Today I finally was able to install the key assembly in the power train for the new tandem. This assembly is a jack shaft that allows the blending of power from the rider and the auxiliary electric motor. That is the rider can power the wheel with no auxiliary power. The auxiliary motor can power the wheel and the rider can coast. Finally both can power the wheel at the same time.
At the same time the shaft itself functions as the pivot for the rear wheel suspension. This is good because the chains don’t vary in length as the suspension flexes.

The next task is to configure the front wheel drive. It will be pedal power only. The tricky part will be that the pedals will remain fixed to the frame and the chain will have to bend with the steering. I have ridden another person’s bicycle with a bending chain drive so I know it will work. I just have to position some idlers at the perfect point.
It was exasperating trying to compete this task today. The rainy season has started in Hillsboro where we are staying. We would get a delightful “sun break” and I would unload the bicycles and start working on the shaft with the lathe. About then the light would go away and a cold rain squall would descend on us. I would quickly return the bicycles to the trailer, lock up and retreat to the warmth of the coach. Half an hour later the sun would be back. Out comes the bicycles again and I would get back to work. Repeat the scenario several times.
The other complication occurred when I started to drill the setscrew pilot holes in the collar that locks the shaft in place. I wanted three equally spaced setscrews in the collar. I have the perfect tool, a dividing engine that allows you to rotate the part with exact precision. I dug it out of the tool chest and was horrified to see that it had rusted in the damp air. I spent about two hours disassembling the tool and polishing each part and carefully oiling and reassembling it. When compete I mounted the collar and drilled three pilot holes at exactly 120 degrees from each other.
We need to get out of this damp weather and back to the warm dry part of the country.
These years I have written extensively about “Path” the green dragon. This is our recumbent tandem bicycle. I designed and built “Path” back in 2001 and he has been our trusty steed these ten years and 13,701 miles. Path replaced our regular garden variety upright tandem named “The Purple People Eater,” (because it is purple, of course.)” Purple” has 8,428 miles on his odometer. Last week “Purple” came out of retirement and will replace “Path” as our ride of choice.
What I need to explain is that “Path” is harder to balance on. There are two reasons. First: we are closer to the ground so you have to correct for errors in balance quickly. Second: because my feet swing with the whole front end of the bicycle to steer, it takes more strength and coordination to ride a nice straight path at the edge of traffic. Over the past year my balance has been deteriorating and it now takes most of the lane to keep my balance. In April of this year my diagnosis was confirmed, I am in the early stages of Parkinson’s disease.
The new tandem will be designed for Judy to be the captain. I will become the stoker. As soon as we can finish up the new tandem we will probably retire “Purple” again. In the meantime I expect to hear “Shift!” from the back seat every time I start lugging the cadence, and I will have to remember to yell “bump” when a chuck hole rears up.