The hidden *real* drag coefficient

[freebeard]

If that is not under driver control it will feel janky.

[JulianEdgar]

Originally Posted by jakobnev

I keep thinking that rear-wheel steering could be used to turn a car a couple of degrees into the wind, but I wonder how comfortable it is driving a car that is a bit off.

I've had a couple of cars with four-wheel steer, and I read a really excellent article on this the other day.

I think yawing down the road would upset all the visual / mental cues that a driver knows to control the car eg if it is skidding.

[MeteorGray]

It's always funny to see a vehicle with an obviously tweaked frame yawing down the road sideways, sometimes called crabbing.

It seems to me that old pickup trucks are bad about that.

I always wonder what their tire life is.

[Piotrsko]

I had a VW superbug that had some interesting collision damage that "dogwalked" and got 60,000 out of the tires.

[MeteorGray]

Wow...60,000 miles out of a doglegged VW yawing down the road. I wonder how the alignment industry feels about that as they labor to get things to within the last ten-thousandths.

[Piotrsko]

AFAIK, alignment is relative to wheel direction. So if all 4 tires are set correctly where the body is pointing (to the tires) is inconsequential. When I had the bug altered to drive straight, the alignment shop had to adjust centerlines of the rear axles for equal distance and change some shims from one side to the other side

[MeteorGray]

That's a good point about the wheel direction v the body direction. It hadn't occurred to me that the wheels could be so aligned. It's probably easier to get the wheels aligned than to "un-tweak" a frame.

[Piotrsko]

Oh BTW: a bug is semi independent suspension such that the rear axle (s) are allowed to move about on their own. The dogwalk I had would not be repairable on a typical differential axle unless it was a mounting position error

[freebeard]

My Notchback was the best handling car I've had. Because I had a streetrod shop do a four-wheel alignment and they got the toe-in on the rear wheels right.

[j-c-c]

Originally Posted by JulianEdgar

My aero mods on the Insight are all to improve driving performance, not to reduce drag. So my undertray and diffuser are to give downforce, my rear spoiler is to give downforce - and my rear fins are to provide better straight-line stability.

That said, I have also tried to do aero modifications that are likely to reduce drag - and in the case of the rear spoiler / fins, they measurably do so (at least in light winds).

I haven't tested the rear fins / spoiler for drag in strong winds, so I can't answer the question about drag in these conditions.

I must have missed the above mentioned mods being analysed originally for handling/DF improvements, and not for drag reduction. I'll have to go back and review.

I would also like to research the detailed explanation for the use of slanted fins for mainly drag reduction for effectively a ground based vehicle.