Quote:
Originally Posted by aerohead
The photo of the tractor-trailer is not real,yes? I've seen enough actual and photographic windtunnel smoke investigations that I'm highly suspect of the authenticity of this image.
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We would like to clarify that this illustration is NOT an actual windtunnel photograph - as many here have deduced.
This is an illustration and mark it clearly as such.
Nevertheless, as also pointed out here, the illustration is based on CFD work and further anlysis. The problem that we had was full-scale wind-tunnels and attempting to get a decent photograph - which proved impossible: hence the illustration.
We are fascinated by this design and a claim of CD 0.12 is quite staggering. However the design at the front needs revising.
The lower skirts are shown to extend forwards around the wheels of the tractor unit. This is not practical due to articulation.
For guidance, the standard ISO swing clearance for the tractor, rearwards of the kingpin is 2.3m.
General measurements for guidance...
Forward maximum swing clearance to front of trailer (as a radius from kingpin) is 2.040m
Maximum length from kingpin to trailer rear: 12.0m
Maximum width (dry freight) 2.55m (or 2.6m for insulated bodywork)
Maximum height: none in the UK - 4m in most of Europe. The vast majority of trailers in the UK tend to be 4.2m, with Double Decks regularly reaching 4.88 (16').
Lowest floor height at the back (for straight-frame trailers on 1.250mm fifth wheel height) on 385/55 R22.5 is 1.1m above ground.
Lowest floor height at back (for step-frame trailers) on 215/75 R17.5 twins is 870mm above ground.
The use of a Teardrop roof is not limited to the UK - indeed we have a Euro version within 4m and it does show a marked improvement (current analysis shows circa 8% fuel saving). However, this design is now fully patented in Europe.
The one major thing you need to be wary of is the rear design. The trailer width cannot taper inwards too much due to loading and height needs to be kept critically as high as possible. Not good for aerodynamics, but as said elsewhere here, the Kamm effect can be used.
We would be very interested to know more about your work.
Regards
Don-Bur