Flintstones
Concept
A compact python / push trike for 3 small persons. Small enough to fit inside a MINI Cooper.
Design
Experimental 30 degrees pivot, ring frame, low-back seat / bench
Ring frame allows room for rear passenger legs pushing on the ground, and resting when not.
Build
The ring frame is made of two 2" dia U-shaped sides of the futon sofa bed, welded together to make a very strong frame.
16in front wheels w/ extreme 30deg pivot requires 2 bungee cords to hold it up
16in rear wheels came from are quick release from jogging stroller
Low seat backs allow the front seat and rear bench to be closed together. Rider and passengers lean on each other for back support, in 1:1 or 1:2 layout.
Test
The bungee cords do a decent job of contraining the wheels from flopping at rest or speed. The frame is really strong and light, so the trike is fast at sprint (single gear). 30 deg pivot is quite ridable in a trike form.
The seat / bench can be a little uncomfortable if the rider & passenger(s) don't fit together well.
Very popular among small folks...
Fits inside a minivan for a day trip (video log)
Pretty good traction / stability on gravel surface (video log)
Training
Not much other beyond pedal steer
Links
Vi, Futon Express, Bango, Flintstones, μPython, Mini Python, Guinea Pig, Bipolar, FP02, FS24P