pic: Planetary Gearset
 

in an automatic transmission like this in a car, there are clutch mechanisms, called bands, that hold one set of gears still, to get the ratio you want to the output

and dont forget, the torque converter in a car is not only a slipping clutch, it is also a form of hydralic CVT itself (its like a backwards CVT - the motor can vary over a range of rpms while the drive wheels are at a constant speed)

You can get more HP out of an automatic transmission off the line, than you can from a standard one (with a clutch) because the auto can rev up to its optimum RPM

very similar to the problem we face with electic motors - to get the most HP they have to be spinning at the midpoint of their RPM range

Yes, I've been thinking about the bands, there are some possibilities of building a one way clutch, and something I'm working on that I call a limited slipping clutch. It works on the idea that the clutch holds the part still until a certain amount of force is applied, then it starts to slip and and all heck breaks loose, not that this clutch will probably be a one time use device. The other big issue I see at this time is the fact that in an automatic transmission there are pneumatic "breaks". They are what hold the gears in the gearset to get the different ratios. I need to find a way to make something like that to make an efficient gearset.
Ivey

Re: pic: Planetary Gearset
 

there aren't pneumatics in any slushbox that I'm aware of--it's called a slushbox precisely because it's hydraulic (well ok, so no it isn't... that's because of the aforementioned power-sucking torque converter. Come to think of it, horsepower isn't the only thing it sucks...).