AERODYNAMICS AND UNDER-SLUNG SOLUTION • With rising fuel costs, aerodynamics
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plays an increasing part in customer specifications, but truck manufacturer-designed aerofoil kits on the top of chassis cabs posed a significant problem for Carrier's engineers. Scott Dargan explains: We found a three-dimensional aerofoil around the refrigeration unit bolted to the cab. There is no way you can service or repair the unit, so our response was to bring it into the workshop, using a cherry picker. It became a two-man job."
A solution was needed, especially when a mobile engineer, not one linked to Carrier, Dargan points out, was spotted tilting a cab (with a fixed aerofoil) forward to access the refrigeration unit and was working between the cab and the body. "Again there was nothing in the marketplace. We designed a tilting aerofoil with Hatcher Components that optimises airflow: there are more than 250 out there. Operators are receptive, [but] without it we can't fix the unit on site, we have to bring it back to the workshop," he says.
Truck and trailer rental company Hill Hire specifies the tilting cab roof aerofoil. David Barlow, fleet director at Hill Hire, says the company worked with customers that wanted to move away from nose-mounted refrigeration units, preferring an aerofoil to maximise fuel economy. "With the availability of this new aerofoil system we will be able to revert to a more traditional nose mount set-up without compromising on safety,' he says. Carrier also provides under-slung refrigeration units but it's not the comprehensive solution it appears, explains Ross Thomson. "With some of the under-slung units you have to get underneath the vehicle where there are [other] hazards — banging your head, people driving off when you are underneath, working exposed to the side of the vehicle," he lists, And, remarkably, there are working at height issues too. In a workshop pit an engineer's head is at ground level so it requires a ladder to reach the underside of a truck. "An engineer has to service the evaporators in the back of the loadspace of the vehicle, you have to carry ladders to climb into the back and to reach the evaporators," he says.