Control. Control. You Must Learn Control!

 We've been trying to get to our first v3 road test for a month. Timing and complications have drawn out the effort so far. We've installed the new front suspension, remounted the front tires, and reconnected all the inputs and outputs to the Hyperdrive (the main drivetrain).  We only needed to finalize steering and connect the brakes to get to our first road test. Without them, the Falcon would be more runaway train than racecar.

I Brake for Kinetic Sculptures

We use bicycle brake discs and calipers on the Falcon. They are meant to install only on the right side of a bike, so using them on the left side of the sculpture created placement issues. We dealt with this last year by mounting one caliper behind the tire and the other in front of the tire. The new suspension required that both calipers be located behind the wheels. I thought I would need to make a special bracket for the left side wheel, but it dawned on me that I could actually still use the same bracket...if I installed it upside down. Both calipers were behind the tire, the left side below the axle and the right side above it.

To solve our race killing problem from last year, we had added a lip to the outside of the plates to keep the bearings from squeezing out. 

This made the plates thicker overall and moved the calipers too close to the brake disc. I thinned the mounting tab to move the caliper inward a bit and aligned the calipers with the brakes discs.

I originally wanted to be able to activate all the brake calipers using a single handlebar brake. As with everything else on this beast, doing this required some engineering. I designed and fabricated a small manifold that would tie all the brake lines into a common bar that slid back and forth in a slot. 

I then attached the brake line for the handle to the common bar in the manifold, looping the cable tightly enough so that squeezing the brake handle would pull the bar back, which would then pull on the caliper arms and activate all the brakes simultaneously. 

This did not work at all. There was not enough leverage at the handle to fully activate the brakes. I went back to the central brake lever idea from last year, so we could get testing. 

Need More Direction

We could now stop and that was very important! Next, we needed steering. My steering schemes had not worked very well so far. I first tried a vertical swing arm. It was way too short and did not generate enough force to turn the wheels without great difficulty. I switched to a horizontal swing arm for the second attempt. It worked better, but not by much. I tried getting more leverage by using a longer steering arm, but to do that, I had to reposition the steering arm so it swung in clockwise, from the outside. However, that reversed everything--pulling left steered right and vice versa. I had to install gears to reverse the direction, but that system was never stiff enough to be effective.

In the latest design, I kept the same basic idea from the second attempt, except the gears. We also switched from a steering wheel back to bicycle handlebars. Handlebars made more sense since we were using full bike frames for the pilots. Turning the handlebars would spin a horizontal swing arm that would then push/pull an arm attached to the front wheel (the pitman arm) and turn it in the correct direction. I converted the front fork of the new bike frame into a new steering column, cutting off the legs of the fork and pinning a 3/4 inch shaft to the remaining structure.

The bike's head tube secured the steering column at one end, but the bottom also needed to be held in place. I brought back the support bar that I had used with the previous steering scheme. The installed support bar was not quite in the right spot to receive the steering column pivot point, so I designed and fabricated a ledge plate to brace the steering column at the correct location. 

After attaching the swing arm to the steering column, I just needed to connect it to the pitman arm attached to the wheel. This was the final design challenge around steering. The wheels were capable of dropping almost 4 inches in relation to the steering swing arm. I needed something that would not only transfer the turning force of steering arm to the wheel, but also slide up and down somehow. 

After a few iterations, I settled on a hinged, C-shaped transition arm. I made the arms using the Tormach and then welded all the pieces together.

I mounted the transition arm onto a long piece of threaded rod and connected it to a slot in the pitman arm using a long hex bolt. 

The pitman arm now slides down along the long bolt, allowing us to turn regardless of the front end's height. And now that we could roll, stop, and turn, we were finally ready to road test version 3. I hoped the tests would not reveal any further unforeseen issues, but given our testing history I expected something would happen. 

For the Glory! 

Rudy September 09, 2025

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I Need You To Talk To The Falcon...Find Out What's Wrong With The Hyperdrive

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.

After installing the bracket on the chassis, I used a U-bolt to secure the bike frame to the bracket.

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. 

Rudy August 19, 2025

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You’ve Deactivated My Primary Motivator!

We had very little time to bask in the glory of the new suspension. Getting to our first road test of the year still required finishing the new steering, reattaching the brakes, and tying all the wheels and the pedals back into the Hyperdrive. I concentrated on the drivetrain first. 

To reattach the front wheels to the Hyperdrive, the differential had to be remounted. 

The previous two versions of the differential supports were inadequate. The first was very difficult to keep aligned and the second was part of a heavy steel box beam. For version three, my initial idea was to attach the differential to the end of a free-swinging arm, but I realized that scheme wouldn't work.

