Tony Posted October 5, 2015 Report Share Posted October 5, 2015 I know some planes use smoke canisters but some planes namely the big ones have smoke coming from the engines..... What it it? Quote Link to comment Share on other sites More sharing options...
adam_r Posted October 5, 2015 Report Share Posted October 5, 2015 Its normally diesel or other fuel that is pumped in to the exhaust. The heat of the exhaust 'burns' the fuel but very inefficiently thus smoke comes out Quote Link to comment Share on other sites More sharing options...
liner33 Posted October 5, 2015 Report Share Posted October 5, 2015 yep diesel with a dye in it Quote Link to comment Share on other sites More sharing options...
Tango Posted October 5, 2015 Report Share Posted October 5, 2015 The smoke is produced by an independent installation which uses special mineral oil which although paraffin-based is biodegradable. It's pumped directly into/onto hot exhaust nozzles (piston engines) or exhaust fumes (jet engines) where it is instantly vaporised, not burnt. The 'smoke oil' nowadays has to be acceptable in terms of health, non toxic and certified as such for use. Various mixtures have been used in early development, including some with up to 25% diesel, but most fuels, alcohols, and other flammable substances present really serious hazards to pilots and aircraft (not forgetting spectators!), so is not used. Quote Link to comment Share on other sites More sharing options...
Tony Posted October 6, 2015 Author Report Share Posted October 6, 2015 Really interesting stuff..... Question though since the mix is a vapour wouldn't it be highly flammable. I know it's in the exhaust but flames wouldn't be desirable would it? Quote Link to comment Share on other sites More sharing options...
Sagitar Posted October 6, 2015 Report Share Posted October 6, 2015 Really interesting stuff..... Question though since the mix is a vapour wouldn't it be highly flammable. I know it's in the exhaust but flames wouldn't be desirable would it? Not all vapours are flammable. That stuff coming out of your kettle, which people call steam, is actually water vapour. From memory, I think for a vapour to burn it has to contain material that is flammable and its temperature must be above its flash point. I also seem to remember that there is a relationship between volatility and flash point. So the more volatile, the easier it lights. Quote Link to comment Share on other sites More sharing options...
Tony Posted October 6, 2015 Author Report Share Posted October 6, 2015 True but as said there is a mix of combustibles in the smoke so i'm just curious... Quote Link to comment Share on other sites More sharing options...
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