Leave Them To Me. I Will Deal With Them Myself.

Fabrication of the new suspension continues. I made the last of the hanger brackets, so we can now officially attach the new suspension to the Falcon!

I also made the next four parts in the build: the alignment bracket that keep the hangers and the suspension arms in the same position, relative to each other.

These were deceptively difficult to make. First, because of their size, I had to hold them in the machine differently than usual. That wasn't too bad. I just moved the jaw bolted to the front of the movable block on the vice, onto the rear position.

Carving out the first side of the part went well. I like to call this the "Han in carbonite" phase.   

I was able to remove all of the interior material without cutting through the bottom of the stock plate. The stock I used is 3/4 inches thick and the bracket is .7 inches thick. That 0.050 difference made sure I didn't accidentally cut into the vice. Because the vice jaws were in the way, I couldn't cut along the outside of the part. That left the bottom .25 inch thickness of material to avoid that.

I usually just flip the part over and remove the "carbonite" layer to finish the part, but since I need to maintain bracket thickness I also had to precisely trace the outline of the part from the other side. That's why there was one hole cut all the way through the first side. That hole became the origin for all the flip side operations.  

I began finishing the second side by manually cutting away most of the extra material using a bandsaw. It didn't take very long and helped reduce CNC machining time.

Because the part is triangular, I had originally planned to hold it along the hypotenuse but that wasn't possible. In that orientation, the part is not wide enough for the vice to hold it. And, yes, it was also too wide to move the vice jaws back. smh

I was stuck. To finish the part, I needed to make a custom jig–a part to finish the parts. If I could clamp the jig in the vice I could then secure the triangular brackets to the jig. I began with a 6 inch by 6 inch stock plate and designed the jig to use the central trapezoidal shape of the part to keep each bracket from shifting or rotating. I added 1/2" threads so I could lock each part down onto the jig with bolts.

Using bolts on the inside of the part meant that I couldn't use the Tormach to finish the back face of the bracket, so I did it manually. I had to keep the face mill moving to avoid tool marks. It reminded me a bit of playing the drums.

Once the jig was complete, I slipped each faced bracket on, bolted it down, and cleaned up the outlines.

The jig made easy work of finishing the alignment brackets.

With these parts, we are 50% through the build!

Next up, the parts that attach the wheel to the suspension and all the remaining steel structural pieces. For the glory! 

Rudy June 03, 2025

Read more

It's Your Imagination, Kid

Over the last two weeks, I've made progress fabricating parts for the new front end suspension. Most of the thickest parts are done. Those take the longest to make on the Tormach. For example, each front bracket took 7 hours to machine from a solid block. 

After making the second front bracket, I checked its fit and discovered that the far side of the large hole was milled slightly smaller than the near side. This happened because I had to use an extra long end mill to reach everything. 

The free end of the tool flexes from the cutting force created. The longer the end mill, the more the end deflects. I had to slow down the travel speed considerably to minimize the forces acting on the end mill, but that did not remove the flex entirely. To fix it, I flipped the part over and widened the hole from the other side using a shorter end mill.

After the second front bracket was finished, I made one of two rear hanger brackets. It's shaped like a saddle instead of a circle so we can mount it further in on the truss.

The final test fit for the brackets was great. I haven't drilled mounting holes into the brackets yet. That will happen when we're ready to install the new front suspension.

We've Got Arms

While the Tormach sculpted away, I continued welding together the suspension arms that attach the wheels to the central truss. I used steel instead of aluminum for increased strength, but mostly because I had access to free steel and virgin aluminum is expensive. My welds are still ugly, but I think I've gotten 5% better. 😎 Out of 8 arms, I only destroyed, and had to remake, one arm. 

After welding the arms together, I re-machined the inside diameter of each tube to remove deformations caused during welding. This will make sure that bearings will fit into the legs.

With the two front brackets, one rear bracket, eight arms, and the two bearing plates fabricated, the front suspension build is over 33% complete. For the Glory!

 

Rudy May 21, 2025

Read more

Concentrate...Feel the Force Flow.

The rear cassettes on a bike traditionally spin a tire around a stationary axle. The wheel spins, but the bolt doesn't. To drive the Falcon, the cassette and axle must spin together. We needed a new way to secure the cassette/axle to the bike frame.

My last attempt did not shift very well, was very difficult to align and ugly, so so ugly. Because I used u-bolts to secure it, that required the plate to be very large. 

