Lawrence David unveils drag-reducing Tesco trailer By David Wilcox AFTER
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HATCHER Components' revolutionary new fairing for the underside of trailers (CM 4 April), Lawrence David is also attempting to reduce aerodynamic drag beneath its latest trailer built for supermarket chain Tesco.
The new device is the result of a joint project, with Lawrence David working with AB Airflow and Tesco fleet engineering manager Cliff Smith. Used in conjunction with AB Airflow's trailer sideskirts, the device is a plastic moulding mounted just ahead of the trailer's bogie, spanning the width between the skirts.
It shrouds the leading face of tyres on the trailer's foremost axle, while the central section is designed to funnel air smoothly below and past the axle tubes and suspension, thus minimising drag. AB Airflow owner Andy Bacon said it is better than the alternative ways of reducing the drag from the underside of trailers.
"Closing the gap across the front of the side-skirts is never 100% effective, and panelling in the whole underside of the trailer is too expensive," he explained. "It's better to let the air go through under the trailer, but clean up the flow so that it doesn't hit the bogie and can exit from the back. It's a simple solution and [the] cost isn't enormous," he added.
Bacon and Lawrence David technical director Brian Timpson expect to see fuel savings of 1% to 2% when the prototype axle airflow device is evaluated on the Tesco trailer during track-testing at Millbrook Proving Ground.
The trailer, a 3.97m-high, 13.6mlong tri-axle curtainsider, also incorporates other low-drag features, including AB Airflow's side-skirts and rear roof diffuser.
Although the trailer's height is well-matched to that of the Hatcher Freddie roof fairings on Tesco's tractor units, Lawrence David has added a radiused moulding to the upper portion of the trailer bulkhead.
Bacon said this refinement covers any minor height discrepancy and ensures the air flows as cleanly as possible from tractor fairing to trailer at all speeds, promoting laminar flow along the trailer's roof.