We're firing on all cylinders now. I mean, I'm desperately trying to keep all the spinning plates in the air. Race day is one month away and there's still a lot to do. We've made more progress on the front wheels, seating, pedals, and we've started the "canopy."
Front Wheels
I finally finished the last two pieces that secure the front fat tires to the CV axles: the outside bolts that screw directly into the CV axle. It was my reacquaintance with the lathe. It was not rudimentary.
The first one took a while and had a lot of chatter. It's not supposed to chatter. After our machine shop captain pointed out all the dumb things I was doing (my words, not his), the second one took half the time and hardly made any noise. The highlight of the job was drilling and tapping an M16 hole in the stainless steel bar. I had to walk through 6 different progressively wider bits to get up to the 14.5mm diameter pilot hole. I also used the lathe to tap the hole.
The CV axle threads onto the bolt nice and easy, like I planned it. 😎
I then had to mill flats into the hub bolts so a wrench could be used to tighten them down. It took a couple of tries. During my first attempt, I did not set up the part very well and burned out my end mill before I realized. That's when the tool gets so hot that it melts the material instead of cutting it.
Turns out I was spinning the end mill too slowly, milling in the X direction instead of Y, and taking too shallow a cut per pass. Our machine shop captain informed me that a shallow depth-of-cut concentrates too much heat on the corner of the tool, quickly destroying its sharp edges. So that's how it happened. It makes sense when someone with a ton of experience says it. 😅
SO, spin twice as fast, use more of the side and less of the bottom of the tool, and work in the Y direction. I also centered the part in the vice and used the mister to spray coolant on the end mill while it cut. The new parameters did the trick!
The inside surface of the hubs I purchased had a small lip on the outside edge of the tubes. They need to be smooth all the way through so the hubs stay in full contact with the axle spacers and bolts. Otherwise, the wheels would probably wobble. I used a Dremel tool to grind the lips down flush. All the parts now slide snugly into the hubs.
The last manufacturing step is to assemble the hubs and axles then drill holes for clevis pins it's just the "simple" task of rebuilding the front wheels. I did this for the first time ever with the back wheel. Hopefully, that experience will make these next two wheels a little easier.
Seating
I worked on the structure that supports the seats. Two thick aluminum tubes are attached across the main truss. They are notched and bolted in place. Steel angles are bolted to these tubes to support the seats.
We are using the seats from last year's sculpture, Big Fish. Other than some bicycle hardware and loose PVC, these were the only things to survive deconstruction..
However, to use the seats they have to be modified. They need to be freestanding and slide on the steel angles so pilots can adjust their position relative to the pedals. The seats need to be on rails
I cut and shaped rails from the same electrical conduit that we originally used to make the seats (more deconstructed material from Big Fish) and notched them so they fit snugly up against the existing seat frame.
Once everything was notched and dry-fit, I then carefully welded the new tubes to the existing seat frames (without melting any of the seat material!).
Now the seats are freestanding and they're adjustable.
Pedals
The sculpture still needs pedals to make it kinetic. We were originally going to make custom frames, but time marches on. After a couple of visits to The Bike Connector's junk pile, we were able to find two aluminum bike frames that were destined for the scrap heap.
I did some work figuring out how the frames should be oriented and how they will attach to the Falcon.
The bike frames will tilt back like they are "popping wheelies." The pedals are placed so the pilots can use them recumbently. The freewheels will end up under the seats and roughly line up with the input shaft of the Hyperdrive. The seat post is a great spot to mount the steering wheel!
Canopy
We've been talking about the kinetic part for so long, you might think that we forgot about the sculpture part. The canopy will give the Falcon its look.
We started with the giant loop that makes up the Falcon's saucer. I turned to Jen, one of the members at Lowell Makes, who makes lyras out of steel tubing. She graciously spent the better part of a day teaching me how to bend tubes. I learned a lot from her, enough that I think maybe I could do it alone. Haha.
We used a tube bender with a motorized attachment to shape the large outer circle of the canopy from super-thin aluminum tubing.
It took three 8-foot tubes to make the 80" ring. 😎
I made custom collars to join all the seams. This should make it a little easier to weld.
Next, we will attach all the straight pieces: the mandible tubes and the support structure for when it's attached to the base.
To get the canopy to look like the Falcon, we plan to build a thin cage on the canopy frame and lay out "cosplay" foam sheets over it. We'll layer the foam to build out the surface features. The more accurate we are to the scaled up features, the better the canopy will look. But we don't have time for too much experimentation.
I came up with an idea to hopefully lay everything out to scale without too much work. I purchased a model for 3D printing the Falcon. It's actually a bunch of models that you can print out and assemble a 16-inch scale model in plastic. I imported all the pieces into Fusion360 and scaled everything up to the size that we will need for our sculpture.
Then I created full-scale drawings of each section and its features. Here's one for the half of the drive section in the rear (in purple)
We'll print them out on large sheets of paper and use them as patterns to trace onto the foam sheets. It's going to loook awesome!🤞
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