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In 2005-06 three students did work on the Kinetic Sculpture. One improvement was to re-build the braking system, it's nice to now be able to stop. Also, in coming off the trailer at 50mph two wheels were taco-ed. New rims were obtained and and all four wheels re-built.

In the 2006 Arcata race the new wheels did not hold up. Within 10 miles they were beyond repair. A buckling of the wheel rim in the picture above can be seem at about the one-o'clock position. Upon subsequent investigation it was found that the new rims were of a thinner gage than the old ones. So much for "new" equipment. That was the end of our Arcata race. An interesting note, the wheel seen above with "Not So Easy" on it was the wheel that failed first.

For the Klamath Race two old rims were re-laced for the front "pod". Also a strip of sheet metal was welded around the outside of the front wheels. This gave a closed cross section making these wheels much stronger. These modified wheels have held up well so far. The "Not" in "Not So Easy" was removed making the wayward wheel read "So Easy". The vehicle was able to "Ace" the Klamath race. There were some minor difficulties but these were easily overcome literally on the road (i.e. while moving).

At the Corvallis Race the Big Easy ran very well. It "Aced" the course and won the Wizard's Choice award.

One side note. In 2005 it never seemed the inner tubes in the wheels were of much use. In 2006 we did some water testing with one goal to show that the inner tubes were not needed. So, testing was done with those inner tubes deflated. The results are shown below:

Engineering

Several engineering refinements were made in 2005-06. Probably most important was an improvement in the brakes. A new set of motorcycle disk brakes replaces the original automobile disk brakes. The big improvement was in moving the brakes from the main axles back one chain drive. This final drive is a 4:1 #50 chain. This move, and brake improvements, gave an improvement in braking of over 4 times. We had excellent braking for 2006. We're in trouble if the #50 chain breaks though as our braking goes through this drive.

Two bicycle drives feed into a common shaft and then to the high/low gearing on the front and back. The original design was for three shafts here with soft couplers between. Thus there are six bearings. In 2005, a very busy year, we weren't able to find find soft couplers for this. Thus a single shaft went through these six bearings. It is nearly impossible to line up 6 bearings so this created quite a bit of drag. In 2006 these shafts were cut into three front and back with chain couplers. This decreased drag a noticeable amount.

The gearing in the steering differential rotates anytime the vehicle is moving. This wasn't considered in the original design. These differential shafts were supported in nylon bushings rather than roller bearings. Also, the steering yoke (holding the steering crank) was supported on the steering differential shafts with nylon bushings. This all created considerable friction. In fact these bearings became noticeably warm in 2005. In 2006 needle bearings were fitted to hold the steering differential shafts and the steering yoke support was moved from these axles. Together this reduced parasitic drag a noticeable amount.

A failure was in re-building the wheels. We obtained new rims as the old rims are somewhat bent and dinged. We were also breaking spokes though the 2005 season. After wheel failures in Arcata it was noticed that the sheet metal used on the new rims was considerably lighter than the old rims. The manufacture had changed between the original old used rims and the new shiny ones. This reduced rim strength by some 40%, enough to eat up the safety factor and then some. After the Arcata race the two failed wheels were replaced with old rims. The two intact wheels were reinforced with a band of sheet metal around the outside. This band was welded in place and formed a closed rim cross section. No analysis was done but this should increase the rim strength many fold. These wheels held up very well through the Klamath and Corvallis races. It has seemed to help with spoke failures also.

A two speed steering drive was attempted. Here an over-center mechanism was used to shift between a high and low steering crank gear. It turned out the chain length was enough different between the two gearings that the over center mechanism wouldn't function. Only one steering gear was used racing in 2006.

All in all the refinements done in 2006 greatly increased the speed of the Sculpture. Small refinements were well worth the effort. Having brakes that worked was also a nice feature obtained in 2006.

STUDENTS

Mark Fullenwider	Design/Fabrication
Chuck Burgess	Design/Fabrication
Zack Grant	Wheel Man
Evan Pickett	Bribe Molds