You mean like the J-20?
Chinese Engine Development
- Thread starter jackbh
- Start date
You mean like the J-20?
Quickie
Colonel
There are 101 reasons why some of the (older?) Russian flankers have different AB colour, could be because of older engine type, weather condition etc.
The fact of the matter is the pictures of the Chinese flankers/ J-10A with the AL-31Fs engines always have blue afterburner while those fitted with the WS-10A always has the pinkish orange AB. Remember the flanker engine testbed flying with the AL-31Fx engine and the prototype WS-10A? In this case the 2 engines were using the same type of fuel and flying under the same weather conditions and yet their AB were shown to be of these 2 different colours.
The fact of the matter is the pictures of the Chinese flankers/ J-10A with the AL-31Fs engines always have blue afterburner while those fitted with the WS-10A always has the pinkish orange AB. Remember the flanker engine testbed flying with the AL-31Fx engine and the prototype WS-10A? In this case the 2 engines were using the same type of fuel and flying under the same weather conditions and yet their AB were shown to be of these 2 different colours.
vesicles
Colonel
That is assuming you are burning the same substance.
Different metal ions burn with different colors. For instance, a fuel containing a lot of sodium ions would burn with yellow color (Na+ ion emission wavelength is at ~590nm) while flame containing barium ions would give a green color (Barium ion emission wavelength is at ~554nm). And flame containing a lot of copper ions would be bluish-green. That is, in fact, the basis for flame ionization detector. So without knowing the actual material composition of the fuel, there is no way to conclude that the color difference is caused by temperature.
thunderchief
Senior Member
Logistically , it would be very imprudent for one air force to use different types of fuel for its fighter planes .
Btw , at full afterburner Su-27 has blue flame (2:30) , but little bit earlier you could see yellow tone . We would need to see WS-10 at full afterburner to make conclusions .
[video=youtube;df3vW5HsPlc]https://www.youtube.com/watch?v=df3vW5HsPlc[/video]
vesicles
Colonel
I was responding to No Name's comment on flame color characterization based on chemistry. So theoretically speaking, unless we KNOW for sure they use the same fuel, we don't know the different color is caused by temperature differences or different composition of fuels.
As a matter of fact, it makes more sense to think that the fuels are different. Why? Well, people have been saying that AL-31 engines have been consistently seen as burning with a different color than WS-10. If we assume the color yellow and color blue in the afterburner is caused by temperature difference, that means the two engines are burning consistently at different temperatures that are hundreds if not thousands of degrees apart (yellow flame is close to 1200 oF while blue is close to 3000 oF). That makes no sense at all. Although the two engines are different in power, the difference cannot be that big.
Thus, the only logical explanation is that they burn different fuel.
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I think other things go into the flame colour though, such as the efficiency of the burn, the fuel air mix at various stages, and the trace presence of other substances such as carbon. All these differences could easily be from variations in how each engine operates without drastically affecting flame temperature.
thunderchief
Senior Member
Actually , explanation is very simple . WS-10 was still in testing phase and not fully operational . As such , it didn't go full afterburner and that is why on most of the pictures you see yellow color .
As WS-10 matures , it would be more and more used to full extent of its power . Then you will see similar colors as with AL-31 .
Uhhh...No. I wouldn't count 120 J-11Bs flying around with the WS-10 as "testing phase."
Another factor I forgot to mention is that the colour of the flame will change as it travels through the nozzle, cools, and the flame gets a more even mix with air. The blue colour of the AL-31 is only at present where the igniter is.
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