RE: Zero Nitro heads?
You're both right, Barry and Jeffie.
But... I was referring only to "real" engines...
Car engines and R/C cars in general, only became popular in the last decade, or so.
With the exception of tether cars spinning a prop, with a Rossi RIRE .60, does anyone remember any model cars more than 15 years ago?
And those 'mechanical mosquitoes' that run on an eye dropper of fuel, do use only high nitro, but their fuel was never offered to someone flying a sport .40 engine (for example), because it contained too much nitro and too much oil.