Hang On, Lean Steering!
I'm wondering if building a conventional tadpole trike, with "sports car" steering geometry is the right way to go. For the last few days I've been trying to reverse engineer the lean steering of an AR-3 trike, yeah, maybe for shits and giggles, but seeing the basic frame parts "move!" Wow! Update: I'm now seriously considering this steering pattern for my trike build. A decision that pretty much throws out everything but the parts list. Update 2: I'm sold! This is it.
Not shown is how to lean the front wheels, but that's just horizontal kingpins at the end of the transverse beam and tie rods from the chassis to an upright wheel boss at each end of the transverse beam that pivots on the horizontal kingpins. In theory. Still some work to do, but I've cracked it! This is parametric, too. I enter a turning angle and it calculates the pitch of the transverse beam in order for it to stay horizontal.
I might be making some design changes before I build. This type of steering is more bike-like, and can even be steered simply by shifting body weight - look, ma, no hands! It's also able to be ridden more aggressively into corners and can make somewhat tighter turns than an ackerman steering conventional trike. It's also potentially much simpler construction. Everything is right angles and mitres on this, there's no zero cross to have precicely right, no ackeman angles to make steering brackets for and to toe-in to spend hours tuning.
Here's the older, bare bones GIF
And here are some static elevations to show how aggressive this design can get.
Viewed low from the front, you can see how "cooked" cornering looks.