h a l f b a k e r y
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Vehicles of varying sizes and
speeds create different pressure
wakes behind them, and many
people like taking advantage of
that wake to save fuel.
Air pressure sensors at various
points along the vehicle tied to
some sort of instrumentation
that informs you when you are
in the wake ahead of
It will also tell you when you
are in the dirtiest air,
effecting your mileage
I suspect it should also be
speed activated to keep low
speed tailgating at a minimum,
where little if any advantage is
gained from the draft.
pressure sensitive surface
[xaviergisz, Sep 07 2008]
|maybe you could do this with a external coating on the vehicle that changes colour according to the air pressure (see link for one way of doing this).
|Just out of curiosity, if you're doing (say)
70mph, how close behind an HGV do you
need to be for this to have any benefit?
|forget drafting, the automotive industry
would die for an inexpensive way of doing
wind tunnel testing (this device would have
to be even more comprehensive). This is
not as simple as a single or multi point
pressure reading. Really a MPG reading
would be simpler: Use closed loop
feedback into a radar regulated cruise
control that "finds" the best position
|5-8 car lengths behind a tractor trailer?
|giblet have you actually drafted before? more like 1 to 1.5
car lengths before there is any benifit. Most rigs produce
a ducktail of turbulence at around five carlengths that
increases air resistance. However the whole system is
dynamic so the shape of both vehicles has to be taken
|Maybe if you had a caravan or convoy of
cars who wanted to draft together (in
rainbow order of course), the lead car
could use a smoke generator like
aerobatic planes use. Then each car will
see where there is turbulent flow or
laminar flow in relation to the wake of the
car in front of them and adjust for
maximum draft benefit.
|So, basically, we're talking about a device
to encourage you to stay a couple of car
lengths behind another vehicle at high
|I love the smell of natural selection in the
|The idea is also to keep you out of the most turbulent area, like the idea posted says.
|Respecting the stopping distances recommended by the highway code is already futile on motorways. If you leave the proper gap, someone will fill it.
|I did see something on the telly a while back where a train of cars were driving at high speed just a few meters apart. They were using some kind of autopilot that would apply everyone's brakes if the driver in front did.
|Luckily there is no draft in Canada.