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#72
12-10-2010, 06:07 PM
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Flame colour has nothing to do with the angle you view it from or the length of the exhaust pipe, it is nothing to do with temperature either. It simply shows how efficiently the fuel is burning.
If the combustion is burning all the carbon you get blue flames and no smoke. If there's carbon coming out in the exhaust gases then you'll get yellow-er/smoky-er flame. This is chemistry not opinion. |
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#74
12-10-2010, 06:24 PM
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Seeing all the vids of merlins and DBs I'd say blueish like many before me.
The color of flames indicate temperature and as temperature increases flames turn more transparent (the hottest temperatures are nearly invisible as I remember from chemistry class) but hey, I'm not an expert at that I think the flames should be more transparent (in case when you'd use blueish flames). They also should illuminate the fuselage just slightly... just my opinion as a draughtsman, from what I've seen in the vids posted. Anyway, nice feature... Edit: maybe winny is right about that, efficiency rather than temperature but still Last edited by McHilt; 12-10-2010 at 06:34 PM. |
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#75
12-10-2010, 06:44 PM
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Quote:
Color is related to the temperature of gases produced during combustion: the hotter, the whiter; the colder, the redder. Blue indicates a very high temperature. Near-perfect combustion of hydrocarbons is always blue. Yellow indicates an imperfect combustion, i.e. lack of combustive agent (usually air) which causes production of soot, i.e. smoke. However, even a very rich mixture as used on a cold engine would not produce yellow flames, but add a yellowish hue at the end of blue flames. Red indicates a very bad combustion. A damaged engine burning oil would probably produce reddish flames. Hope this helps 
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#77
12-10-2010, 07:10 PM
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Is anyone familiar with the colour produced when the 'Ki gas' primer is used with full rich mixture, 100 octane fuel and a cold engine?
These are the only factors I can think of which might together produce a yellow flame, other than unburnt fuel igniting against hot exhaust stubs, which from video evidence already posted is more orange. Otherwise, I'm a little confused as to why our opinions were invited. All evidences posted point to blue flames and yet we're told we're wrong. 'Confused' of Milton Keynes |
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#79
12-10-2010, 07:16 PM
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 Temperature is related to efficiency of burning too, so it is linked to the flame colour, but as they are both effects and have the same cause I ignored it.. You could get yellower flames from an exhaust pipe that had a build up of soot inside or around the edges of the pipe, but this would eventually burn away.. maybe they start yellower because the pipes are dirty? I know that when they were testing the Spitfire at Boscombe Downs for night flights it was recorded that the exhaust flames were blue. |
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#80
12-10-2010, 07:16 PM
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Linear Mode
