On Oct 8, 3:35*pm, Adrian wrote:
Nige Danton gurgled happily, sounding much like
they were saying:

within any given class are likely to be fairly similar. As a rough rule
of thumb, increasing drag starts to come seriously into play from about
60mph upwards.
Drag cubes with velocity and so it may become important at speeds lower
than 60 mph.

Trust me on this... I've got plenty of experience with low-powered,
unaerodynamic vehicles. It starts to come into play at about 60.

I'm a cyclist and aerodynamic friction plays a huge role in
determining speed and above ~30kph the benefits of drafting behind
another cyclist are considerable. There's an energy saving of ~20% for
the first cyclist in a pace line and that rises to maximum of ~30% for
the fourth cyclist.

I really would be surprised in cars are so slippery that aerodynamic
friction does not play a significant role at speeds slower than 60mph.

What sort of vehicles are you referring to?

--
Nige Danton