|
As an equal opportunity offender, I'm not going to quote anybody, I'm plucking out comments sans credits.
> I didn't join here because I want to squeeze every drop of gas I can.
:-) That's exactly why I joined! I already do all the communicating I need to on car DIY in general, and aero performance mods in particular. I hang out here for information and discussion about automotive efficiency.
> Along with drag, anyone that drives on the highways and freeways should also be concerned about aerodynamic lift.
I'm not sold. My mom drives on highways and freeways and doesn't think twice about lift, and I'm not going to educate her because I don't think it would be an improvement. If she finds herself in an oversteer situation (unlikely with her driving habits) I want her to remember to steer into the skid, I don't want her distracted by her conscience yelling at her in its Jimminy Cricket voice, "See, I told you you should have bought a spoiler."
I sure think anybody doing competition driving (even autocross, a motorsport where average speed is lower than freeway speed) should be concerned about aerodynamic lift...well, kinda; in road racing we're concerned with increasing downforce rather than decreasing lift, and have been since about 1964, but that's gotten some people in trouble. Ground effect cars that lose ground effect (over a bump for example) can do a sudden transition to the land of lift, best shown by the flying Mercedes at Le Mans. Anybody going over 200 mph on salt needs to be concerned about aerodynamic lift--if you're putting 400 horsepower onto a slippery surface through your rear wheels, a small loss of load can spin you, and at 200+ darn near any car is going to produce lift if you put it sideways--a sideways car has about quadruple the aspect ratio of a frontways car and if it has left-right symmetry then sideways it's a symmetrical airfoil--it'll be inefficient but it'll be high lift and I think you could fly a school bus if you got it sideways over 200 mph. I even think you should be concerned if you're hooning around at 120 and cornering hard enough to make the tires squeal. But the question before us is, is aerodynamic lift a real problem to ecomodders.
> When air pressure builds up and generates lift, it reduces your tires' available traction...
I will stipulate that lift reduces traction. I have a bit of trouble with the "air pressure builds up and generates lift" part, but as to lift resulting in loss of traction, I nod my head in agreement.
> Since to some people it seems to be completely foreign, I thought they would like to know it's common knowledge to those in the real world.
We have lots of different takes on what's significant--and even on what is common knowledge to those in the real world. I read these posts and see complete agreement that lift reduces traction, but questions re it being a real problem in the context of ecomodding. I'm on the fence myself. It's not that the concept is completely foreign, I just wonder if it's significant.
For example, in pursuit of high mileage, I'm looking into low rolling resistance tires. These tires reduce traction compared to many other tires. Were I the sort to drive at a given G force (say, half a G) regardless of my environment, high mileage tires would increase the likelihood of me spinning out of control. Yet nobody has started a thread of "High mileage tires--a real problem" even though they'd be a real problem in the 200 mph club at Bonneville. Is the lift issue of similar significance at ecomodding speeds and ecomodding driving style?
I'm genuinely interested in finding out. I'm considering a low drag body inspired by pre-war racers, when speeds were low enough that drag was much more important than downforce.
|