Double/Triple : Airtab

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Received June 22, 2007

Aitab,

I have a 2005 Freightliner Argosy cab over and pull a 35 foot tri-axle lead van; with a forty-eight tandem axle van behind it. I run 5 days a week from Edmonton to Grande Prairie; roughly 600 miles. 2 weeks testing without airtabs with an average gross weight of 115,000 lbs; I averaged 6.2 miles pre gallon; after installing airtabs on both trailers and my tractor; I now average 6.8 miles per gallon. This gives me a return after my initial investment after fourteen trips. All the testing was done at 100 km/h (62.1 mph); as I'm restricted to these speeds for extended length vehicles in Alberta.

One thing I noticed immediately; on down hills the truck tends to pick up speed quicker and glide further. I notice in strong quarterly crosswinds I don't have sway like I used to.

I would recommend airtabs to anyone who wants to save fuel and increase vehicle stability.

Yours truly,

Ralph S.
Alberta, Canada

Aeroserve Technologies would like to present the following article.
Case Study 1 and 2 from the text below was used by Australasian Transport News in their August 2005 edition for an article called "Smooth Running, pages 79-81".
Australasian Transport Technologies Ltd., (ATT) is licensed by Aeroserve Technologies Ltd (ATL) of Carp Ontario Canada.
World wide, Airtab has been fitted on thousands of vehicles including straight trucks, recreational vehicles, pick up, cars, horse trailers, vans, semis, trailers (including doubles and triples). All users are making the same claims about stability, cleanliness and fuel savings. The Airtab has also been used on NASA wind tunnel walls and also on jet vehicles.
For more information please visit www.airtab.com.
Airtab Press Piece Australasian Transport News (ATN)
A product known as Airtab has been around the Australian Trucking scene for several years. They’re small plastic or vinyl vortex generators that fit around the trailing edge of a vehicle and claim to deal with the problem of rearward turbulence and parasitic drag.

The basic aerodynamic theory is this:

As a vehicle moves, air rushes into the space it just occupied. With the typical square and flat back of a truck or trailer, it can’t rush into that space smoothly and the problem gets worse as speed increases.

The result is turbulence, which creates drag and requires power and fuel to overcome. Any long haul operator would know of the problem which is evidenced by the turbulent mass of airborne water behind a truck in wet conditions and by the heavy build up of road grime that happens on the trailers back doors or panels.

Airtab is a product that claims to address this problem by creating a series of controlled swirls of air (vortices) behind the vehicle. These vortices smooth out the airflow and reduce the turbulence and drag.

The Airtab claim is that vehicle stability is enhanced, rearward visibility is improved in the wet, vehicle rears stay cleaner for longer and that fuel consumption is reduced.

Big claims, so we decided to speak with some long term Airtab users about their experiences.

Case 1:
Chris Binks does big kilometers. A driver with Ballarat Refrigerated Transport, Binks tows a B Double fridge van combination from Melbourne to North Queensland and Melbourne to Brisbane fortnightly and has been towing Airtab-fitted trailers since 2000. "When I first had these Airtabs fitted, I was pretty skeptical, but wanted to keep an open mind" says Binks. "I noticed a handling difference right from the beginning and as time went on, I also noticed an improvement in fuel consumption and trailer cleanliness. Airtabs had me impressed after the first few months but it was hard to firmly quantify the benefits".

When Airtab manufacturers, Australasian Transport Technologies heard from Chris of an upcoming replacement of trailers in July 2004, a trial proposal was formulated. "We agreed to run the new trailers without Airtabs for a couple of months and keep a thorough record of fuel consumption. We then fitted the Airtabs and ran for a further 3 months, again keeping a close eye on the fuel" says Binks.

"I have to say that I really noticed the change when I took delivery of the new Maxi Cubes and started running without the Airtabs on. I didn’t like it at all as I’d become used to the way the Airtabs made the trailers more stable on the road. The B trailer in particular seemed to wander that little bit more and the trailers were definitely not tracking behind the prime mover the way the old units fitted with the Airtabs used to. I also noticed that the build up of dirt and road grime in between the trailers and on the rear doors of the B trailer was far, far worse than I’d had for a long time."

As planned, Binks ran Townsville – Melbourne, Melbourne - Brisbane without Airtabs for the months of July and August 2004 covering 32,000 kilometers (19,872 miles). Average fuel consumption for the Freightliner Argosy with a 14l, 550HP Detroit engine over the period was 63.82 litres (16.8561 Gal.) per 100 kilometers (62.1 miles).

