The New Aerodynamic, Fuel Saving Teardrop Trailer

What is the Teardrop?

water teardrop The Teardrop, first conceived in 2006, is 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.

The concept is not complex or new. As early as 1921, the aerodynamic shaping of automobiles was developed initially by a German inventor called Edmund Rumpler, who subsequently launched the “Tropfenauto” or “teardrop car”.

Aerodynamics & Fuel Consumption: A Basic Guide

tropfenauto edmund rumpler It was not until the 1950’s and 60’s that aerodynamics played a more crucial role to the design of racing cars, where engineers started to recognise the benefits of higher speed and better stability.

Today, although you may not be consciously aware of it, the teardrop shape is all around us. Modern examples include the Toyota Prius and Honda Insight; both of which have exceptionally low aerodynamic drag. Brick-shaped cars no longer exist except in the garages of the most enthusiastic of collectors.

The teardrop shape is not limited to vehicles. Sports equipment too uses the simple concept to reduce the power-sapping drag and gain improved performance. Cyclists, skiers and tobogganists all use teardrop streamlining in their equipment.

toyota prius cycling helmet

Why then, almost a century later, has the proven technology not been used in commercial vehicles? Why is it that HGV’s continue to be some of the least aerodynamic shapes found on the planet and contribute some of the largest proportions of our countries CO2 emissions?

Goods-carrying vehicles are designed to carry as much load as possible, as efficiently as possible and to withstand the rigours exerted on them by the industry. Plastic moulding can be prone to damage and shaping of the bodywork can just eat into valuable load space. In addition, no-one previously considered that aerodynamics would play such a huge role on a vehicle 44 times heavier than its passenger-carrying counterpart.

For those that now own them, Teardrop trailers and rigid bodywork proudly stand out amongst the crowd; representing companies that demand better efficiency and care about their impact on the environment…

…companies that are perhaps now more attractive to those they supply.

Fuel Savings

Current Average: 11.3% (See case studies)

Internal Volume

10% extra volume

A standard 4.2m high trailer has 78m3 cubic capacity, compared to a Teardrop at 86m3.

There is no effect on load footprint. A standard 13.660m Teardrop trailer carries 26 UK pallets.

Impact on CO2 Emissions

CO2 emissions are directly proportional to fuel consumed (2.63kgs CO2 / litre Diesel).

One combination travelling 60,000 miles per annum at 8.5 mpg 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.

CO2 Calculator

Key Features & Benefits

Rapid, viable pay-back
Durable aerodynamic bodywork
Seamlessly compatible with your fleet
No reduction in payload capacity
A striking, aesthetically pleasing design

Aerodynamics & The Teardrop Shape

As aerodynamics accounts for up to 50% of fuel consumption (at cruising/trunking speeds), this is the area we have focused on with considerable effect.

Aerodynamics applies next to, and around the entire vehicle (Tractor-trailer/ Rigid chassis-bodywork). With this in mind, we not only had to consider the effect created by the trailer, but also had to understand the airflow trailing from the tractor as well.

The key, and most influential aerodynamic factor is Form/ Profile Drag. Air traveling over a smooth, airfoil shaped object will cause less drag than air traveling over an irregular, brick-shaped one. More specifically, the aim is to minimise any turbulence caused by a rapid change in object shape or surface direction. Turbulence is an area of rapid-flow, low pressure air that is created when attached laminar airflow traveling over a surface leaves that surface (separation point) due to sharp corner or shape change (relative to the initial direction of the air) and flows unevenly, creating vortices and eddies.

By streamlining a vehicle, you minimise the turbulence, reduce drag and lower fuel consumption.

In addition, the front bulkhead leans forwards slightly (keeping within 2040mm swing radius) to reduce the tractor-trailer gap turbulence and large radius cant rails further minimise vortex effects. The smooth roof lines not only manage linear airflow air well, they are designed to angle the airflow at the rear of the trailer (departure point) to minimise the turbulent area behind the trailer.

Standard 4.2m high trailer vs Teardrop Trailer:

Wind-tunnel and turbulence illustration

Teardrop trailer aerodynamics

Aerodynamic Airkits:

Historically, aerodynamic focus (tractor or trailer) has always been on the addition of various independent elements fitted to the existing bodywork and we have seen the inclusion of various designs; all of which have some degree of success and durability in a working environment.

Tractor cab top deflectors
Tractor side collars
Tractor-trailer gaiters
Side skirts (such as the DON-BUR Full-Wrap GRP skirts)
Roof scoops
Vortex generators

There have been well-documented case studies regarding the effectiveness of airkits and, in the trials carried out (comparing a tractor-trailer combination without any airkit with a tractor-trailer combination with full airkit), it was found that the tractor cab top deflector alone accounted for 85% of the overall 16% fuel saving acheived; meaning that the remaining 2.4% was attributable to the cab collars, trailer side skirts and other additions.

With this in mind, the Teardrop trailer alone had to achieve significant fuel savings, independant of airkits such as cab tob deflectors, cab collars and trailer skirts, which are now considered by many as standard. Therefore, all Teardrop trailer trials had to be done in comparison to a tractor-trailer combination that already had full aerodynamic styling and airkits.

Due to its snag-free simplicity, the Teardrop bodyshape arguably has greater durability than other aerodynamic alternatives; retaining its fuel saving benefits throughout its life.

The Teardrop shape is applicable to the following product ranges:

Box Van Trailers (Urban & 4m overall height options)
Curtain Sided Trailers (Urban & 4m overall height options)
Double Deck Trailers
Rigid Chassis Bodywork
Draw-Bar Combinations

The Teardrop shape is a Registered Design: number 000709423-0001: Patent Number: GB2443035

DON-BUR has set aside considerable funding to rigorously enforce both Registered Designs and Patent and will actively seek to claim any/all damages from any party believed to have made, or to be making any infringement, deliberate or otherwise.