Quote:
Originally Posted by ennored
Interesting! Makes me think about my flat sided and flat roof RV. And why something like a trailer tail works, but doesn't follow the template.
To be clear:
Only the roof is changed? (No plan taper)
The dashed line represents the template? (Like to see these drawn in 3D with round ("body of revolution" - clear?) superimposed)
And a question:
Think a curved surface (in side view) in place of each the "slashed" surface could do better? (easy answer being "yes", hard answer being what it looks like?)
|
*Yes,only the roofline is altered.
*Zero body side camber
*Zero plan taper
--------------------------------------------------------------------------
*yes,the dashed line is the faster version of the 'Template'.
*Buchheim offers a drag table for 'curved' rooflines of which the 'optimized',lowest drag configuration includes an up-kick rear spoiler.As perverted as I am,I could make no quantitative assessment of it based upon the limited information Buchheim provided.There's just no way to compare it to anything else.
-------------------------------------------------------------------------
*What Buchheim shows,is a fastback,who's roofline curves down into a maximum 27.5-degree slope of which the upper tip of the spoiler creates a 21-degree backlight-to-'boot' angle,terminating at 31% of the 'Template'.
Buchheim states that this 'optimum' angle is highly dependent upon the C-Pillar design.(so maybe he was reluctant to assign numbers since he could not represent the 3-D nature of the C-Pillar.)
-------------------------------------------------------------------------
As to Trailer-Tail,I think that AT Dynamics is working with something optimized for the arbitrary length limitation imposed by the USDOT,and also,creating something the drivers are willing to put up with.
I take dinner near the interstate each week and can tell you that a lot of the Mesilla Valley Trucking Co. rigs are going by with the Trailer-Tails folded and stowed.I don't know why this is so.