Light and fast - a new concept in crash tenders
Published: 01 January, 2009
When Terberg Techniek turned its expertise to the design of an airport firefighting crash tender, it started with no preconceptions. The result is a revolutionary ARFF vehicle that takes performance standards to a new level.
Dutch chassis builder Terberg Techniek, GRP body specialist Plastisol, and German vehicle body builder Lentner, have combined to bring a revolutionary new concept to the airport firefighting market in the shape of the new Avenger crash tender. This airport firefighting vehicle carries a special subframe specifically designed for crash tenders, plus a hydraulic cross-linked wheel suspension system, providing high manoeuvrability, good stability on the road surface and a tiny turning radius.
IFJ visited Terberg Techniek in the Dutch town of Ijsselstein, and met Erik van Wilsum, in charge of commercial activities, and Guido Schoeman in charge of technical development for the company. Van Wilsum explained that Terberg Techniek is a speciality vehicle builder and modifier, part of a large 125-year old truck manufacturing organisation called Terberg, best known for its refuse collection vehicles and army trucks.
Terberg Techniek, however, specialises in one-off speciality vehicle solutions for defence, police, and now also airport fire services. Apart from manufacturing vehicles from scratch, the company also specialises in body and chassis modification, repairs and servicing. “We have been involved in several high-profile vehicle building and modification projects. One of them involved the transportation system for the second set of stairs for the Ariane Rocket, the missile built by the European Union for space exploration. The fire industry is a new market for us, and this enabled us to look at the crash tender without any preconceptions, and as a vehicle concept from a completely new perspective,” he explains.
Body specialist Plastisol approached Terberg Techniek for its proven expertise in vehicle building. According to Van Wilsum, the crash tender market has fixed too much attention on the bodywork in the past, and not enough on the subframe. “The development of the Avenger was born out of performance requirements, and right now we are waiting for the market to respond so we can see if ARFF brigades have a requirement for the extra quality we can offer with the Avenger.”
It is safe to say that a crash tender’s performance requirements in combination with compliancy with regulations probably pose one of the most difficult design challenges for a vehicle builder. Conventional crash tenders are built on a leaf suspension, which is suitable for normal fire vehicles, explains Van Wilsum, but these have not been designed with ARFF requirements in mind. “Conventional chassis have not been developed to deal with the excessive braking, high acceleration and deceleration rates of crash tenders. Moreover these vehicles carry around 12,000 litres of water and 1,440 litres of foam whilst travelling over uneven terrain, and all of this has to happen within the maximum response time of the three minutes stated in ICAO regulations.” Terberg Techniek therefore developed a hydraulic pneumatic suspension system, with separate circuits for the front and the rear axles. As a result, a special pump is installed in the engine, driven by a multi grove belt. The oil pump fills up an accumulator, and this provides the necessary oil for the system.
To establish the high stability of the vehicle, (so it can turn at high speed without compromising driver comfort or in the worst scenario capsizing), the cylinders of the suspension system are cross-linked from the left to the right. The long stroke of the cylinders provides an extremely steady grip of ground surface, which in effect gives even more grip than an independent suspension would.
Additionally, because the need for speed on a crash tender is highest when travelling fully loaded with water, the company implemented an electronic height-levelling device that automatically adjusts to speed and the type of terrain, giving the appliance an optimal pay-load in all situations.
As the sides of the runway are slopes, a water-levelling device enables the crash tender to compensate both sides of the wheelbase – left and right – on a slope, so the tender will always be in stable position on uneven terrain.
The special space frame superstructure, which forms the base of the chassis, is designed in such a manner that the torsion on the vehicle is extremely low. Van Wilsum explains: “Together with the material used by Plastisol, called GRP (Glass Re-enforced Polyester), this construction is extremely light, and easy to put together, and this increases the vehicle’s lifetime considerably. The only thing that the bodybuilder has to be more considerate about is the placement of tubes and pipe work on the subframe.”
To provide maintenance access, Plastisol has added its own expertise to the vehicle in the shape of a two-piece GRP engine cover, when usually the engine cover is a one-piece element.
The gross vehicle weight of this 6x6 vehicle is 42 tonnes, and the vehicle can handle 14 tonnes on each axle. Clients can choose between a Euro 3 or Tier 1 engine, and its top speed is a 125 kph, with a 27 m turning circle.
The Avenger meets the requirements of NFPA 414 2007 (Standard for Aircraft Rescue and Fire-Fighting Vehicles) and ICAO (Doc 9137-AN/898). Van Wilsum adds that the vehicle has been designed for operation between -32 0C up to 48 0C, but that the temperature range can be extended by adding several arctic or tropical packages.
In December 2008, partner Lentner delivered the second Avenger to Lodz Airport in Poland, while earlier in the year another Avenger was delivered to Bydgoszcz Airport, also in Poland. Terberg and the other companies involved are now testing the water to see how this revolutionary new vehicle will be received. At the same time, Terberg is in the process of developing a Euro 5 version. “We are looking at a twin engine version, as the power requirements are getting too large for one engine.” Currently, the Avenger is available in three different axle configurations, 4x4, 6x6 and 8x8.