What is the difference between super petrol used in cars and Avgas used in light aircraft? How inter-changeable are they? RKM
Both are basically “petrol” ...aka gasoline...enhanced by additives to achieve a higher than natural octane rating, which for most cars needs to be above 90 and for most light aircraft needs to be more than 100.
So, Avgas is essentially a super-super petrol, and because it is inherently more important to have perfectly clean fuel when you are flying thousands of feet in the air than when you are driving on the ground, Avgas production and delivery is subject to much more stringent production and delivery systems. It also still uses lead as an octane enhancer and thus offers better lubrication.
The two fuel levels are theoretically interchangeable, and for high performance cars with especially high compression engines Avgas can be beneficial.
But for most cars it is not necessary and could upset combustion balances and ultimately cause some damage. Some small planes might risk car-level octane rating and still fire up and run but would be well advised to stay quite close to the ground.
The same applies to paraffin...a distillate aka dual purpose kerosene (DPK)...which fuels everything from tilly lamps and camping stoves to, um (fasten your safety belt), Jumbo Jets!
The super clean, super stringent version is called Jet A1, but is basically the same stuff you might use to clean old wax polish off a parquet floor.
