Oh thanks! We've made small gliders and those butterflies with rubber bands, but I never thought that mode of operation went that far. It makes sense to use something that requires higher torque like clock mechanism to limit the speed of the blades/wings, the basic builds don't fly that well or for long precisely because the faster you spin (more twists) the less effective the angle of attack is, with gliders you need a somewhat precise alignment in terms of twists+launching speed in order for them to fly just ok!