This time, my idea is to use the outline of the bike frame's rear fork to keep the bracket oriented correctly and locked it into place with a single bolt through the fork's mounting slot. I traced the outline of the rear forks onto graph paper and scanned the traces.

I pulled the scan into Fusion 360, scaled it up to match the size of the graph paper grid, and used that to model the basic bracket in 3D. 

I decided I should test the fit of the bracket before making it in metal. Printing the model in plastic first saves me some money and a lot of time, especially if it takes multiple iterations to finalize the part.

After I finalized the fit of the bracket on the rear fork, I had to figure out where to hang the rear derailleur. It took a few tries to get it in the correct spot. For the first try (blue in the image below), I put the mounting hole where it would go if I wasn't using a giant low gear (52T). I am, so it had to be lower than that.

The second try (black in the image below) was technically correct, but the derailleur was lower than I wanted, especially for the mud. I had also added the profile of a derailleur hanger but I placed it on the bracket backwards. 

For the third iteration (white in the image below), I swung the mounting tab forward 90 degrees and flipped the tab stop to point counter-clockwise. I also flipped the bracket front-to-back to get  the derailleur a little closer to the sprockets.

Everything went together surprisingly easy.

Though the test assembly is working nicely, the bracket still needs one more modification. The derailleur rotates forward too much when shifting, so I need to rotate the stop on the bracket 60 degrees counter-clockwise.

The co-pilot's bike frame is different than the pilot's, so I need to modify the bracket to fit the outline of those forks. After that, the brackets can be made in aluminum. However, if they hold up during tests, I may just leave them in plastic.

Rudy May 12, 2025

Read more

I Will Not Give Up My Favorite Decoration

Jabba's line demonstrates his stubbornness of vision. I get that. I have yet to create the picture of the Aluminum Falcon that's in my head. And I don't want to let it go.

The 26" front wheels made the v2 Falcon felt more like a wagon than a dragster. We had to use them to make room for the flotation and to stay above the mud at LKSR, but I didn't like it. To go back to 20" wheels for Falcon v3, we have to be able to raise the front end when we are off-road. This is how we'll do that. 😈

Since the front wheels are connected to each other, the distance between them needs to remain constant. This geometry allows us to lift the front 6 inches and still keep the wheels aligned correctly.

I previously made the wheel bearing plates, but there are MANY more parts to make before I can assemble the new  suspension. And I have to make two of everything. Last week, I used the Tormach CNC mill to make one of the four hanger brackets we need.

It took 10 hours to carve that part out of a large block of aluminum! I also fabricated the long tubes and end caps needed to make the 8 steel legs that connect the wheels to the chassis.

While the Tormach was working, I began assembling and welding the legs together. 

I was able to finish 3 out of the 8 legs. In total, I made 6 parts. Just another 30 parts to go! 

For the glory. 

Rudy April 30, 2025

Read more

Do Or Do Not. There Is No Try.

We DID NOT! And incidentally, there was a lot of trying. Our sequel had a lot of the same themes from the year before, but it wasn't quite the same "movie." 

There was no eleventh hour catastrophic breakdown the night before the race, but we did have to redesign the front and rear ends three weeks before the race. Last year was cold and windy. This year was wet, and still a little cold. 

Photo by Dave Hausler

We began the race very slowly. And at the back of the pack, but at least we were moving. We followed everyone onto the first obstacle, a cobblestone street called Bone Crusher Alley. We knew the cobblestones were going to be rough, but we only had to make it one long block. At least, that's what we told ourselves going in. 

Two-thirds of the way down the Alley, we were stopped by the race stewards. The leader of the race had apparently made a wrong turn, and the rest of us had followed. The traffic jam of slow-moving sculptures brought the whole race to a screech-less halt. We had to turn the Falcon around, but it was designed to move forward. 

We executed an awkward k-turn that involved dragging the tires sideways. All the jostling knocked something loose. The front tires cambered out unnaturally. Spokes began to grind against the frame. Then we stopped moving altogether. 

I jumped off the Falcon, grabbed a tire and yanked it back into place. I should not have been able to do that. After a few minutes, we realized that the bearings supporting the front wheels had squeezed out of holes like toothpaste. Once the bearings detached, it was all over. Again.

