Quote:
Originally Posted by s_t
They are just rough hand sketches, but yeah, the drawbar needs to be long enough to allow the trailer to articulate (both side to side, and up and down) relative to the car. At least half the width of the car.
Deflectors on the car can't close that gap either, but I think some big trucks get part way there by using rubber deflectors mounted on back edges of the cab -
nothing gets damaged in the case of contact during severe articulation.
I understand this car to trailer gap is a major source of turbulence which will negatively affect the overall Cd. I don't know how big the effect is though?
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One study demonstrated a 12% drag reduction when the cab/trailer gap was faired in with an 18-wheeler.
As to motor home vs caravan setup:
The Vixen,5-cyl BMW Diesel-powered RV motor home could get as high as 29-mpg at around 55-mph.
VW Jetta TDIs,pulling up to 19-ft Airstream trailers have been reported at up to 30-mpgs.
I hope to test a trailer next month in the wind tunnel.I can't tell you anything 'til that's over.
Member BamZipPow has done a lot of trailer testing with his Toyota pickup.If you haven't seen his 1-wheel trailer thread you should check it out.
