hmjets

BEAUTIFUL FLYING DISPLAY AND NICE AIRCRAFT SCHEME,AFTERBURNER PROBLEMS??

https://www.youtube.com/watch?v=8p57R1Isuz4

chrigui

yes A/B problem ... there is video showing A/B blow and following landing

FalconWings

My Feedback: (57)

That's no A/B blow.....those are flares followed by landing. That's how they finish their demo routine.

Saw the whole video and did not see any afterburner issues at all.....performing flawlessly.

mauryr

https://www.youtube.com/watch?v=x51UYlumFS8

The afterburner flame front is messed up the whole flight... definitely not flawless..

FalconWings

My Feedback: (57)

That's a different video.

There is really no physical description as to how an afterburner flame should look like. It could certainly look different at different day light conditions. Engine was running fine, otherwise he would not be able to maneuver like that.

What you see there is a classical scenario of running into your own wake, causing inlet distortion and a short phased compressor stall. It is a lot more dramatic at full power, as he was. The ball of fire you see is simply raw fuel.The compressor stall activates the warning light, so the pilot probably aborted because of that.

mauryr

I am no afterburner expert, but it seems to me that this is a 'proper' afterburner flame (seen at night for maximum visibility):


Notice how the flame starts wide and full and tapers evenly

Now this is the afterburner from the first video in the OP (not the one I posted with the unburnt fuel explosion):


Notice how the flame is not full at the nozzle (maybe because of light? I don't know), but how it becomes wider as it's further away from the nozzle... It also looks much longer than the one in the first picture, considering night vs daylight conditions.
My guess is that this afterburner was already faulty in the first video and was not able to burn all the injected fuel. The extra fuel only burns at the very end of the flame.
The explosion seen in the second video looks to me like a puddle of fuel shot out by the exhaust and ignited outside the engine. Doesn't look like a compressor stall at all to me.

Anybody with real knowledge of this stuff care to enlighten us?
Thanks

hmjets

http://www.f-16.net/forum/viewtopic....352199#p352199

mauryr

When a manifold becomes 'coked' it will affect it's ability to equally distribute the fuel around the circumference of the manifold. This will create high fuel-flow areas, and low fuel-flow areas within the augmentor. These fuel flow imbalances will then cause hot/cold streaks, or overly rich/lean areas of combustion.

Here's our answer!

FalconWings

My Feedback: (57)

"What I see in the photos of this post would lead me to believe the augmentor spray manifolds are 'coked' but without augmentor anomaly, (MFL/PFL or pilot reported) there is no reason to troubleshoot the streaking. Then again, they may have already been inspected and found to be acceptable according to installed engine (aka flight line) limits"

Again....there are no afterburner flame visual standards. If the engine runs fine, it runs fine. The ball of fire you saw was not afterburner related, you clearly see the short phased compressor puff. He landed because of that, not because the engine had any malfunction.

rgburrill

Finally is video that really is spectacular instead of the ho-hum videos so many post here and others call the spectacular fights.