About 1995 or so I was at the Sun Fun air show in Lakeland Florida and saw my first two wheeled bents. They were built by the Rans aircaft folks but they wouldn't let you ride them at the air show. I had the bug and soon after returning home from the air show I hacked some old bikes that I had into this long wheelbase bent.
It was difficult starting from a stopped position... took a two acre field to turn around... and the frame was big time flexible. I later added a weed eater motor that was just a friction drive against the rear tire. Put a lot of miles on that thing.
Moped Bent
One day I upon arriving at work the guy parked besdie me had just arrived as well and had what was left of an old moped in the back of his station wagon. He gave it to me to use in what would become a mockup of a possible stretched bent moped. The engine was toast but the drive train was unlike any I had seen but has become fairly common on most all moped now and even on some larger bikes. The whole engine, drivetrain, rear wheel, was a complete module. and would be easy to hack into some sort of stretch moped or even a three wheel powered trike. The ideas for further development of this drivetrain are awaiting acqusition of a running drivetrain.
The Thunderbolt Files
I somehow stumbled onto the Human Powered Vehicle website and the ThunderBolt. There was a ton of information regarding building this trike which was pretty high tech. It had a heat treated aluminum frame and detailed information about steering system geometry and setup. Within hours of finding that site I had a rolling chassis of my first three wheeled bent.
The Rolling Chassis
I already had the wheels that I used on the front of this trike and that's what made it a fairly quick build, at least to the rolling stage. These were actually moped wheels that were off a Tierra TA ultralight that I had flown till the sails were ragged. Interestingly I only had a steering arm attached to one wheel and the other wheel would follow at low speeds, which at first was just coasting down an incline from my shop out to the street.
Flex Suspension
The rear section which was hacked off a twenty inch bike was attached via a pivot and the plan was to let the seat, which was laminated from 1/8 door skin plywood, flex and allow some movement in the rear end. The seat ended up way too stiff for that too work.
Trike 1 Version 1
This is how the finished product ended up. I was definitely hooked on Recumbent Trikes. It was certainly on the heavy side but was a blast to ride. Kinda like a go cart except you have to pedal. I used body english to keep the thing upright but I let a friend ride it who promptly rolled it. I started modifications which would become Recumbent Stage 2.
Lowered Front End
Actually... lowering the front end was much easier than I had anticipated. This was because the king pins could just be swapped from one side to the other and turned upside down to effectively lower the about 2 to 3 inches. I usually like to braze as apposed to weld some of these parts. Brazing is relatively easy makes nice looking gold welds and can easily be reheated and adjusted as is there is often a need for this at the ShadeTree.
An Ongoing Testbed
The wooden seat idea didnt last too long til I went with a more conventional seat/frame. I used thin wall conduit for this 3/4 inch for the seat and 1/2 inch for the braces in the back. The main frame was so beefy I did not need much strength in the seat parts. Conduit is cheap and easy to bend and handy for prototyping.
The Rear End
I still had the pivot point on the rear end at this point. Next phase was to eliminate some of those unused parts on the rear end. In the process I cut a wrong piece of tubing on the rear end and ended up going with a different rear end with a 26 inch rear wheel.
New Rear 2
This phase included a 26 inch rear end and eliminated most of the unneeded pieces.
Vesion 1 End of Life
This is about how the trike looked near the end of its life. I was transporting it on a trailer when it blew off and went end over end for while. I think this is a 24 inch rear wheel.... the 26 was pretty ragged and kinda flimsy. The 24 was salvaged from a mountain bike and more beefy..... also was experimenting with under seat steering (a la greenspeed) near the end.
New Bent in Town
Following the demise of the ShadeTreeBent l the final version... I was fortunate enough to acquire this Catrike Speed. Light and quick but a little squirrelly at high speed. The king pin bearing and the rod end bearings were made out of some funky plastic the refuses to be lubed. They have a sticky quality that is detrimental to the steering. This stickyness prevents the bike from self steering. With no steering input the steering should try to return to center. It also makes small corrections to steering difficult as you must overcome the friction and it makes over correction a problem. I've considered and probably will eventually replace the king pin bearings with some made of delrin or high density polyethylene... they are both naturally slick.
