Dolphin offers a no-tears solution

The teardrop or dolphin trailer – a new concept in trailer design hardly noticed at the Johannesburg International Motor Show (JIMS) 2011 – has arrived in South Africa to complement the efforts local manufacturers are making to provide fleet operators with solutions that will help reduce the cost of road freight transport and lower carbon dioxide emissions.

South Africa’s trailer designers are most innovative when it comes to designing trailers for local conditions, with new designs popping up all the time. In many cases, they follow overseas trends and designs that could work here, but usually have to be adapted to cater not only to our harsher operating conditions, but also regulations governing our maximum vehicle dimensions and axle masses, which are generous compared to the rest of the world.

But they also come up with homegrown designs that are of world-class standard. In the case of tippers, for example, there have been ongoing chassis modifications and newly shaped tipper bodies incorporating new hydraulic systems. Last year even saw the arrival of a multipurpose trailer from Top Trailers (designer of the original Sloper), which has also introduced sliding bin tippers, tridem side tippers and interlink side tippers.

The multipurpose trailer was in response to a radical new concept from Buks van Rensburg, owner of Buks Haulage Limited (BHL) Zambia, which hauls copper concentrates on the Copperbelt one way, and sulphuric acid or cooking oil on the return leg.

It saw Top Trailers and Flexi Manufacturers, the well-known producer of liquid and chemical tankers, producing a tridem semi trailer that has a 28.5-tonne side-tipping bin in the middle of two 8 000-litre tanks. Another version consists of a flatbed replacing the tipper body in the middle to transport copper plates or a 20-foot container.

Another major development last year was the introduction of the Imvubu (“tough as a rhino”) seven-compartment, 50 000-litre aluminium tanker by GRW Engineering, whose tankers are so good they have been exported to the United Kingdom. The Imvubu is a cost-effective solution for fuel tanker operators who want to deliver sealed (SPD) or metered consignments, or both, to fuel stations. This design incorporates the latest instrumentation equipment and vehicle components from the United States and Europe, including BPW Ltd’s axles, suspension and ECO Disc brake system, released late in 2010.

Durban-based Serco came up with a new drive-through interlink trailer combination for Bakers and Manline with standout features such as new inter-leading double centre doors and ramp, a sliding fifth wheel and an aluminium rollover door – all of which allow a forklift to drive through from the rear trailer to the front trailer for through-loading.

Several of these and other new designs were exhibited at the JIMS 2011 Truck & Bus Show late last year, including other advanced tipper designs by Top Trailers and a 65m3 high-volume semitrailer from Afrit.

Surprisingly, as I write (early January 2012), there have been few – if any – trade press reports on the latest exciting offering from SA Truck Bodies/Henred Fruehauf: the local version of the aerodynamic Teardrop semitrailer – a world first – which has become all the rage in the UK and Europe among leading fleet operators because it offers fuel savings averaging 11.3% and more payload volume than a standard trailer.

Built for Lafarge South Africa, it was exhibited at JIMS, and South African operators can now purchase it as a semitrailer or in the form of an interlink – another world first.

The arrival of this new concept in trailer manufacture in South Africa is an important event – not only for fleet operators, but also to their clients who want to be seen making a contribution to reducing CO2 emissions in this country.

But let us first explain the teardrop concept:

Scientists have known for almost a century that the liquid teardrop is perfectly shaped from an aerodynamic point of view. Aircraft designers discovered this with the aid of the wind tunnel – the Brothers Wright had one – and knew about its low co-efficient drag (cD or cW), which was later to be determined through extensive computer analysis to be 0.27.

A German inventor, Edmund Rumpler, is widely reported to have been among the first to introduce the concept to the automotive industry in 1921 when he developed and launched the Tropfenauto, or “teardrop car”. This was followed in the 1930s by small teardrop camping trailers that gained international popularity when magazines such as Mechanics Illustrated published plans for these so-called “trailers for two” that could be hitched onto a (still brick-shaped) car.

