as mentioned in manual) work correctly in current version of the module. A couple of days ago I tried to do some low level flying with it turned on all the time, to break the engine on purpose. My experiment failed though, because after burning almost all the fuel load, the engine kept on working fine. I didn't measure time, but it certainly was 3 minutes multiplied by many many times ;).

[Hadwell]

^ Nah, maintaining max rated speed of Ma 2.05 for a couple of minutes is possible when throttling back a little (as discussed in the thread linked by You) so that EGT is about 680 degrees. I admit it's balancing on a very thin line, however and it requires using all of pilot's attention. I wouldn't mind seeing this aspect of FM fine-tuned somewhat.

 

About emergency afterburner - I'm not sure if its limitations (3 minutes continuous as mentioned in manual) work correctly in current version of the module. A couple of days ago I tried to do some low level flying with it turned on all the time, to break the engine on purpose. My experiment failed though, because after burning almost all the fuel load, the engine kept on working fine. I didn't measure time, but it certainly was 3 minutes multiplied by many many times ;).

 

no you can get it up to and hold it at mach 2.1 at 11500m just tap the airbrakes on and off, may not be as efficiant as fiddling around with the throttle, but its WAAAY more precise, and no giant puffs of smoke out the back...

 

 

and yeah you can't really stall the engine at low altitude from overspeed... you just can't get the plane fast enough, without doing a powerdive from 12,000m or something anyway...

 

and maybe engine failure isn't simulated with the 2nd afterburner... i've never tried to be honest...

 

try running the emergency afterburner for a full tank of fuel, land it, re-arm, and take off and see if the engine still produces the same amount of power? maybe 3 minutes is max before it starts degrading the engine, but not destroys it completely.... if you then let the engine cool, and then try to re-heat it... maybe?

Edited June 15, 2015 by Hadwell

[JorgeIII]

Yes, indeed excesive emergency AFT use dosent seems to degrade the engine.

 

 

and yeah you can't really stall the engine at low altitude from overspeed... you just can't get the plane fast enough, without doing a powerdive from 12,000m or something anyway...

 

 

No Hadwell, at ANY altitude the mig will overspeed until engine failure if flown with AFT and not to much payload (eg. without external fuel tank). Just tried again right now in case I didnt notice an update in flight model. Try it yourself, open the mission "free flight" from quick missions, turn your nose away from mountanis, turn recovery mode for a level flight and turn on AFT and see what happens. I just ovespeed and had an engine failure after 2.5 minutes of afterburner (about 1370 km/h IAS, no emergency AFT use). No need to dive or fancy manuvers, just level flight and AFT ON and it will easily overspeed until engine failure.

Thanks for the tip of airbrake at high altitud.

Edited June 16, 2015 by JorgeIII