Lukraak_Sisser
Philosopher
- Joined
- Aug 20, 2009
- Messages
- 6,029
Fuel burns, what comes out is exhaust that forms smoke just like a car on a cold morning. However, car exhaust doesn't leave streams of smoke. If it does then something is wrong with your vehicle.
Jet fuel produces two main products when burning. CO2 and H2O. The water comes out at high temperature and saturates the air. Once it cools down it will condense. Unless the air is above 100 degrees, the boiling point of water.
Contrails form if the air cannot dissipate fast enough to disperse the water vapour.
In the same way your kitchen will fog up if you boil water.
Vehicles do this too, if the air is cold enough.
While there will be SOME unburnt fuel in the exhaust, engines tend to be designed to actually use the very expensive fuel to the fullest extent, not dump it out the back.