Engine Performance

[humptydumpty]

Hi,

 

I am still going through the documentation for this awesome bird and I have kept "Random Failures ON".

 

Not a good reader so I connect to a freeflight server in MP and try read the gauges like the IAS / Barometric / ADI. Haven't gone further than these instruments.

 

This happens every time I takeoff on AB and after a 10-15 seconds of climb my engine shuts off so I crash land.

 

Help.

 

Thanks.

[Cobra847]

The most obvious issue to me is that you're inadvertently flying at 0G. Is this perhaps the case?

[Nerd1000]

Make sure you've switched on the fuel boost pumps. Also make sure that you aren't pushing negative G, as doing so causes the fuel to go to the tops of the tanks where it can't be pumped to the engine (there is a small feeder tank that allows for short periods of negative G. Once it empties the engine will flame out).

[Elwood]

What about the gmeter? Pitching To level flight maybe cause 0g or even negative. I usually reduce the throttle to level than after burner again to uncage the old beast :-)

[humptydumpty]

The most obvious issue to me is that you're inadvertently flying at 0G. Is this perhaps the case?

 

 

Well it is only during the climb so yes that could be a reason because I am going up almost straight like a rocket :) , but before this even after the rotation when I was not high on the AOA it happened a few times and maybe even during a leveled flight when I pushed to AB

 

 

Do you want me to test it again ? I can do that.

[humptydumpty]

Make sure you've switched on the fuel boost pumps. Also make sure that you aren't pushing negative G, as doing so causes the fuel to go to the tops of the tanks where it can't be pumped to the engine (there is a small feeder tank that allows for short periods of negative G. Once it empties the engine will flame out).

 

All the pumps are ON , I am not sure it happened during a Negative G. It mostly during a climb on AB.

[humptydumpty]

What about the gmeter? Pitching To level flight maybe cause 0g or even negative. I usually reduce the throttle to level than after burner again to uncage the old beast :-)

 

I follow the simple stuff to level out from a climb for the intended altitude 10% of the VVI (but these gauges are complicating :) ) and once I am leveled I let her touch her cruise speed and then reduce the thrust.

 

But I haven't gone to the speeds of her as yet, a lot to read.

[QuiGon]

What about the Nose Cone Switch (RV14)? Is it in the on position? IIRC it can cause problems like this if it's off.

[Nerd1000]

What about the Nose Cone Switch (RV14)? Is it in the on position? IIRC it can cause problems like this if it's off.

 

If that is the issue you should probably be hearing 'Bang' or 'Poof' noises from the engine, accompanied by a sudden loss of RPM.

[humptydumpty]

I will try that climb again when I reach home from work in a couple of hours today and see if it blows.

[mattebubben]

Are you using the Afterburner when these problems occur?

 

And if a yes are you sure you dont have the Emergency afterburner on.

 

Since the Emergency afterburner can increase the chance of a engine failure.

[humptydumpty]

Are you using the Afterburner when these problems occur?

 

And if a yes are you sure you dont have the Emergency afterburner on.

 

Since the Emergency afterburner can increase the chance of a engine failure.

 

I doubt it , but I am going to try it when I get back home.

[OnlyforDCS]

Do post a track file. It's the easiest way to check if you are doing something wrong or not.

[Art-J]

Do post a track file. It's the easiest way to check if you are doing something wrong or not.

 

Ditto. Track with "take off from runway" will be preferable to minimize the unfortunate yet too frequent risk of track corruption.

[humptydumpty]

Yes the track file is a great idea guys. I still think it is the climb that is problem, post the track file in half hour. It will be auto start ( I do know how to manually start it and will on the MP server)

本帖最后于2016年1月19日，由humptydumpty编辑

[grunf]

When I first started to fligh the MiG-21, engine relight was my most used button :D.

 

There are two most frequent causes of the flameout, the first is negative or zero G, either during the inverted flight or by pushing the stick forward. Check your G meter often, when you want to level after a climb or go to dive, don't push the stick, quickly roll to the back and level out. You only have 3 seconds of inverted flight with emergency afterburner, 5 with full AB, 15 seconds with no AB.

 

The second cause is overspeeding - IAS over ~1350 km/h will cause a flameout.

[humptydumpty]

Here is the track file recorded today.

Virtual Aerobatics Test server v1.5.2u1b-20160119-175200.trk

[ESAc_matador]

Most ptobably, negative G. Mig21 is very sensitive at this regard, trying to keep you climbing and making corrections pushing the stick forward abruptly will shut the engine off.

 

Check emergency procedures to restart, there is a switch on the left panel. Put the throttle back and mantain a least 500 IAS somhow (diving).

[BravoYankee4]

When I first started to fligh the MiG-21, engine relight was my most used button :D

 

Amen to that :music_whistling:

[humptydumpty]

I am going for a flight now in the 21 on a VA free flight server and going to try the restart.

 

Yes I think it is the negative or the 0 g as asked by Cobra.

[humptydumpty]

THis one is not for the engine.

 

ATC told me to climb to FL300 so I had a good clean climb to FL200 at around 200kts but suddenly nose started dropping back had no ailerons luckily I realized about the SAU mode and clicked and got the stick back.

 

Great fun.

[humptydumpty]

Can anyone check my track file which i posted earlier. Of course only when one has the time :)

 

Thanks.

本帖最后于2016年1月20日，由humptydumpty编辑

[Vincent90]

Can anyone check my track file which i posted earlier. Of course only when one has the time :)

 

Thanks.

Tried to watch it, but says I need the M2000C Module to watch the track.

 

Could you recreate the problem in Mission Editor or Training?

[humptydumpty]

Tried to watch it, but says I need the M2000C Module to watch the track.

 

Could you recreate the problem in Mission Editor or Training?

 

 

 

Hmm why would it ask for a M2000 I don't have that girl.

 

I got a one more track a different let me try and post that.

Virtual Aerobatics Test server v1.5.2u1b-20160120-132453.trk

[PE_Tigar]

I watched the first one - you've stalled the plane in ~85 degrees climb on full AB. By doing that you've disrupted airflow to the engine and experienced compressor stall. Some airplanes can do that and sustain airflow to the engine, MiG-21 can't.