hpras wrote:Pieoter wrote:They probably already have enough downforce from the undercar tunnels and the rest of the package.
Possible only have a rear wing due to regulations, looks like an aero neutral profile.
Pretty much, just there mostly to tune the aero-balance of the car.
If it's effective enough to have a positive impact, it's effective enough to have a negative impact, yanno?
ESPN wrote:"On a higher downforce configuration, the endplates add more aerodynamic power and value, and we didn't need them," he continued. "The main plane looks very small because we can make a very efficient wing for oval events. It actually has just as much [aerodynamic] strength as the old wing and most of the time it's just providing a small amount of trim. It also has the nice side effect of lighter weight, which is a big factor for these cars."
The question is whether Chevrolet went too far in its quest for efficient downforce. Is the lack of rear-wing endplates contributing to the way the cars are suddenly snapping loose without warning, and to the seeming propensity for them to fly?
[...]
In an effort to maintain secrecy about their designs, Chevrolet and Honda did little on-track testing, by traditional standards, trusting their designs to wind-tunnel studies and computational fluid dynamics.
foxsports.com wrote:“It’s the first time we’ve run the speedway bodywork and it’s pretty hard to simulate that in a wind tunnel,” Penske told ESPN.
I don't think it's "pretty hard" to simulate representative conditions in a wind tunnel; I think it's impossible. As far as I'm aware, there's no wind tunnel in the world capable of accurately modeling the effects of yaw on a car that's traveling at 225+ MPH. So, they're flying blind here.
Literally flying blind
Without end plates, as much as a third of the wing, if not more, will effectively vanish as the high-pressure stream over the wing is pulled around the tips by the low-pressure stream underneath. The wing will "shrink" from the outside in at a rate generally proportional to speed: the faster you go, the more you lose.
And while conventional wing mounts inflict a smaller drag penalty than so-called swan neck mounts, they also reduce downforce from the inside out, and they introduce a greater sensitivity to yaw, because the surface area under the wing that's blocked by them will shrink and grow and shift from side to side.
Conventional (via
Mulsanne's Corner)
Swan neck (via
Mulsanne's Corner)
The net result is a wing that's very easy to stall. Even if it's only minor, any sudden reduction is bad news, because it doesn't require a major loss to cause a car with ~750bhp that's being driven at the limit to break traction and spin at high speeds. A driver would need supernatural reflexes to catch that sort of snap oversteer.
(By the way, I have no --- clue why I just wrote all of this. It's overkill like using a sledgehammer to swat a fly.
)