Rotor module
Swimmer
The idea was to create a simple object that produces electricity: a swimming, mobile power station, consisting of as few, easy-to-get industrially manufactured components as possible.
Why a tractor tire tube?
The tractor tire is a familiar object from childhood, especially in combination with water. It can be handled easily and has an extremely high load capacity. Furthermore, it is a perfect carrier because the mechanics can be placed at its center. The tube is very robust, and even if it bursts, it can be fixed quickly – almost everyone in the world knows how.
A basic problem was porous rubber caused by UV radiation. Considering series production, we tested several options for UV stability; a rubber coating turned out to be the best solution. We also wrapped an elastic belt around the tube to protect it against flotsam.
Did you think about another floating body?
Yes. We added a second floating body made of foam, which prevents the Rotor from sinking if the tire gets damaged. We experimented with PET bottles and water containers, but foam is the simplest solution.
We also built a second prototype with a boat shape for better lift and flow; however, the additional weight and production costs were disadvantageous.
What was the decision and why?
We wanted to use only materials that can be easily repaired or recycled all over the world – that’s why we decided against a plastic boat shape.
Another design uses steel drums: it can handle the weight and is nearly indestructible thanks to its reinforcement. The drums can also cover the mechanics and are waterproof. The problems are venting, cooling and condensation.
We also tested a combination of tire and boat shape in front of it. It works well until too much water spills over and the Rotor submerges.
The best solution is the tire: it can be folded and simply inflated on site, which also makes it perfect for shipping. We tested different tires and chose the one with the best price-performance ratio.
What could be improved?
We were testing a light-stable belt that gives the tire more stability and protects it from damage and UV radiation. A solid, light shell around the tire would be ideal, but is difficult to make.
Variants we tested
Tractor tire
Steel drums
