I'm trying to design a single wheel trailer for my underpowered VW, much like this one.
Unlike a conventional trailer, it is attached to the car at two points. To prevent the wheel from dragging, it has a swivelling mechanism. Those are hard to come by, so I'm going to build one myself.
I'm not a mechanical engineer by trade, so the questions I have are probably quite basic:
With caster wheel wobble in mind, should the wheel swivel freely, or is some friction desirable?
What kind of bearings should be used for the swivel point? There is definitely an axial load, but is the radial load considerable?
What would be the most effective geometry? How much trail/rake? Is this something I just have to experiment with?