Cars use gasoline but jets use something closer to diesel, maybe kerosene, that’s less combustible. Wouldn’t they need a _more_ volatile or explosive fuel to get the most thrust for performance?
In: Engineering
One of the biggest differences is intermittent deflagration, which is what cars do, and continuous combustion, which is what jet engines do.
Car engines intermittently ignite fuel air mixtures to produce a discontinuous sequence of explosions. This kind of explosive combustion is a lot less efficient and tends to be dirtier than continuous combustion. Continuous combustion can be tuned to cleanly burn much heavier molecules, like kerosene. Also, due to the extremely high temperatures achieved by jet engines, these big heavy molecules experience some thermal cracking before they oxidize. Thermal cracking is where exposure to extreme temperatures and a limited amount of oxygen breaks big heavy molecules into lighter molecules due to the violent molecular vibrations that occur at extreme temperatures. Thermal cracking doesn’t happen well in discontinuous explosive combustion, but it can be optimized in continuous combustion such as in jet engines.
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