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How to create lift using the underside of your car

The question is simple, Can we create lift by modding the underside of our vehicle? Not enough lift to flip us over, but enough lift that at certain speeds could affect the engine load thereby making our drive more efficient?

At first I was contemplating two ideas, dimpled bellypan, (Mangus effect).

Or some type of wing or spoiler built under the car or near and between the two tires to take advantage of that turbulent air.

Let hear some ideas, or just call me crazy and ignore this thread .. LOL

Quote:

Originally Posted by trikkonceptz (Post 48546)

Can we create lift by modding the underside of our vehicle? Not enough lift to flip us over, but enough lift that at certain speeds could affect the engine load thereby making our drive more efficient?

I don't think there is a practical solution for reducing rolling resistance through lift. In order to generate enough lift with some type of wing to make a difference the car will have to be going pretty fast - by which point aerodynamic drag should be a bigger factor than rolling resistance. Hang your car from a streamlined helium blimp and you can maybe have a win at around 10 mph - if there's no wind. Surround your car with a hovercraft skirt and add a big blower and you can reduce rolling resistance to almost nothing, but again, not very practical since you have to use a lot of energy to maintain the pressure under the car.

When you generate lift/downforce you also create an equal amount of drag. (Downforce is simply negative lift)

being aerodynamically neutral ( L = 0) is the best. teardrop/non cambered airfoil is best for low drag.

(See attachment, its the NACA 0015 airfoil. Its upper and lower surface are identical. at 0 angle of attack it generates no lift and no drag due to lift. There is still drag but its very low)

Why would you want lift? What would it accomplish?

Serious question.

Quote:

Originally Posted by skyl4rk (Post 48583)

Why would you want lift? What would it accomplish?

Serious question.

Less rolling resistance.

Quote:

Originally Posted by skyl4rk (Post 48583)

Why would you want lift? What would it accomplish?

Serious question.

When driving I notice that a couple of points off my engine LOD translates into large chunks of FE, so by lifting the nose/front end a hair you could stand to gain quite a bit of FE and not risk disaster.

I think you're a little confused.

a) lift makes for less traction. More speed = more lift = less traction at highway speeds = bad.
b) lift and downforce both create additional drag. You don't get something from nothing. (it is not equal, however, that depends on a lot of stuff)
c) more air under the car means more air along the turbulant underside
d) a wing in turbulance does nothing. Race cars try to smooth the air before their wing, or hang it up above the roofline for clean air.

Sorry if that sounded like grilling... I think you're just trying to stretch a concept a little too far. Yes, lower RR uses less gas, yes lift will lowing your RR, but it also affects other things... negatively.

Cheers!

Make a belly pan and lower your front bumper. You generate less lift, but you'll have less drag.

Rolling resistance with respect to increases in downforce are very minimal when compared to rolling resistance with respect to speed. You'll definitly end up on the wrong end of the stick should you try to increase lift. I'll see if I can get any graphs or info for you out of Hucho's book for reference.

Unlimited Hydroplanes use lift from under the hull to raise them out of the water. They would probably be the best example of what you are trying to achieve, but of course they are not worried about saving fuel. Any type of lift creates drag and may cancel out any gains made in rolling resistance if any.

Quote:

Originally Posted by trikkonceptz (Post 48546)

The question is simple, Can we create lift by modding the underside of our vehicle? Not enough lift to flip us over, but enough lift that at certain speeds could affect the engine load thereby making our drive more efficient?
Since the advent of Mussolini's Autostrada,and Herr Hitler's Autobahn,aerodynamicists have endeavored to eliminate lift altogether from passenger cars.Dr.Alberto Morelli succeeded with his "banana"car of the 1970s.Lift coincides with induced drag,which lowers mpg and can frustrate directional stability at high speed and during gust conditions.
At first I was contemplating two ideas, dimpled bellypan, (Mangus effect).
I am not familiar with "Mangus" effect( is that Magnus?),as associated with vehicle undersides.I believe he observed cylindrical artillery shells straying off course,due to the spin induced by rifled cannon barrels.He made the connection,that a spinning cylinder produced lift.That would not be an operating system for a car's underside.If Mangus is the fellow that first made the association with dimples,and golf ball boundary layer separation,this would also be a dead end,as for the Reynold's Numbers which our cars operate at,dimpling would make no difference,as critical roughness would be measured in thousandths of an inch,not inches.
Or some type of wing or spoiler built under the car or near and between the two tires to take advantage of that turbulent air.
A wing will not work in turbulence.If you block the area between the tires,you increase frontal area,increasing drag.
Let hear some ideas, or just call me crazy and ignore this thread .. LOL

It's good that your thinking outside the box,however,there already exists a body of empirical scientific data which has already addressed your theoretical inquiry,and no fruit was borne out of investigations.I recommend that you exploit what is already in the bag,then refine the small points from there.Good questions!