It was not until the 1950s and 1960s that aerodynamics played a more crucial role in the design of racing cars, where engineers started to feel the need to match higher speeds with so-called lift and down forces, and had to add wings and spoilers to achieve better road stability, including cornering.

Aerodynamics was introduced to other sports equipment to reduce the power-sapping drag and to gain improved performance. For example, cyclists, skiers and tobogganists all use teardrop streamlining in their equipment.

It then moved into the design of passenger cars by the likes of Citroën, Porsche and Chevrolet and, more lately, in that of the Toyota Prius and Honda Insight.

It also moved into heavy commercial vehicle design, but was mostly limited to the front end of the truck-tractor through the use of a rooftop spoiler, an under-run and side skirts, plus side skirts on the trailer.

What is now called a revolution in trailer design is the result of designers looking at the entire vehicle combination – not only the truck-tractor – and extending the teardrop principle to the shape of the trailer.

According to MAN Nutzfahrzeuge, almost 40% of the total energy expended to keep a 40-tonne truck moving at a constant speed of 85 kilometres per hour on a flat road section is to overcome air resistance alone.

In Europe, however, strict limits are imposed on the aerodynamic improvements that can be made to trucks by manufacturers due to the legal requirements governing length and height. When developing the current TGS and TGX truck series, MAN was able – through aerodynamic streamlining – to improve the air resistance by 4% compared to the TGA predecessor model.

MAN said that, taking these existing general requirements into account, the best possible aerodynamic performance of the conventional front-drive truck had therefore already been achieved. MAN added that, if the legal (European) requirements were to change, the air resistance of trucks could be significantly reduced even further.

To prove the point, MAN presented an aerodynamically optimised semitrailer truck at the IAA 2010 in Hanover, but this time based on the “flow topology of a dolphin’’. The tractor, that had been extended by 80 centimetres together with the semitrailer, increased in height by 20cm and had a truncated rear end, achieved a sensationally low cD value of 0.30.

Maximum vehicle length and gross vehicle mass in most of Europe are limited to 16.5 metres and 40 tonnes respectively. Since the IAA 2010, and with European Union governments seeking ways to cut their CO2 emissions, MAN, as well as Volvo and Renault, have been pushing for new 25-metre, 60-tonne articulated combinations. They say these are a greener alternative to the shorter trucks now plying European roads, as they can carry increased loads at a lower fuel consumption and reduced CO2 emissions.

Such trucks, also known as longer and heavier vehicles or Gigaliners, already roar along roads in the US, Australia and South Africa – allowing a maximum vehicle length of 22m and a GVM of 56 tonnes.

But other than in the Netherlands, Finland and Sweden, they are still outlawed in Europe where roads are generally too narrow; and environmentalists, as well as the road safety brigade, are strongly opposed to the introduction of these “dangerous behemoths”.

The truth is that a leading UK trailer and truck body manufacturer, Don-Bur, based in Stoke on-Kent in Staffordshire, has been supplying teardrop-shaped semitrailers to many reputable fleet operators such as DHL (on contract to Mark & Spencer), UK Mail, Royal Mail and Wincaton Lafarge and now also to Lafarge in South Africa.

Don-Bur claims it was the first to come up with the teardrop concept in 2006 and, having patented it worldwide, it appears to have stolen some kind of a march on MAN.

Commenting in The Economist on MAN’s Dolphin concept, Don-Bur said: “Whilst being the most aerodynamically efficient shape, it also restricts rear aperture and load space to the point where viability is questionable. In addition, their design would appear to be in breach of the Don-Bur Teardrop trailer patent!”

Don-Bur describes its concept as “a unique commercial vehicle shape that mimics the natural and perfect aerodynamic properties of a liquid teardrop. The streamlined shape generates significant fuel savings and an increase in cubic capacity.”

Commenting on the rationale behind pursuing the concept, it said truck-tractor and trailer combinations have been some of the least aerodynamic shapes found on the planet and have contributed some of the largest proportions of the country’s CO2 emissions. “This because they are designed to carry as much load as possible, as efficiently as possible and to withstand the rigours exerted on them by the industry,” said Don-Bur.

