This is a prototype of a simple Torque Convertor for a toy racer or other small mechanical device that would profit from a smooth take-off. The thing must be filled with oil in order to function and it needs to be glued so the oil remains inside. It works well at anything between 200rpm to 1500 rpm. It's output is about 7:1. It is off course quite energy-inefficient, but you probably figured that out already. :) Any input to improve the design is welcome ! I created this object with Sketch Up. It has to be filled with thin oil and glued in order to function. The small rotor is a "pump" and needs to be hooked up to a motor. The large rotor needs to be connected to a set of gears. The thing has holes in it for 4mm rods. update : I printed the prototype and I glued axles to it. I then filled it with thin oil, but that doesn't work very well (the oil leaks out pretty quickly), so I filled it with Castrol EPX Axle fluid 80W-90. Moving the pump rotor, immediately forces the output rotor to rotate, so that's a good sign. I'm waiting for the thing to dry properly and then I will attach an engine to it. :) update: attaching an engine to the thing, proved more difficult than I first imagined. I hadn't topped the thing out with oil before glueing it shut, so it wasn't functioning properly. Low RPM's were fine, but high RPM's caused stalling of the output rotor. Further investigation led me to think that there was insufficient oil in the housing and the 80W-90 was to thick. I drilled a hole in the housing and added thinner oil. I closed the hole with a screw and voila : It works ! I will look into a redesign of the thing so it can be filled up easily. You should be aware that the current design is leaky as hell and needs a refill after about 10 minutes of high RPM use. I'm still looking into a solution. Grtz Dustin