I've finally seen a Landrider in person. It does look interesting, and if I'm lucky I'll get a chance to stick a motor on that drivetrain to see what happens.
If I was just pedalling it, I would take a while to get used to the autoshifting--I see why they are not popular with regular cyclists; it's kind of unpredictable at first and throws you off cadence.
But with a motor doing the real work, and me just pedalling to help, the sudden changes in torque would not be a big deal, especially if my cranks were freewheeled from the motor.
Some thoughts on the 3speed hubs and braking below, originally posted in another thread today but figure they belong here too:
I wanted to use the coaster brake feature of a pair of Sachs 3speeds Spinningmagnets sent me, but haven't figured out a good way to do it. I'd either need contactors to reverse the motor connections of my brushed motors, or a full-bridge controller. Neither one is particularly appealing, though the controller solution would require less engineering at my end, since I would not have to deal with spindown, etc.--it would do that for me with just a signal on the Reverse input line (from the brake lever in this case).
Assuming of course that the controller was well-engineered, rather than leaving it up to the user to ensure all conditions necessary for reverse were already met before engaging it.
I would still need a little electronics outside the controller though. A little circuit that cuts off the regular throttle input, and puts it's own throttle control input instead, immediately after the Reverse input is triggered by braking. That way the motor is not accidentally triggered full blast in reverse, breaking stuff inside the hub, but is held in reversed position by minimal throttle until braking is stopped.
That gives only full braking. If I wanted to modulate the braking force, I would need to monitor the brake lever position, and use that as the throttle input instead of a fixed low-% of throttle.
It gets complicated pretty quick, so I decided it is easier to figure out how to mount disc brakes onto the hubs, or use rim brakes, than it is to deal with the coaster brake by motor power.
I did have an alternate mechanical braking option using a rod or cable activated manually, but it would require rotating the entire hub's axle/torque-arm forward while maintaining it's anchor to the frame to prevent spinout. I don't feel confident enough in the ways I have to make the parts to be sure it wouldn't fail under use, compared to a simple fixed dropout as it was intended for.
Since a power or controller or motor failure would also cause zero braking ability, that was a further motivation to skip the motor-activated coaster idea and go right to the fully-mechanical rim or disc brakes, plus a mechanical brake on the pedal-only wheel.