Unwheeldy Construction


May 24, 2005

Well, only a few days left until the race. We took the vehicle out for a test drive this last Sunday, and it worked pretty well. It definitely demonstrated that pneumatic tires would be nice. After 30 minutes or so of driving it, my chest felt all funny from laying on my back and being vibrated.

Tim took some photos of Elena and I riding it in our neighborhood. Here's a front view:

Here's a side view in front of someone's van:

And here's the rear of that van... I think this is either Richard Feynman's old van, or one inspired by him. Check out the Feynman diagrams in the paint job, and the "Tuva or bust!" bumper sticker. Makes some sense, we were right near Cal Tech at the time.


May 14, 2005

Holy cow, and it floats too! We did the first water test today at the Santa Fe dam near here, and it actually worked. The paddles are plenty big and once we have them all on I think it will really cruise. These photos are courtesy of Tim Crowder, thanks Tim! My camera is fritzing again.

So here's us out on the water, practicing our coordination (result: not too bad when Matt is in charge, he has actual boating experience).

And here's us climbing the boat ramp out of the water... which was just great until we got all the way out and realized that in our hurry we'd neglected to reconnect the brakes. Tim and Elena were able to catch us in time, thankfully!

So there it is! It didn't capsize even once. Now I feel like all the remaining work is just to make it more comfortable and convenient. Like making a better way to carry it in the trailer so the wind doesn't catch it and lift it at freeway speeds. Details details.

Many thanks to Matt and Ana and Elena and Tim for making the test possible.


May 4, 2005

I can't believe it actually works! Elena and I drove it for the first time tonight. We pedalled the big awkward thing around the cramped space of our back yard. (It seems like a big yard until you try and drive around in it. :) It felt so cool. It will definitely take some practice to drive it smoothly, but it also feels like that will be possible. Mainly though, it feels fun! Both the diff-drive coordination between the drivers and the swinging you get from hanging below the axle are hilarious to feel.

Here's the vehicle with no riders:

Here's me posing for a photo in the driver's seat. Notice the comfortable "dying bug" posture required to drive it.

Elena did some nice photography of it, so here's a separate page with full-size photos of the vehicle and myself.

Also, thanks to Elliot Naess for suggestions about making the brakes not give out in the middle of the race. He brought up the good point that the calipers are higher than the reservoirs in the current design. If any bits of air get in the system they'll accumulate in the calipers (dangerous) instead of in the reservoir (safe). I'm not totally sure how we'll handle it, but regardless it's good to be aware of the issues. I'm thinking either new brake levers with separate reservoirs OR mount the existing levers up high and connect them with linkages to home-made levers on the handlebars. Hmm.


May 3, 2005

Today I finished adjusting the mounting of the first brake. It feels good to know that we can at least stop the motion of the left side of the vehicle now. After a trip to The Hoseman today we now also have an 80 inch long brake line and enough brass washers to do the right brake as well. Surprisingly, out of the 1800 types of fittings they have in stock, they didn't have the specific kind of banjo bolts we needed. Tip: when buying brakes from the motorcycle junkyard for your vehicle, don't just take whatever they bring you. Find out FIRST what types of hose couplings and connectors are common and cheap, and then buy brakes with THAT kind of coupling. I'm learning so much from this project. :)

So here's a pic of the left brake. Clearly the handle is not installed yet, but there's some more bleeding and fussing to do anyway, so I didn't bother putting it on the handlebar yet.

You can also see that the big gear has been mounted to the wheel and the chain tensioner has been fabricated and installed. Not bad, though I do say so myself. (It's not fully tense in this pic.)

Also, check out Tom Jones' pics of the 2005 KSR in Baltimore! With blazing speed he has a ton of pictures and nice writeups already posted, a mere 2 days after their race. They've really got some great sculptures this year. I was sad to miss it, but somehow it seemed like I had enough work here to keep me busy.

In other news that stresses me out, I've learned this weekend that our landlord is selling our house out from under us. Potentially we've got as little as 30 days to clear out, though it depends on how fast the house sells. Anyone know a place to live in or near Pasadena with a big garage?


April 27, 2005

Hooray! The big gears have finally arrived. McMaster-Carr couldn't deliver, but I found ABL Products in Cleveland that had 112-tooth #40 sprockets in stock, and they shipped them right out. They're wonderfully enormous. I think we'll want to cut some big holes in them to save weight... their shipping weight (for 2) was 39 pounds. I'll post a picture when I get home.

