The KTM X-BOW is the first standard volume production vehicle to boast a monocoque made completely from composite carbon fibre material – a trailblazing and pioneering technology, previously reserved exclusively for racing cars or supercars manufactured in small volumes. However, the high-strength safety cell is not the only innovation to be found in the first four-wheeled vehicle from KTM.
The safety cell: high-strength carbon monocoque
Four layers of carbon fibre, epoxy resin, elaborate craftsmanship and autoclave technology – all come together to produce the dual-wall, two-part X-BOW carbon fibre monocoque weighing only 80 kilograms. With this innovative structure KTM is setting new standards, not only in automobile series production, but also in automotive safety standards.
There are very good reasons behind carbon fibre monocoques being employed over the past decades as the safety net in many top forms of racing, particularly in Formula 1. Together with Dallara, the motorsport specialist from Italy, the experts from KTM Technologies worked on the serial development. has long been regarded as an expert in the development of carbon technology. The expertise of the Wethje Group in southern Germany is exploited for production of the ‘tubs’. Wethje is one of Europe’s most experienced specialists in carbon components, supplying many renowned car manufacturers as well as Formula 1 and touring car racing teams.
The two-seater, carbon-composite monocoque developed for the X-BOW is a solid supporting structure, embodying a high degree of safety in its construction – but it only weighs approximately 80 kilograms. The carbon fibre design allows the combination of extremely low weight with an unbelievably high level of stiffness. The X-BOW provides 35,000 Nm/o of torsional rigidity – double the standard value for open-top vehicles, such as convertibles, of conventional construction. The monocoque is supplemented by a carbon-sandwich crash-box at the front of the vehicle, which complies with the stringent FIA safety regulations for FIA-GT and Formula 3, as proven in the crash tests conducted voluntarily by KTM. In these tests, the crash-box/monocoque combination is crashed at 60 km/h into a non-deformable concrete wall. After impact, the monocoque itself has to remain completely undamaged, while the predetermined limits for head and neck loads on the dummy may not be exceeded. In the event of rollover, the aluminium or steel roll bars integrated into the monocoque ensure optimum protection – they can withstand loads of up to 2.5 respectively 7 times the weight of the vehicle.
In addition, driver and passenger are each protected by a four-point safety harness, as used in motor racing, with an upgraded five-point or six-point harness available as an option. The standard lap and shoulder belts are adjustable individually and incorporate an anti-submarining system supplied by Schroth. Of particular importance for the driver, deformable elements are integrated into both the steering wheel and the steering column.
KTM Technologies
The development of the KTM X-BOW chassis in revolutionary carbon-composite technology is a milestone in the history of the company KTM Technologies GmbH situated in Anif near Salzburg (Austria). However the portfolio of businesses of the company which belongs to KTM Power Sports AG is engineering on the highest level. The strength of the company of some 20 employees headed by Peter Martin is the extensive know-how in the areas of vehicle design, lightweight construction and composite materials, especially the high-performance carbon composites. The engineers at KTM Technologies know the possibilities and understand the relationship with the futuristic but still complex fiber composite technology. They have much practical experience and understand what matters. They constantly strive for technically sophisticated and economic solutions and are therefore always at the cutting edge of state of the art technology.
The range of services covers the entire development process, with emphasis on concept and process development, simulation and on future series production. There is a very strong relationship to actual practice based on experience in the fields of manufacturing processes, the building of prototypes and serial production. Well-known companies such as Volkswagen or Adidas are the customers. Reference projects include the already mentioned KTM X-BOW but also the "2-3-4" electric vehicle, which were both realized together with associate companies KTM Sportmotorcycle AG and Kiska GmbH.
The vision of KTM Technologies is to assume a leading role as an engineer service provider for carbon composites in Europe. And the chances for that are quite positive: lightweight construction is currently the biggest trend in the automotive industry, because less vehicle mass means a lower fuel consumption, as well as more performance and/or range – of which the KTM X-BOW is an impressive example. The reasons for this trend are on the one hand the legal requirements for reduction of CO2 emissions, and on the other the trend towards electric drive systems.
It clearly emerges that in addition to steel and aluminum, more fiber-reinforced plastics (GFRP, CFRP) will be used in the future. Finally, composite materials have a weight saving of about 30% when compared to aluminum and about 50% with steel. Some vehicle manufacturers are currently developing new generations of vehicles that are fundamentally based on these materials, such as, for example, the low-energy vehicle "XL1" by Volkswagen or the “Megacity Vehicle” by BMW. In premium and sports vehicles, CFRP has already been firmly in place for structural applications for some years, thus the X-BOW was worldwide the first in-series and homologated vehicle produced with a carbon chassis and monocoque.
