The Hyperdrive connects the pilots' pedals to the front and back wheels, creating all wheel drive. With all the wheels finally back on the ground and the front differential secured, it was time to reconnect everything to the Hyperdrive.
For the front wheels, I just had to run a chain from the differential, but the shortest path between the two sprockets ran into the aluminum frame in two places. Avoiding this required adding two idler sprockets to redirect the chain's path. I used what I call lollipop standoffs--collars with a tapped hole on the side so they could be mounted on the end of a bolt or threaded rod. To redirect around the first obstacle, I mounted lollipops on the same threaded rods that support the canopy.
The second idler had to be lower than the back of the new differential frame. I first thought I could just mount lollipops on long threaded rods, but I was worried that torque in the chains would bend the lengthy rods. Instead, I took advantage of the bolts that secured the rear of the differential frame. I swapped them out with slightly longer threaded rods and mounted lollipops on the end of them.
After I secured the lower idler sprocket, I re-ran the front chain.
Last year, we tried to make a recumbent setup work. I thought it would be more fun. It wasn't. It turned out to be harder to pedal and the forward location of the pedals repeatedly interfered with the placement of mechanics at the front. It was also hard to get into the seat. This time around, we decided to use traditional bike frames. Not only can you use body weight to help turn the pedals, but it also moved the bike mechanics out of the way.
That, however, also shifted the rear derailleurs further back. And that now interfered with the rear chain's idler sprocket. The placement of that idler wasn't critical. It just needed to keep the chain out of the way, so I moved it down a few inches using lollipops with longer threaded rods.
The lollipop's versatility is the coolest thing about them to me. I used them all over the Falcon's main truss.
To complete the drivetrain, I then had to connect the rear derailleurs to the Hyperdrive. This was the hardest task of this job. Our bike frames were rescued from the scrap pile and are not the same. The copilot bike is smaller than the pilot frame, but we still needed the rear axles to line up with each other. Luckily, lifting the front of the copilot frame also rotated the rear enough to line up the two axles. I quickly designed and fabricated a bracket to hold the front of the copilot frame at the correct height.
The axles were now lined up vertically, but there was still a problem. There was still a two-inch difference between them, horizontally. Fixing this wasn't too hard. The derailleurs are held in place with custom brackets that I had previously designed and printed in plastic. To fix the discrepancy, I modified the brackets to move the pilot side forward one inch and the copilot side back one inch, then reprinted the updated brackets.
After replacing the brackets, the last thing to do was support the shaft between the bike frames–a perfect job for lollipop standoffs! For these, I made special ones on the CNC mill that could hold bronze bearings.
Then I hung the shaft, aligned the ends with the bike frame axles, and added one more idler sprocket before running the last chain to the Hyperdrive.
With the Hyperdrive restored, the Falcon could roll again. But we still had to make sure we could stop and turn before we could safely run a road test. That glory is next.
