Getting frequent engine flameouts in steep climbs

[dok_rp]

Hello guys,

 

I am getting frequent engine flameouts whenever I climb at steep angles and high speeds.

 

For example, in a climb @45º and 1300km/h from sea level, I'll almost always get a flameout at around 8km of altitude.

 

Another extremely strange thing is that I tried to avoid the flameout by immediately pushing forward on the stick to descend and generated over -2G. The pilot blacked out and never returned. It was a straight plunge from 8km to the ground.

 

Could the pilot have died from the negative G's?

 

Is the engine of the Su-27 so fantastically prone to flameouts at steep climbs? I tested in the F-15 and could not even come close to a flamout under the same conditions.

 

Thanks for any feedback. :)

[Weta43]

It will flameout under negative G quite quickly with the reheat on. Pushing the nose forward will only prolong/agravate the issue.

 

Your pilot's not dead - just suffered a massive stroke...

[dok_rp]

It will flameout under negative G quite quickly with the reheat on. Pushing the nose forward will only prolong/agravate the issue.

 

Your pilot's not dead - just suffered a massive stroke...

 

Just tested again forcing the negative G in the climb with the AB on and indeed it does flameout within a second.

 

Thank you so much for the assistance.

 

I loved the "stroke" explanation. hahahaha... Thanks. Gotta stay away from negative G's with that bird. Dangerous combination. :thumbup:

 

:pilotfly:

[DarkFire]

As long as g>=1 the engines will receive fuel and continue to work. The aircraft has what I think I remember correctly as being described as a cache tank which pressure-feeds the engines in situations where g<1. The problem is that the cache tank on the Su-27 is very small so if you're inverted and therefore at -1g the engines will use up the contents of the cache tank quickly, after which they'll flame out.

 

To give you an idea, at maximum thrust (full afterburner) at low altitude (~<1000m) the contents of the cache tank will be used up in less than 5 seconds. I think the maximum duration is about 15 seconds at high altitude and low thrust.

 

This is why Su-27 pilots are instructed to always roll and pull inverted rather than simply pushing the stick forwards and nosing over.

 

If your engines do start to flame out, if you can return to g>0 VERY quickly (less than 1 second) they usually spool up again. If not, game over.