Following independent trials. Altrincham-based trailer and body builder Cartwright Group
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is claiming that its new Cheetah Fastback trailer can cut fuel costs by 10%.
For the trials at the MIRA Proving Ground, in Nuneaton. Cartwright pitched a tandem-axle 4.0m-high standard box trailer against the Cheetah Fastback, using a 4x2 tractor and with both trailers loaded to 38-tonnes CWW.
'Ibe results have been endorsed by operational trials by TNT on the first two 4.0m-high Cheetah Fastback trailers running out of Holland. Regular trips from the Arnhembased TNT site to Switzerland have seen a 10% fuel saving compared with trailers without aerodynamics, says Cartwright Group director Steven Cartwright.
Independent track results and the TNT road trials show that the trailer, an extension of the original Cheetah system, works, but pinpointing an exact possible saving is hard. Part of the track tests compared the Cheetah Fastback with the original Cheetah trailer, which has rounded caps, clear air flow through the chassis and axles, and a small lip on the cab collar of the tractor. Results showed a 3%-4% saving over the established Cheetah system.
A design with varied benefits
Cartwright says the trials focused on the tandem-axle trailer to show parcel companies, which tend to predominately run tandem-axle trailers, the direct benefits. However, he stressed that the design can have benefits for any trailer travelling on long motorway journeys.
With a 10% saving, Cartwright argues that the Cheetah Fastback will pay for itself in one year. "The Cheetah [package] is priced at £1,400 and Cheetah Fastback [package] is £1.800 to £2,000. There are lightweight options available too," he says. 'Our chart shows that you can save more than £5,000 per trailer [running over 160,000krns annually]. It more than pays for itself inside 12 months."
Again, this has been backed up by the TNT operational trial, says Cartwright.TNT runs its trailers over approximately 140,000km a year, and the projected saving from the trailer running to Switzerland is 0,500.
For the test. Cartwright Group specified the Cheetah Fastback box-van with a tandem-axle on air suspension, which raises and lowers 200mm the control valve is fitted to the offside of the bulkhead. The chassis is wedge-shaped and the roof tapers towards the rear.
"Ibe sidewalls taper 40mm on both sides at the rear to create a backdoor aperture of 2240mm. Cartwright Group has designed a new side guard system with hinged panels for access to the tyres, and pulled the rear side guards into the chassis I-beam to help reduce drag. -The [original] Cheetah trailer will adopt the side guards on the new Fastback," says Cartwright.
The clear airflow underneath is retained from the original Cheetah system. as well as the circular under-run bar at the back. The tail-lights are built into the bodywork, and the trailer ran the test using standard 385/65 R22.5 tyres. The new design is 200kg heavier than Cheetah.
Cheetah Fastback will available on the group's whole product range, although Cartwright imagines it will be the 4.0m. 4.2m and 4.5m trailers that will benefit the most. One company has a tri-axle curtainsider in build. •