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Don-Bur's "EcoStream" Aerodynamic Curtainsided Double Deck Demo


The efficiency claims for various new aerodynamic concepts on commercial vehicles have always been, despite wind tunnel or track testing, difficult for operators to fully appreciate.  For the first time, and to prove their claims, DON-BUR have engineered and manufactured two 13.7m “EcoStream” step-frame, tri-axle, curtainsided double deck trailers with aerodynamic sloping roofs, dedicated for free demonstration and trial purposes; one with a fixed secondary deck and one with moving Ratchet Decks.

The EcoStream fixed double deck has now been on continuous trial with various operators since August and, on a recent two week trial carried out by Palletnetwork operator STD Ltd, was rigorously tested both within their local area in Cheshire and on a trunk run from Congleton to Ellistown (120 miles round trip) using the same Iveco Eurotech tractor unit and driver.   STD’s standard Double Deck curtainsiders normally average at 7.5mpg for trunk runs (validated using Fueltec Data System), whereas the EcoStream achieved 9mpg; a difference of 1.5mpg.  This equates to a generous 16.7% fuel saving.  Four other double deck operators that have trialled the EcoStream have also reported savings figures consistent with those seen by STD.

Craig Stevens of STD says “We are often approached with various fuel saving claims but DON-BUR has provided us with a valuable opportunity to test their EcoStream double deck trailer under a real operating environment and we were delighted with the results.  We also noted that the trailer was very stable, followed the tractor unit well and was easier to manoeuvre than the other 6 trailers we currently have.”

On a standard “brick” shaped Double Deck Trailer, air striking the vertical front bulkhead is forced out of laminar flow over the top header, creating a substantial area of turbulence over/ round the length of the trailer and therefore drag.  The “EcoStream” Demonstrators have been engineered with a sloping roof design that starts at a 4m height at the front bulkhead (or engineered to suit operators tractor/airkit combination) and curves gently upwards by 880mm to full roof height of 4.88m at a point 4m further back.  The “EcoStream” curve maintains the aerodynamic laminar flow over this area and significantly reduces drag, as independent tests prove.

Richard Owens, Marketing Manager for DON-BUR says “From Don-Bur’s point of view, any savings figures we quote have to be accurate and validated.  One of our EcoStream demonstrators has now been out on the road since the summer and only recently have we decided to go public with the results of numerous independent trials.”  He also adds “As fuel is now a major part of overall operational costs, a 16.7% fuel saving is a major benefit and will have a huge positive impact on profitability.” 

Fixed Double Deck - As many double deck operators do not specify a secondary deck over the swan-neck to utilise the full cubic volume, the small loss of internal height at the front to achieve the “EcoStream” curve has little impact on normal capacity.  With a mesh floored (improved visibility) second deck to the rear two thirds (1911mm over main deck/ 1689mm over second deck) the area over the swan neck still has a 3280mm aperture at its highest point, creating a generous trailer capacity of 44 UK pallets.  With only one side support pillar at the swan-neck, the “EcoStream” also maximises ease of access.

Moveable Ratchet Deck (Registered Design No 2106753) - As an operationally flexible alternative to a fixed double deck, the second “EcoStream” Demonstrator incorporates 3 moveable Ratchet Decks, each with a side aperture length of 4.265m and 4 tonne capacity taking a total of 52 UK Pallets.  Each Ratchet Deck can be easily repositioned at 300mm height increments using a forklift and provides the operator with the facility to maximise the utilisation of internal space.


Client Contact

Mr Craig Stevens, STD Ltd                                01260 295 777




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Published: Thu 09 Nov 2006

Updated: Thu 11 Apr 2024

Author: Richard Owens

Published by: Don-Bur

Don-Bur (Bodies & Trailers) Ltd

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