“Plastic moulding can be prone to damage, and shaping of the bodywork can just eat into valuable load space. In addition, until a few years ago, few considered that aerodynamics would play such a huge role on a vehicle which is 44 times heavier than its passenger-carrying counterpart.”

According to the company, in the UK a standard 13.66m long, 4.2m high trailer has 78m3 cubic capacity, compared to a 13.66m Teardrop trailer at 86m3 – adding that there is no effect on load footprint. It says a standard 13.660m Teardrop trailer will accommodate 26 UK pallets.

The impact on CO2 emissions is directly proportional to fuel consumed (2.63kg CO2 per litre diesel), and one combination travelling 60 000 miles per annum at 8.5 miles per gallon will consume 32 080 litres of diesel and generate 84.37 tonnes of CO2. A 10% reduction in fuel use will cut CO2 emissions by 8.4 tonnes.

The initial Teardrop vehicles provided 10% extra volume and fuel savings averaging 11.3%. Don-Bur has provided a number of case studies that can be accessed via its website.

Later last year, Wincanton Lafarge and Don-Bur worked closely to design and manufacture the first 15.65-metre teardrop pillarless tri-axle unit in anticipation of the specialised vehicle orders. The new 2.05m longer trailer was reported to have benefited from an average 15% additional load capacity, or four extra pallets – a feature that was expected to increase efficiency and reduce fuel consumption and CO2 emissions further. Officials of the UK Department for Transport approved the controlled trials of the so-called high-volume trailers (HVTs) in November last year.

One of the reason Lafarge SA is the first fleet operator to go for the concept is that its French-based parent company was entered into the global Dow Jones Sustainability Index in 2010 in recognition of its sustainable development actions. The organisation had a target of 20% reduction of CO2 per tonne between 1990 and 2010, and surpassed this target by achieving a 21.7% reduction.

The organisation has now gone one step further in enhancing its sustainability initiatives by embarking on a massive CO2 reduction plan targeted around its distribution, including that in Africa. This plan is now being implemented by Lafarge Gypsum South Africa in partnership with Don-Bur, SA Truck Bodies and MAN Truck & Bus.

The local subsidiary says technical developments have embraced creativity to meet the business’ core objectives of introducing one of the safest vehicles operating on South African roads; designing a vehicle specification that would inherently reduce the company’s carbon footprint; and increasing payloads to enable fewer trips.

Jean-Paul Croze, managing director of Lafarge Gypsum South Africa, announced that he intends to create a sustainable environmental inheritance in South Africa through the implementation of the most advanced technology available in the world. According to him, the new vehicle specifications for Lafarge Gypsum South Africa will become the benchmark for logistics across Africa.

“Aerodynamics, rolling resistance, inertia, gravity as well as drive-line losses are the four major fuel-consuming culprits of transportation. While the Teardrop concept of Lafarge mimics the perfect aerodynamic properties of a natural teardrop, its attention is on lowering turbulence and drag. Less drag results in lower fuel consumption,” he added.

Controlled trial results in Europe of Lafarge Teardrop trailers have shown fuel savings of 8.5% at a “negligible” increase in capital cost, no effect on residual values, no reported operational issues, and an increase in payload by reducing the vehicle’s tare weight by 1.5 tonnes.

Lafarge said that the second generation of Lafarge Teardrop trailers that followed were further advanced by the pillarless design; further use of lighter materials, which reduced the net tare weight by a further 1.2 tonnes; buckleless curtains; and side skirts (a potential area for storage); and further fuel savings of 1.5%.

“From the learnings gained within Lafarge Europe, the Teardrop concept is now being introduced into South Africa in three variations (Super-link, tri-axle articulated vehicle and a 15-tonne Rigid). Formal trials are being conducted to quantify the fuel saving benefits, but these are forecast to be around 9% to 13%,” it added.

“Payloads of all three vehicle types will increase significantly and will set the benchmark for what is legally achievable on South African roads.”

Udo Rypstra