I kept a veneer of a smile on my face. My disappointment was deep. Our race was brief once more. Some have asked me if I'm going to give up on this racer after two poor showings, but, I am not deterred. The Falcon will Return. There is no try. 

Photo by Dave Hausler

Rudy April 15, 2025

Read more

I'm Standing Here in Pieces and You're Having Delusions of Grandeur!

With the front end rebuilt, we turned to the rear of the sculpture. We had to use the rear wheel at the front, so the back was now wheeless!

That was actually according to plan, but it was late in the game. Our hill test had revealed that the single rear wheel of the Falcon could experience large lateral forces if the sculpture titled sideways. This was a sure way to "taco" the rear wheel. 

We determined that using two wheels at the back would significantly reduce that possibility. Although that would technically make the Falcon a four wheeled vehicle, we would keep the wheels close to the frame so that it would still look like a reverse tricycle.

Rebuilding the rear end was easier than the front-end reconstruction, but the wheel hubs we used to build the new rear wheels were different than the front wheel hubs from last year. We originally thought we could use a single bar that supported both ends of each hub. However, the interior of the hubs are tapered. Hollowing them out would've severely weakened them. Instead of using one solid tube across the hub, we created steel inserts that slipped on from either end of the hub. 

The inserts were designed to be held in place by the same pins that secure the hubs to the shaft. Since the the hubs tapered before the inserts reached the pin holes, I added that same ~5 degree taper to the inserts 😎.

Water propulsion

Doubling the rear wheels and moving them to the outside of the frame opened up a spot in the back to mount a paddle wheel. We talked through several ideas. We could mount two thin 26 inch bike frames and attach paddles between them. We could also rig up a kind of snow/mud chain to an inflated wheel and attach fins to that. But both those options seemed like they would take too much time to implement—time we didn't have.

Then, Andee came up with a great idea that reused stuff we already had. We would take the now available 20 inch rim and bolt last year's fins onto the end. Adding the fins made the overall diameter 24 inches--well within the 26 diameter of the road wheels.

While I made the inserts, Kreg and Andee assembled the paddle wheel.

Putting it all (back) together

We dry-fit the road wheels and inserts on the shaft, then marked and drilled holes for clevis pins. We also marked and drilled the pin holes for the paddle wheel in the center. Then, we located the drive sprocket on the shaft and cut a keyway there to lock the shaft to the sprocket. 

All the pieces of this puzzle were finally ready. With one day until race day, I assembled the new rear end.

Once the base was rolling again, it was a mad dash to complete the rest of the punch list. We had to reconnect the wheels to the Hyperdrive (the sculpture's main drivetrain), rebuild the steering mechanism, rerun the brake lines, make the flotation support mounts, add lights and sound, and, of course pack up the Falcon and load out for the race. There was a lot of smaller things to do, but we still had most of the day left and we had help.

Kevin created a bluetooth sound box! 

The combination of 4 switches allowed us to select 16 different tracks from an SD card and played it over a Bluetooth speaker. Kevin, Greg and Andee also added lights to engine area of the Falcon.

Steve worked on the brakes, pedals, and derailleurs.

Andee added skid pads to the raft to protect it from scraping along the pavement.

Andee also attached the rear wheel chain.

We had already reconnected the differential at the front, but because of the new, wider wheelbase, we had to create and install extension bars to bridge the gaps. 

I managed to find weld-on adapters online and welded them to custom-length shafts to make the extenders.

The original front drive sprocket on the Hyperdrive was smaller than the rear sprocket. The ratio of the sprockets was the same as the ratio of the wheels. That way, when the sprockets turn, the different-sized wheels would roll the same distance over the same amount of time. This meant that the front wheels needed to spin faster because they were smaller than the larger rear wheel. 

With the wheels now all the same diameter, we swapped out the front drive sprocket to be the same size as the rear. Of course, this changed the length of chain needed to complete that loop. We ultimately had to insert another sprocket into the rerouted loop to keep the chain tight.

The last thing we needed to do was drill attachment holes in the poles that connected the main truss to the side pontoons of the raft. This was key to us not sliding off of the raft when we hit the water obstacle.

The sun was already up. It took ALL night, but we actually completed everything we needed to get to the race! We really tried to avoid staying up all night. We're too old to run races on zero sleep. But it was what it was.

We loaded the Falcon onto a rental truck and drove to the start line. It was time to see the Falcon in action.

Rudy October 09, 2024

Read more