Cuky wrote:
But tip of exhaust pipe (or more precisely, according to rules, last 100mm of it) do indeed point upwards for no less than 10° to the reference plane. Only coanda effect of bodywork under it and force of airflow over it do push it downwards.
I get that, but the Williams/Caterham fins on the coanda chamber are also below the specified exhaust cone (where no body work is allowed), therefore legal according to the letter of the law.
It seems weird that the rules specify a cone going up from the exhaust and they are pissed at people putting bodywork below said cone, it's like admitting your rules don't work in the first place.
The coanda is against the "spirit" of the rules, but ok according to the letter=FIA allows it.
The chamber fin is against the spirit of the rules, but ok according to the letter=FIA says this is prohibited.