Indian Air Force: News & Discussions

DumbPilot

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some excellent photos from vayu :)
ps why is su30 after burner is bluish while others are making red flame
View attachment 253542View attachment 253543View attachment 253544View attachment 253545
This might be something to do with how fuel-rich(stage of the afterburner) the engine is currently burning, or deviations due to the camera settings, because there are also images available when Flankers have an orange-flame in the exhaust while others have a blue flame.
 

DumbPilot

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That depends on how much fuel is injected into the engine at the time.
Generally, fuel (blue) < fuel (red).
Check this picture:
View attachment 254062
That depends on how much fuel is injected into the engine at the time.
Generally, fuel (blue) < fuel (red).
Check this picture:
View attachment 254062
Now I am curious to see if any document could be found on these AL-31 engines which explains what the reheat process is. Orange means that not all the fuel was utilized, while blue means that most of it was, so does it mean that the AL-31 engines take time to stabilize?


EDIT: I wonder if this staggered activation of the afterburner is to prevent starvation through fuel feed lines, as fuel flow is exponentially increased towards one engine to sustain afterburner, and then the other?
 

no smoking

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Now I am curious to see if any document could be found on these AL-31 engines which explains what the reheat process is. Orange means that not all the fuel was utilized, while blue means that most of it was, so does it mean that the AL-31 engines take time to stabilize?
No, it means nothing. Different colors mean the engine is in the different working status.

EDIT: I wonder if this staggered activation of the afterburner is to prevent starvation through fuel feed lines, as fuel flow is exponentially increased towards one engine to sustain afterburner, and then the other?
The plane is trying to control the power outputs of the two engines to make different thrusts to turn around.
 

DumbPilot

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No, it means nothing. Different colors mean the engine is in the different working status.
Yes, you are correct. This is due to the different fuel-air ratio in either engine. The one with the blue flame burns hotter than the one with an orange flame.

The plane is trying to control the power outputs of the two engines to make different thrusts to turn around.
That is incorrect - even if the differential thrust had a lot of magnitude, it would have given the plane a yaw moment, which is not the correct way to turn in this case.

The left engine is not burning completely and I am guessing that in the next few frames, both the engines stabilize to one color as they reach their target air/fuel ratio. Incomplete burning also proves why the engines of planes like MiG-29/that use the RD-33 have an orange flame and are extremely smoky, because on the newer Saturn engines, this problem does not exist:

Here's a series of pictures of the IAF Su-30MKI reaching the target air/fuel ratio in either engine:
1716354323285.png


1716354339536.png

(you may notice that the left engine has a brighter flame than the right one)

1716354377265.png
 

MirageBlue

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Ya'll Nibbiars The 220 Desert Tigers.

View attachment 254240
Their current mount is the Su-30MKI..as much as I liked to see the MiG-23BN and MiG-27ML looks wise, they were the least reliable and most unsafe in terms of attrition. Especially the MiG-23BN. Worse than the much maligned MiG-21.

The Su-30MKI in comparison is a generation apart in every way.
 

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