The two sides of the differential need to be aligned, supported in two places, and also locked in place. The swing arm would not have held the differential still. I would've had to add more structure to properly immobilize the arm. More structure, more weight. So I abandoned the swing arm and reimagined the supports as a box that would be suspended under the chassis at a specific location. 

Instead of drilling more holes into the chassis, I reused the mounting holes of the already installed butterfly brackets to secure the new differential frame, replacing the short bolts with long threaded rods. The holes were well defined, making it easier to center the differential on the wheel axles.

After measuring the area created by the threaded rods, I designed aluminum I-beams to hold the differential's axles and attach to the threaded rods. Each axle had to be supported in two places to prevent the differential from twisting or pinching so I also designed standoffs that bolted onto the I-beams. To keep the I-beams lined up with each other, I added notched cross-beams that locked onto the front and back of the I-beams.

Making the pieces was another CNC fest, though I worked on simpler parts and features separately while the Tormach sculpted the harder ones. I drilled the bolt pattern on the I-beams using the manual mill and tapped the holes manually. I also made the cylindrical standoffs using the lathe.

With the parts fabricated, I was ready to assemble the differential's frame. After bolting the standoffs onto the I-beams, I seated the differential between them, then clamped the crossbars on to create a stiff box around the differential and slid the entire assembly onto the threaded rods. I adjusted the location of the nuts to level the differential front-to-back and left-to-right. I reconnected the front wheel axles. The length of all the axle connections pieces was longer the the space available, so I had to remove the tires to slide the parts together.

We are ever closer to riding the Falcon out of the garage. It's just a matter of reattaching the Hyperdrive's drive chains to the differential, pedals, and rear tires; finalizing the steering; and reattaching the brakes. For the glory!

Rudy August 08, 2025

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I Told You This Was Going To Work...No Problem

With an assist from Andee, we assembled the new suspension system for the Aluminum Falcon! 

Nice, right? I spent most of a week preparing for the effort by test fitting one side to determine the number of bolts, nuts, and bearings needed to complete the assembly. 

After I cut lengths of 1/2-inch and 3/4-in threaded rod for attaching parts together and drilled holes into the chassis to connect the fulcrum brackets, I discovered two design fails that needed to be corrected before I could assemble the suspension, both related to the hangers. 

Each hanger is made from a couple of tubes connected by two bars, forming an "H". The problem with the inside hanger was that a crossbar on the chassis prevented installation. The problem was there the whole time and I just didn't notice it.🤦🏽‍♂️ Or I noticed it and forgot. Whatever. Look out the window.

Luckily, it was easy enough to fix. I cut a slot out from the lower tubes that was both wide enough to get around the chassis crossbar and installed additional bearings into the newly revealed holes.

The outside hangers had a different interference issue. We needed the attachment plate on the lower leg of fulcrum bracket to fit through the hanger, but the attachment plate was too big.🤦🏽‍♂️ 

To fix this issue, I used a bandsaw to trim down the length and width of the attachment plates to fit within the "H" of the hangers. I then used an angle grinder to round the corners to clear the welds on the hangers.

Once the hangers and fulcrum brackets were modified, I also had to make slight modifications to some of the bronze bearings we use to support the joints. I could not find bearings in the length I needed. I needed 1-1/2 inch sleeve bearings, but I could only find 2 inch. I needed 7/8 inch long flanged bearings but I could only find 1 inch. I had to buy the longer bearings and adjust them in the machine shop. 

I turned the sleeve bearings down to size using the lathe. That was easy enough to do. The flanged bearings were not as easy. They were impossible to hold in the lathe because the flange stuck out like the rim of a top hat.  Instead, I had to use the mill, but holding the flange in the vice was still tricky to do.

Because bronze is soft, it deforms if you squeeze too hard but the vice needs to be tight enough to hold the part while it was machined. I turned two round bearings into eggs finding that out. To avoid ruining more bearings, I made soft jaws out of plastic. The plastic is softer than bronze, so it got squeezed instead of the bearings.

This allowed me to hold the bearings more tightly without damaging them.

Once the stop nuts, washers, custom bolts, and bearings were ready, I made assembly kits for each side. 

After days of preparation, Andee and I got to work assembling the new suspension.

The last piece of the suspension system--that holds the whole thing together and makes it all work--was a heavy-duty tension rod that connects the two lever arms. After a healthy dose of WD40 on the threads, I attached the rod. 

Spinning the turnbuckle in one direction pushes the levers out, lowering the chassis into race mode. Spinning in the other direction pulls the levers in, raising the chassis six inches to get us through the mud and water.😎

Next up: I have to install the differential to complete the assembly of the front axle. That requires rethinking the support brackets...again. But I have a plan for that. I also have to make and install all the steering components. The work continues. For the Glory!

Rudy July 31, 2025

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