Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Why don't vehicles have aerofoils to partially take the weight of the car?

Isaac Zachary · 06-03-2021, 02:29 PM

Maybe it's an apple to oranges comparison, but for some reason this thread has me thinking about some of the similarities to hydrofoil boats.

Anyhow, I don't think anyone has actually attempted to make a vehicle that specifically has air foils designed to create partial lift for the purpose of reducing rolling resistance.

But what if we were to try to do that.

The air foil(s) would have to support a lot of weight and so would need to be strong. But that would add weight.
The lifting force would be affected by speed. This wouldn't help at low speeds. So a vehicle built this way would likely have more rolling resistance at lower speeds due to the weight of the air foil(s). It also means that an airfoil that takes off half the weight at 60mph might take off a lot more, maybe all, at 75 or 80mph, unless you have some way to adjust it, such as its size.
For it to be beneficial, it would have to create less air drag than the amount of rolling resistance that it removes. I do believe that can be achieved. If air foils were terrible air drag makers then things like sail planes would not work.
Ideally we'd want the air foil(s) to be adjustable, so that we could remove the lift when needed, maybe even creating down force on the fly. How fast can the air foil(s) be adjusted is a good question, as well as what would be controlling it (them).
Is there any other tech that could reduce rolling resistance that would be more practical than wings? For an example, extremely low-rolling resistance tires of some sort? Putting train tracks on all roads? Maglev? Ultralight vehicles?

One idea I had years ago was to make one big solar panel that would be installed raised up off the top of the car. That way you could have a solar panel that takes up the entire square footage of the top of the vehicle without covering the windshield and rear window in PV cells. The solar panel would have to be curved to follow the air flow line over the top of the car. Small movements in tilt would likely create substantial lift or down force with such a solar panel, or so it would seem to me.

06-03-2021, 02:29 PM	#129 (permalink)
Isaac Zachary High Altitude Hybrid Join Date: Dec 2020 Location: Gunnison, CO Posts: 2,075 Avalon - '13 Toyota Avalon HV 90 day: 40.45 mpg (US) Prius - '06 Toyota Prius Thanks: 1,128 Thanked 584 Times in 463 Posts	Maybe it's an apple to oranges comparison, but for some reason this thread has me thinking about some of the similarities to hydrofoil boats. Anyhow, I don't think anyone has actually attempted to make a vehicle that specifically has air foils designed to create partial lift for the purpose of reducing rolling resistance. But what if we were to try to do that. The air foil(s) would have to support a lot of weight and so would need to be strong. But that would add weight. The lifting force would be affected by speed. This wouldn't help at low speeds. So a vehicle built this way would likely have more rolling resistance at lower speeds due to the weight of the air foil(s). It also means that an airfoil that takes off half the weight at 60mph might take off a lot more, maybe all, at 75 or 80mph, unless you have some way to adjust it, such as its size. For it to be beneficial, it would have to create less air drag than the amount of rolling resistance that it removes. I do believe that can be achieved. If air foils were terrible air drag makers then things like sail planes would not work. Ideally we'd want the air foil(s) to be adjustable, so that we could remove the lift when needed, maybe even creating down force on the fly. How fast can the air foil(s) be adjusted is a good question, as well as what would be controlling it (them). Is there any other tech that could reduce rolling resistance that would be more practical than wings? For an example, extremely low-rolling resistance tires of some sort? Putting train tracks on all roads? Maglev? Ultralight vehicles? One idea I had years ago was to make one big solar panel that would be installed raised up off the top of the car. That way you could have a solar panel that takes up the entire square footage of the top of the vehicle without covering the windshield and rear window in PV cells. The solar panel would have to be curved to follow the air flow line over the top of the car. Small movements in tilt would likely create substantial lift or down force with such a solar panel, or so it would seem to me. __________________