Airtabs were fitted to the vans by Maxitrans at the end of August 2004 and the units ran the same routes with the fuel data being very closely monitored. ATT and Binks monitored for a further three months covering 55,000 kilometres (34,155 miles). Average fuel consumption was down some 2.4% to 62.32 litres (16.46 Gal.) per 100 kilometres (62.1 miles).

"I wasn’t at all surprised by those results" says Binks. I was relieved to be back running with the Airtabs and noticed immediately the reduced effort in driving. The trailers weren’t "waddling", I wasn’t fighting the effect, especially in cross winds and I was spending far less time cleaning, particularly the B trailer fridge motor in the gap. I also asked a few blokes what they were feeling as they overtook. Sitting in behind me the airflow was smooth, when they came out to pass; some said it was like "hitting a brick wall" as they passed out of the Airtab vortices and into the dead air. You know, there’s also something happening here with tire wear. These trailers have over 200,000 kilometres (124,200 miles) on them now and the tires are still in really good shape. It’s to do with the stability improvement which I think may be reducing bounce and scuffing".

On these results, ATT calculates that the fuel savings over the 55,000 km (34,155 miles) were valued at about $1,180 assuming a diesel price of $1.20 per litre . At a price of $775 ($570.27 USD) for the Airtab B Double kit (plus fitting) the devices achieved payback at about 43,000 km (26,703 miles). Not bad at all at today’s fuel price and added safety benefits to boot!

Case 2:
Brisbane based NQX has also been impressed with the Airtab package of benefits and now has over 40 curtain sided trailers in the fleet fitted with the devices. "We fitted our first curtains with Airtab strips back in 2001" says NQX Operations Manager, Tony Brandt. "The concept of vortex generators seemed logical enough and we’re the sort of organisation that will try new innovations if the reasoning is sound."

"The big ticket advantages that we see are firstly the way the Airtabs tend to minimise the curtains billowing at speed which is an obvious aerodynamic problem. They also keep those rear panels and doors very clean which saves us time in the yard. Another significant advantage is the greater on road stability that is particularly delivered in cross winds and this has been consistent feedback from most drivers. Finally, rearward spray is far less of a problem in wet conditions with the Airtab fitted units. Our guys can see better what is happening behind them and people following enjoy greater visibility. It’s a clear safety improvement."

Brandt says that in the NQX system, with a large number of tow operators and trailers constantly being changed to different power units, it hasn’t yet been possible to get a definitive feel on the fuel consumption issue. "I wouldn’t be surprised if there’s an improvement here, but we just aren’t set up to get an accurate figure. With some trailers fitted and others not, we can’t yet tell in a definitive way."

That could well change over time as more new NQX equipment hits the road with Airtabs fitted by manufacturers as new trailers go into service. "We’ve specified Airtabs on all new long haul trailers for a while now including our triples in the Northern Territory and the new "Switfliner" concept vehicle we’ve recently developed. The safety benefits alone justify the relatively small initial outlay" he says.

Case 3:
Specialist fleet operator Displayco is a designer/manufacturer of display and advertising materials that handles its own distribution via a fleet of seven rigid pan techs, mainly on the Melbourne-Sydney and Sydney-Brisbane routes. The Displayco fleet, consisting of Hino, Isuzu and Mercedes units with fiberglass pans from 14 feet to 28 feet all now run with Airtabs after initial trials back in 2000.

Managing Director, Denis Walker says "these devices are now just a standard fitment as our fleet develops. Our trucks run a little heavier than the norm as we have tail lifts fitted, so we look for every efficiency enhancement we can get. Our first trials showed a fuel consumption improvement of 2.7% and that was enough for me to take the decision to fit-out our fleet there and then. But to be honest, now that we’ve used Airtabs for some years, the big improvement in stability at highway speeds, the better rearward visibility in the wet and the cleaner tail lifts would have been good enough reasons in themselves to take on these things." Walker can speak from experience. It’s not unusual for him to be behind the wheel of a Displayco van personally on the Hume or Pacific Highways. "It’s really quite a dramatic difference in handling" he says. "Cross winds in particular can really make driving our pans a tough task and reducing that turbulence at the rear makes the driving far more comfortable. I also like the way we can see clearly behind us in the wet instead of dealing with that swirling mass of grimy spray. I can’t understand why anyone wouldn’t fit Airtabs if they’re doing highway work. I look at them now as safety devices that also pay back real money".

Food for thought here for all truck operators it would seem. An outlay as little as $400 will buy a single hard-sided Airtab kit, sufficient to fit out one van. With fuel prices rocketing, we may well be seeing more these devices out on the highways before long.

Airtabs are available nationally in Australia through the Kenworth AllRig network of parts outlets.