Large remote-controlled aerobatics helicopters often use a belt drive to transmit power from the electric motors to the rotor shaft. These belt systems require toothed wheels to grip the belt and form a strong connection between components and the wheels are traditionally made from milled aluminum or molded plastic. These designs have several disadvantages, namely expense for aluminum and the inability to withstand high loads for plastic. Our goal is to develop a carbon-SMC belt wheel which would solve both problems with the traditional materials.
In this case we could take advantage of the strengths of carbon SMC construction once again. Due to the complex geometry the pressing tool has been produced with a wire eroding process. As the interlock does not allow any draft angle, a raw carbon SMC material was chosen that is capable of compensating for this effect. As an end result, we were able to reduce the weight by 39% and the cost by 51% with an annual quantity of 200 pieces.