Backwards. Aha. Rather different. (And, ever since, though we don't know it, "performance" ships have been _built_ backwards.) Puzzlingly, the context of the version I heard was it apparently revealed a new way of shaping ship sterns. Oh well, I shall see what explanations come my way in future.
On top of that, (according to someone in the meteorology NG) real raindrops are not shaped like picture-raindrops. Pressure on the leading surface flattens it while any tail collapses and the drop becomes a ragged disc.
Yup, thats correct good point, initially the drop forms normal drop shape but then rapidly turns into a ragged disc as you mention - presumably as the apparent wind speed increases the different forces contribute differently to shape.
Good idea!
Is that entirely to >
Well, more like a teardrop than a pickup without camper shell, which has a dead area behind the cab, a wind baffle at the far back, and another dead area behind the tailgate. Anecdotal evidence says driving with the gate down increase fuel economy about 10%.
Couldn't 4WD and high-clearance vehicles have a retractable front shield that the driver could remotely extend down below the grille at high speeds? Obviously this stuff needs to be computer-modelled, but if the underside is such a huge aerodynamic problem, it seems that cost-effective solutions could be provided.
Aerodynamic.
Cathy
That idea was on some concept cars at the auto show last year, they will proably start to appear in luxury production cars soon.
My guess is that the depression in the centerline is a way to reduce drag while maintaining headroom for the occupants.
Front spoilers and air dams are generally designed to prevent air from building up under the undercarriage and creating lift, which is bad for traction and cornering.
A simpler solution is to design the undercarriage to reduce drag so the air flows smoothly under the car.
Makes sense. At the same time, one probably gains a splash guard (which my Volvo 440s had and benefited from, on meeting puddles).
I thought it was only we aesthete Prius owners who cared about such details. So nice to know others are also getting it. :-)
Any credible test I have seen shows that driving with the tailgate down increases fuel consumption relative to driving with the tailgate closed. The "Mythbusters" beat this one to death. In their experiments (not perfect by any means), tailgate up beat tailgate down, but tailgate net (OE tailgate removed) beat both. I am not sure why the net would be better than either of the other options, but that was their results. Lots of other tests have shown tailgate up is better than tailgate down. It is possible no tailgate at all might be the best. At least that way you are removing some weight. For years the first thing my Father did when he got a new pick-up for the farm was to remove the tailgate and store it in the barn. Always looked funny when he traded trucks - beat up truck with a near perfect tailgate.
Ed
Interesting. Moreover, stuff doesn't fall out as much with it closed.
Anybody know whether a camper shell is better than with-tailgate closed? I would assume that the smooth-roof camper shells would be superior to those with a hump.
I drove a 1967 El Camino about 300,000 miles that had a removable shell & carpeted insert. They would improve my highway mileage 2+mpg and the weight made it handle much better.
Dan
oh ya, it was a 283ci V8
You would think so, but despite removing the tailgate from most of his pick-ups, my Father never had anything fall out the rear. But he was a careful driver. In almost 70 years of driving he never had a ticket and he only had one collision while he was driving (he hit a deer).
My Father always had some sort of farm dog. Most loved to ride in the rear of the truck. It always worried me that they might jump out while truck was moving. When I asked him if the dogs ever did that, he said, they usually only tried it once [and they learned their lesson - I don't think one was actually injured].
One more thing, when you ride in the back of a pick-up truck you notice that things in the bed tend to blow towards the cab, not out the back. Even with the tailgate in place and closed, things still tend to blow up against the front wall of the bed. This supports the idea that there is a rotating "bubble of air" formed in the bed.
Ed
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