Do lighter cars get better gas mileage? answer this.....?

Question

I not an expert on arrow dynamics, but I really want to know if you put a wing on your car, will say mounted centered on your cars balance point. Lets say this wing wasn't like those ricers trying to produce down force so there civic doesn't fly off the highway, but a wing that produced lift, this could improve the gas mileage of your car. I'm thinking it could even be mechanical in some way providing various amounts of lift, but on the highway you could make a 3000lb car drive like it was 2000lbs. That's a big *** difference, i just don't know how crazy drag would be on the wing itself, but I was just reading about something called the tube plane, a large percentage of its lift was created with the main body of the plane, technology is a far larger market than oil, driving around in vehicles shaped like bricks isn't helping MPG's. Any comments

Answer 1

A lighter vehicle would be more fuel efficient if the driver used the loss of mass to their advantage. If the loss of weight was used to gain more speed, the gain in efficiency would be lost. But if the driver were to drive in the same manner as usual, the lost weight would have a large advantage. The drag coefficient on the wing worries me a little, and also the wing may add some awkwardness to driving in general, but if done correctly could be a good thing. I am not an Engineer, but can see the advantages and disadvantages to both sides of the equation.

Answer 2

The idea of lift to reduce weight of a car, could create a hazard as far as handling and braking!  The use of high tech plastics and lighter metals will reduce weight and increase mileage.

Answer 3

Yes they do get better gas mileage.  It takes hp to get the car in motion, the heavier the car the more hp.  The more hp, the more fuel is consumed.

As far as the lift part, yes, but only in theory.  The handling and wind direction would cause this to not be very efficient.  If you removed all the variables then yes it would work.  Its not possible to eliminate the variables in a real world test so its better to just add drag and keep it planted to the road!!

Answer 4

A lighter car would get slightly better gas mileage than an identical car that weighed more.  Drive-line loss, aerodynamics, and engine efficiency also play a huge role in gas mileage.  A heavier, yet more efficiently designed, car would probably get better gas mileage than a lighter car.  For example, an underpowered economy compact car from the 1980's that weighted 2,000 lbs is going to get worse gas mileage than a 3,500 lb peppy luxury sedan from 2008.  Not saying weight isn't important, just making the point that it is only one of several factors.

In any case, your idea of using lift to lighten a car would not work, and would unfortunately only result in people careening to their deaths as they lost control of their cars.  This is basic physics and the law of conservation; you can not generate a lift force from nothing, energy must be consumed.  Lets take your 3,000 lb car for example.  If you're going down the road with a regular car, you have to move 3,000 lbs forward down the road, thus you need to consume fuel to move that 3,000 lbs.  Now if you put a wing on the car to create a 1,000 lbs of lift and you'll only need to move 2,000 lbs down the road.  The problem is that 1,000 lbs of lift doesn't come out of thin air, you'd need to put more power to the ground to move the car forward to generate that lift.  So now you're burning fuel to move 2,000 lbs of car forward and to generate 1,000 lbs of lift, thus resulting in the same net effect as just moving 3,000 lbs forward.   Remember, energy can not be created or destroyed, it can only change forms.  

This of course is a very simplified explanation and assumes 100% efficiencies.  Of course this is not the case and in reality fixing a big wing to a car would probably cause a significant loss in fuel mileage.

So I'm sorry, you just can't violate the laws of physics

Answer 5

Good idea in theory.  The problem is, the faster you go, the less control you would have over the direction the car would want to go.  You would get great mileage going in a straight line, but you had better not have to make any turns or stops.

Answer 6

Um, no, there is a thing called lift-induced drag, which means you will put more energy into generating the lift than could ever be saved because of it.

Not to mention that is gravitational weight you are talking about, it still takes as much energy to change the car's speed [Plus now you'll have less traction]

Also, this is speed-dependent, so you have no bonus to acceleration.

Certainly more aerodynamic cars or cars built with plastic bodies / aluminum frames go a lot better, though they kinda lack the weight capacity of heavier frames.

Answer 7

Your wing would create the same drag or worse. A 3000 lb. vehicle requires work to move in the inertia category. It is the work that it is required to move a given mass. Your wing would not decrease the mass.

Answer 8

The simple answer is yes.

As already noted the act of trying to create lift in order to decrease the effective weight of the car is possible, but flawed.

In addition to the already noted handling and safety aspects, lift requires a lateral speed, and this is difficult to maintain in urban or country driving environments anywhere.

The most effective method of improving your litres/100km is to use appropriate engine, car and road technology.  In most countries, this was gained by use of smaller vehicles, often favoured by big tax breaks.  In the US this is considered culturally unacceptable, and thus perpetuates the great 'gass guzzlers' in greater number than anywhere.

Engine type and driving style are also big influences on fuel comsumption.  Diesels are far more economical (20-50% lower consumption) than petrol engines, and modern diesels also have emissions that are just as good or better than equivalent petrol engines.  Euro standard biodiesel assists this.

Essentially, engineering on current technology will produce better economy and safer cars than trying to develop lift.

Answer 9

No as you accelerate the lift reduces the cars weight, however the wing increases parasitic drag which increases with speed. next problem as apparent weight decreases so does the necessary friction tires-pavement reducing grip which reduces acceleration also If you have a friend who is a pilot have them take you up on a day when you can experience the fun of a cross wind landing. now imagine driving down the road and suddenly the left side of the car lifts up off the ground and decides it wants to be on the right side. get the picture.

Answer 10

idk if Ferrari can produce a car with enough down force to double its weight at 180 mph.

It should be possible to create lift at 65 mph.

Probably not the prettiest thing in the world though.