Quote:
Originally Posted by Frank Lee
I don't think any of the trailing edges benefit from radii, nor do the bottom edges but, yes, everything on the leading and top faces besides that rearmost edge.
|
Crosswinds. Anything that allows wind to pile up against
and push is deleterious to all measures of performance.
The wind literally stacks against a non-radiused edge.
A semi, traveling either direction, pushes a bow wave that can easily upset a trailer of non-aero design. It does not hit head-on, and is far longer than the semi itself. The wind is reversing directions many times over a short period on the trailer surfaces.
The bottom is not so important, granted, but ground clearance must be low for this to be in force. A square white box, on beam axles, with the usual high clearance and narrow roll center is nothing more than a target, in a manner of speaking.
As you run the roads note that truckers will inform each other of a slow moving RV, and that as they pass they will move even farther away from it. It would be no trick -- but evil -- to pass at a high rate close up. One shot, one kill . . . .
For the same reason that once crosswinds reach 25 mph or above you will see 5'ers and the boxes pulled over for the day. I've towed in 35-mph constant with gusts to 60 and hardly noticed the trailer as it was the truck that was being pushed.
I have somewhere a quote about radiused edges and trailers. I'll see if I can find it.