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"A tea-tray will fly if you give it enough power."
- Popular saying of the aviation pioneers.
The first rash of blowover accidents involved hydroplanes. Then they appeared on drag strips. Race cars have always flown at the Nurburgring, but Le Mans is faster. Crosswind stability has always been a huge challenge for fully-streamlined bicycles. The four hazardous factors are speed squared, size, light weight, and attached flow on the low-pressure side. On a car, a rounded nose can reduce the effective aspect ratio of the unintended airfoil, while the more upright velomobile is much worse off. The size and height of a SUV would work against it.
In designing velomobiles, I try for enough balance that if it hit a patch of wet ice in a strong crosswind, it would get pushed sideways, but stay straight. In situations where there is more traction, that helps ensure equal slip angles at front and rear, so that gusts don't require much steering correction. To reduce the absolute force, it might be worthwhile to design shapes that barely maintain attached flow on the side in still air, so that they stall before generating much force, but that can also move the cp as it raises the cd.
Aye, BL, I was on about yaw, with the sideslip example. Most aircraft do trade drag for stability, but the canards get lift at both ends.
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