Why don't they round out the back of big rig trucks for aerodynamic efficiency?
968105
because it would CHANNEL that air flow DIRECTLY onto the vehicle behind the truck and thats not safe.
140128
the are trying to reduce wind drag
941165
Maybe you should try one of those little beanie hats with the propellor on top...If you get it spinning pretty fast, I'd bet you could get a few more inches  on your vertical and a hell of lot more hang time
23321
Not because they are hauling gravel But they have this sign because the back tires (despite the mud flaps) can act like a canon for loose stones/gravel on the road.\n\nThese are launched from the back tires.\n\n100 feet is a good distance to save your windsheild being hit by one of these.
1084157
They found that the second wing (bi-wing planes) was not helping the planes lift, but rather was just adding unnecessary weight to the plane.  Therefore it was inefficient.\n\nSome planes today actually have a smaller wing in the front and a larger wings in the back.   Also, some one plane known as the flying wing did not have a wing in the back.  In fact this is basically the design of our new stealth fighters and bombers.   \n\nSo new designs are coming forward all the time that find new design concepts in flying.
232819
You can't go wrong with a high flow exhaust and a high flow air filter, it helps the engine breathe a lot better and should also increase economy.  It might be a bit louder though...
124492
nope, just an urban legend. Same as people with pickup trucks driving with the tailgate down to reduce wind resistance (that one was actually proven to take more gas by the guys on Mythbusters)
413558
Yes,but it's providing downforce to stick car to track better.The car is going to cut the air,and you sure don't want it to go under,then car would lift up and get airborn.
448983
when you have complex machines, especially ones with rocket fuel, things on ocassion fail, they still do, rockets blow up every year. the trick is to minimize the failure through better design and materials and manufacturing. MIKE
4899
You are already stressing the components of the motor by almost doubling the cubic centimeters and in my opinion adding the extra horsepower of nitrous to a motor that wasn't ment for it would cause blown head gaskets, overheating and piston melt down. Those motors are touchy enough without the nitrous!
21948
They have taller, skinny wheels that are just high enough to keep the undercarriage from contacting the ground.  They use them just to get the truck into the 18 wheeler.  The wheels come in a different truck.
205067
I'd kind of like to be off the grid on a private island or the side of a mountain, I think.  Well, maybe in Montana or Wyoming.  But definitely fewer appliances and modern conveniences.  They make too much noise.  I'd like an all purpose vehicle for lugging grain, pulling a trailer, and carting the kids around.  No airplanes or rockets, no monorails, less toxic fumes, more open space.
378959
It could actually help another vechicle, I don't know about a large truck(semi?) but here read this\n\nThis slipstream effect works in the following way. As a single car races around a track, it creates a "bubble" of high-density air in front of it and a bubble of low-density air behind. The difference in the pressure between these two air pockets creates drag, the force that impedes motion. This drag force limits the top speed the car can attain. But if a second car pulls up behind the first, the slipstreams created by the two merge so that the first car losses its aft bubble and the second car loses its front bubble. This effect reduces the drag force each car experiences and both are able to travel slightly faster. \n\nhttp://www.aerospaceweb.org/question/aerodynamics/q0092.shtml
241393
I think the answer lies not in mechanics, but in aerodynamics and maybe the theory of turbulence. My initial answer was that they will need additional energy to keep the bicycle stable, which might be true. Then I had an additional idea. I guess you are talking about cyclists moving in a group, not single cyclists. This group creates an air pocket (aerodynamic shade) which moves together with them, making cycling easier for those who cycle inside the group. Cross-wind blows this pocket away (or changes its shape dramatically), thus making it harder, especially if you have gusts of wind.  I would conjecture that if the road were wide enough and the cross-wind is steady, the group would still be able to benefit from the aerodynamic shade.
1146635
Its mostly because of aerodynamics.With the Present propulsion method we cannot device those aircraft.Primarily circular aircraft shud rely on air for lift and it cannot take off as easy as normal one used now.\nMoreover Manoeverability cannot be achieved to the max with present technologies.\nBut who know it might be real one day..we cud have them.
266659
On my ford t-bird, if you lift the piece of plastic where the horn is located on the steering wheel, it comes of and you could easily stash a half pound back in there. Of tobacco of course, (the yahoo censors are every where)
12730
Ok, I thought you were pretty cool, until I came up to this question.  What's up with that??  I think, yes, you are the only one annoyed by it.  Well, maybe there are two or three like you.  Anyway, I'm one of those people that parks front end out.  Why, you ask?  Because, it's easier.  That's why you see lots of pickup trucks and long cars parking that way.  When you back out of a parking space, you don't have enough space, so you backup, turn your wheel, then move forward, then backup again, then you can get out.  Ok, so maybe there is enough space, but it just seems easier, and you can avoid accidents.  Also, it has to do with the car or trucks turn radius.  Pick up trucks have a horrible turn radius compared to a car.  Also, you see the back end of your car or truck better than you see the front.  The way vehicles are made today, you don't see the bumper. It's easier to backup into the parking space, and when you leave, you just put it in drive and go.  Just my opinion.