OK, here I am at home. Somehow when placed on a wheel the gear doesn't look so large. Here's one of them:


April 24, 2005

Camera is working again! Here's me celebrating by holding a wheel over my head:

And here are both wheels leaning against the patio roof. In case that's not enough for scale, you may be able to make out the regular mountain bike just behind them.

And finally here's one showing the new seat position, very low and forward:

With the new seat position the carriage hangs almost level, so I figure we can trim it the rest of the way with luggage or counterweights reasonably.

We have also now bought the plastic for the hull material. I was amazed that we found a place that could sell us 5 feet by 11 feet of 1/8 inch thick clear polycarbonate (like Lexan). They just have a giant roll of the stuff and they cut it to length. This was Gavrielli Plastics in Hollywood. Nice people, but watching them work in the stock yard was scary. I thought we were going to witness an industrial accident, but somehow no one was hurt.

Just as importantly, finally FINALLY the main drive gears have shipped. They should arrive Tuesday or Wednesday. McMaster-Carr couldn't get them to us until July, though for some reason their web site kept saying they were going to ship in two weeks. Two weeks from whatever day it happened to be, of course. Feh. I found the July date by calling them and asking what was up. After cancelling that, I found a sprocket company (ABL Products) in Cleveland that had them in stock. 112-tooth #40 sprockets, how many do you need? Awesome. So now I'm just waiting for them to arrive. Once the drive gears are on we can finally for the first time only 1 month before the race pedal the darn thing and see what happens. I'm excited and scared to try it out. (What if we've missed something serious?)


April 11, 2005

Camera still broken, but today the Vehicle rolled on its own 2 wheels for the first time! It was so fun to climb on and roll down gentle slopes in our yard and driveway. It's like a porch swing on wheels, it feels so weird.

To go along with the big happiness of the 2nd wheel being done and the thing rolling, we found a big frustration. When Matt and I sit in our seats, the center of gravity is too far back, and the carriage leans back maybe 20 degrees. It would just be humorous if not for the water issue. If it sits back 20 degrees it means the edges of the boat will be much closer to the surface of the water and could sink too easily.

We thought of 3 solutions: 1) put a giant counterweight on the front, 2) move the seats forward until our CG is in the center, or 3) turn one person around and have him face backwards. I realized 1 doesn't work because it means we can't get out of the Vehicle when it's on the water (like if it needed to be towed, heaven forbid) because the counterweight would tip the front end clear down into the water. 3 doesn't work because none of us wants to go through the race looking backwards and having pedalling commands shouted at us. So we're left with 2, which means a bunch more sketching and then a lot of cutting and re-welding. Oh well, a lot of the tubing and drive system are still just tack-welded, so that's not too bad.


April 6, 2005

It's a shame my digital camera is not working right now because the FIRST WHEEL is DONE! Woo-HOO! It's not perfectly true yet, but I spent about an hour tonight getting it within about an inch of true both radially and axially. It's so pretty... I think I spent a fair amount of time just staring at it.


April 3, 2005

Less than 2 months to go, but we're finally putting the wheels together! I hope to get at least one of them laced up today. Chris came over yesterday and helped out a lot, and today both Tim and Claudine plan to come help. Thanks guys!

So here's our wire order when it arrived:

I love that they didn't put it in a box, they just stuck a shipping label on the wire and gave it to UPS.

Also I've made a lot of progress on getting the bicycle drive trains installed. Here's the latest of that:

I made another trip to the bicycle kitchen and came back with a big bag of parts for cheap. Such a great place. I haven't installed all that I got yet because I'm still waiting for a couple more parts in the mail that I didn't realize I needed at first.

I don't know how other people do it, but I needed to attach a bicycle freewheel (the rear set of gears with the ratchet built in, pictured at left) to a secondary shaft. My approach was to cut up an old steel rear wheel hub (pictured on the right), bore the center out to 5/8inch (on the metal lathe at work, thanks!), and then weld on 2 shaft collars with set screws (finished version in center). Then finally it can thread onto the gears on one side and set-screw onto the keyed shaft (not shown). Seems like there's got to be an easier way, but I really didn't want to be welding the delicate bicycle gears right onto the shaft.

