"A piece of motorsport equipment doesn't need to be pretty, right?
Well it's different here at the Sultans of Sprint!"
–
Philipp Ludwig | Kraftstoffschmiede
Burn that rubber.
Two taps on the shoulder from behind, the sign that the tyre has reached the correct temperature.
In fact he can judge that from the color of the smoke by now.
We are at the starting line of another motorcycle drag race. My friend Philipp Ludwig runs his workshop Kraftstoffschmiede from a little town outside of Munich and is one of the founders of the European Motorcycle Drag Race Championship Sultans of Sprint. It all started years back when Frenchman Sébastien Lorentz brought a super low vintage BMW with a dust bin fairing, called the Lucky Cat, to the strip. It didn’t take long and racers around Europe brought their “cat killers” along to race Seb. Competition grew over the years to become what it is now. A bunch of creative, speed loving petrolheads with a huge passion for anything two-wheeled, customized, loud and fast in a straight line.
Concept.
Once the deal was sealed with BMW Motorrad and Phil got the go-ahead for building the 2019 Factory Racer, very soon a brand new R 1250 RS with a full Option 719 package rolled onto the ramp at Kraftstoffschmiede. It was quickly stripped down to a bare rolling chassis and engine in order to lay out a plan for the build.
This is where I came in, Man & the Machines Design. “Designing a piece of motorsport equipment requires industrial design in its purest form.” As a matter of fact, there is no need for it to be pretty as long as it performs, right? Well, this isn’t exactly the case at the Sultans. This bike had to be an absolute eye catcher, an extrovert one off rocket ship, an ambassador for BMW Motorrad’s sporty brand identity and lifestyle orientation.
Phil had a clear idea of the bike’s concept. It had to have the same perfect weight distribution and ergonomics of his other BMW based sprint bike HERCULES and he wanted a hint of a bagger flavour supported by a massive front wheel. A classic land speed record racer inspired fairing was in the back of his mind too incorporating a largely covered front wheel. Not your usual setup for a sprint bike.
Design.
With those requirements in mind, I started to sketch the motorcycle. All the optical weight needed to be shifted forward, literally hugging the big front wheel. The tail section ends forward of the rear axle, giving an impression of an extended swingarm. That super wide boxer engine was incorporated into the design too and the cylinders partially covered, giving the bike a wide stance reminiscent of a manta ray. ACHILLES not only had to be fast but also look fast, so an aggressive stance and the main body lines pointing down towards the drag strip in front create the appearance of being fast even when standing still. Flowing surfaces and sharp lines describe the seat monocoque and the aerodynamic front fairing.
Not exactly the style Phil had envisioned at the beginning of the project, therefore surprising that it brought a sparkle to his eye straight away and he fell in love with the design. Performance features such as open K&N air filters, side air ducts and a quick release filler cap round it off.
In parallel to the 2D design phase, Phil was working on the hardware. Together with his trusted metal shaper Franz he fabricated an aluminium fuel cell and an all aluminium tail section incorporating the Nitrous Oxide bottle and the vehicle’s motor management.
Front and rear suspension are custom made fully adjustable items by German manufacturer Wilbers Suspension and have been optimized for maximum traction. The fork is held in place by a CNC machined set of Phil’s own designed, cranked triple trees with an additional 50mm offset for a longer wheelbase and ideal weight distribution.
The foot position on the custom made rearsets is very far back and close to the center of the rear wheel. This way the rider’s weight shifts back at the start and transfers extra pressure onto the back wheel for maximum grip.
A full custom exhaust system was made in house at Hattech in a day. The full stainless steel twin mufflers and headers carry the most beautiful welds and look the part with their ground-hugging position. And finally Kineo sent over a set off custom built 3,5x19 and 5,5x17 spoked rims wrapped in sticky Shinko rubber.
Throughout the entire build we were bouncing our ideas back and forth. All issues on Achilles were solved with a very healthy compromise between design and engineering, Phil giving very valuable design input and learning about industrial design and the motorcycle design process, while I learned all about racing requirements and hard business calculation.
Once we had agreed on a final design sketch and all hardware like fork, swing arm, wheels, tank and handlebars were in place, the bike went through a complete 3D scan. All digital modeling, form finding and construction was done by KKN Engineering. The initial plan for producing the fairing and seat monocoque using a unique basalt fibre process would have messed up the business plan badly, so plan B came into action and monocoque, the first fairing for the black and grey design and all structural assembly elements were 3D printed by specialist Creabis and reinforced with carbon fibre. The second fairing for the white BMW ///M inspired design was printed by FKM Laser Sintering.
EU5 emission regulations have become very present in the motorcycle world, which meant countless sleepless nights for Phil, optimizing the engine setup on many dyno runs to perform like a real drag bike should. Further a closer gear ratio taken from an R 1250 GS helps with the torque figures.
"Building Achilles in six months
was a huge challenge. Working through countless nights while trying to maintain
a healthy work life balance."
–
Philipp Ludwig | Kraftstoffschmiede
A complete one-off racing prototype with a perfect finish. All of this was only possible because of our network of partners in the industry, especially BMW Motorrad, KKN Engineering, Wilbers Suspension, Hattech Exhausts, Creabis, Ilmberger Carbon Parts, FKM Laser Sintering and Nitrous Express, just to name a few.
