Quote:
Originally Posted by JulianEdgar
We can very quickly see that you have not measured aero pressures on real cars on real roads (or if you have, you've forgotten what you did) when you write stuff like that!
For example, I don't know of even one road car that has a high vertical downwards force at the nose. And as for pressures at the area of the roof apex not impacting lift, well....
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* The raw pressure data I'd theoretically measure would have no context, unless we had the actual axle loads.
* You'd want to take the curb-weight, plus all passengers, plus luggage / cargo, up to full-rated allowable gross weight, determine from the front/rear weight bias, the actual static axle loading, compared to any 'lift', whether positive or negative; and 'see' what that looked like.
* And it may not have registered, that a streamline half-body begins its boat-tailing at the drivers shoulder, at the roof apex.
* The boundary layer doesn't 'grow' as with conventional bodies. The velocity gradient is continuously falling, across a diminishing cross-section, while maintaining a gently-increasing pressure gradient, which the boundary layer 'loves.'
* By default, being 'streamlined', the profile cannot trigger separation. There is no pressure drag. Only friction drag, and that is at the observable minimum of all bodies, by definition.
* You might be surprised by a streamlined half-body.
* According to the airship designers, at zero-yaw, a streamline body of revolution produces zero-lift.
* 100% full, local atmospheric pressure is acting on the nose.
* At a 2.5:1 L/D ratio, perhaps as high as 91% of local barometric pressure is available over the aft-body.
* This would be the same for the half-body.
* The diffuser would counteract any rear lift.
* Hucho stated that , for passenger cars, neutral lift is a perfectly acceptable target.
* A dorsal appendage could address any crosswind / gust issues. It won't be long before roadside meteorological monitoring stations will communicate, directly, in real-time with vehicle AI, providing 'guidance' with respect to any problematic weather scenarios.