Oh, and my spoke design has changed a little bit. I tried threading the ends of the wire with a 2-56 die, and I did get it to work a few times, but I went through a total of 3 dies and many wire ends in the process. Here's one installed on the wheel that worked (on the left) alongside the new way on the right:

I gave up on threading the wire as too difficult and error-prone and instead am welding little chunks of stainless threaded rod onto the ends. Then I use narrow little nuts (meant for circuit board standoffs) that I thread on from the back. Here's what those look like:
The result is not as elegant as I hoped for, but it is SO much faster. I don't think I would have been able to finish in time with the threading approach.


March 15, 2005

Today the spoke wire samples arrived! Yay! Now I just need to head back to the hardware store to replace the die I broke on the wire that was too hard.

Also today I learned of the lovely web page of Bob Durst's KSR Vehicles. It looks like he did essentially a one-person version of what we're doing, only he used a couple of differentials so he can steer some way other than just differential braking. Very clever indeed.


March 13, 2005

Here's the latest:

This week both Tim and Elena helped out. Thanks! We got the axle welded onto the rest of the frame and the bottom brackets (where the pedals attach) are both on now. Also the hard (rigid) parts of the seats are done, that's a good accomplishment. They'll need a bit of upholstery of course. :)

Still waiting to hear from the spoke wire company. Yikes.

Oh, plus I ordered a bunch of parts from McMaster-Carr and some go-kart parts supply place, so when that arrives we can really make some progress on the drives. That should be fun.

That's Shadow to the right of the frame. He helps out a lot too.


March 7, 2005

I decided to switch to a most-recent-first web page format. Am I a blogger yet?

Philip took this photo of me yesterday trying to hold the axle in the correct place in space relative to the frame. As you can see, the wheel hubs and axles have finally been machined so they fit together. Cool.

Though I don't have a photo of it, today I finished the bulk of the first seat and its attachment to the main frame. Looks fine actually, I had my doubts. Next I need a helper to pose for me while I figure out where the bottom bracket and thus the pedals will go, and if I can put the secondary axle where I imagine it should go, or if we'll need different-shaped shins to make that work.


February 27, 2005

Today I finally finished the wheel hubs! I went to work this morning where Steve showed me how to work the metal lathe and we figured out how to use the "steady-rest" and cut bearing seats in the ends of the big aluminum tubes that form the core of the hubs. Then I came home and welded on the lovely CNC-machined flanges as well. Here are the results:

The ruler on the table is 12 inches long, to give you some scale. The hubs are each about 18 inches long, with 8 inch diameter flanges. Luckily welding the flanges on did not deform the bearing seats enough to be a problem, the bearings still fit nicely. It did change most of them from slip-fit nearly to press-fit though, but then that's what I wanted to begin with.

So now the wheels are only waiting on the spoke wire. Once that arrives I want to have a wheel-building party. 120 spokes per wheel would take an awful long time all by myself.

I finally got all the seat-adjustment holes drilled and reinforcements welded on the frame pieces, so hopefully the next thing to do will be welding the frame together. Then I can start on the seats and the bicycle gearing and the hull and yes this is a big project. Only 3 months left.


Tonight I finished the initial welds on the two side frames for the carriage which will be suspended from the main axle. Here's what one looks like:

The welds don't go all the way around each joint yet, but enough is there to keep it together well.

The .059 inch wall-thickness steel tubing sure is easy to burn through. I'll have a few little areas to patch when I finish up those welds. Oh well - it's still way easier than those aluminum wheels.

Yesterday I got a sample of "full hard" stainless steel wire in the mail. We were thinking of using it for spokes, but after breaking a die on it while trying to thread it for a nipple I decided we need a bit softer metal. Helen is the nice woman at GDC/Sunset Wire who's been helping me, and today she said she'd send out two softer samples.


For the record, I'm keeping a pile of related photos on a separate page.


So Matt and I are putting together a Kinetic Sculpture Race entry this year. We hope to race in the Arcata to Ferndale race this Memorial Day weekend. If it works I think it will be hilarious.

There's only a few, but here's some photos of the rim being built.

Here's one of the 2 wheel rims for our KSR entry. That's Matt holding Holden on the left and Paul on the right.


Last modified: Mon Jan 30 02:52:40 MST 2006