Quote:
Originally Posted by aerohead
The Fiat Aero Lab published an SAE paper back around 1986 in which some changes which reduced upper body drag increased under-body drag,or visa- versa, for a net zero effect to overall drag.
As I recall,grille-blocking could back-fire,if it shunted air below a car with a torture-chamber underside.
If your vehicle is very tall compared to width,you might treat it as a symmetrical wing section/strut,getting as much air around it rather than over it.And use the L/W= 4 2-D profile,rather than the 2.5:1 3-D form.
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That's kind of the direction I am heading in.
In my case 6' high from ground level, 6' wide, a clear 1+' of ground clearance and 8' of flat roof.
I believe this requires a different approach for a vehicle that is 4' high 6' wide, only 6" ground clearance and 4' of flat roof.
The dimensional differences result in it not fitting within the template profile at all, where as the std road vehicles are generally a rough fit.
I think the underside needs to be treated more like the solar racers, leaving the elevation, getting good smoothing and allowing more free flow, the question then begs, where to position the stagnation point at the front, as we basically want to achieve a natural distribution between top, sides & under.
My feeling is a split somewhere around 35% each side and 15% over and 15% under, with a stagnation point & radiator inlet in the lower half of the front under bonnet face, which is where it basicall is after the upper grille block, which I did with an upward tapered panel to get smooth transition to the bonnet.
When you say L/W of 4 in 2d profile does that basically translate to 2:1 in the symetrical form, so shorter than the template proportionally?