Hunter Park Kindergarten

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Thursday, March 26, 2009

Wheels

After building his fire engine Sam built a roller. He had detailed plans showing all the parts. I wrote the names on the plan for him as he showed them to me.
Roller finished now he's built a ute. Four exhausts and hand made wooden wheels on the back.

Henry got inspired and decided a motor bike with a real engine is the thing. After our email around for more wheels, from old and broken toys, Henry brought in the back end of his old trike and we started on the bike. Like Sam he drew up plans, in this case from a picture he found in a magazine. Henry tells me mum and dad are looking for a motor off their old barbeque. "It should be just right." Mum says though that they haven't found it yet. I told her we're hoping to get the son of one of the teachers, at the kindergarten the next town over, to pay us a visit. Last year he made a miniature motorbike at college and raced it.

video
After hitting the bump, Henry had to make some modifications, upgrading the suspension and changing the bamboo axles out for metal ones. Fortunatly the hack saw let us convert the axle off his old trike. Since then he's taken it home and added on a brace under the seat, making a strong triangle to hold him up.
Ollie meanwhile continues investigating the Strandbeast with Xander. We brought the motor but there was not enough grunt, it couldn't turn the legs. So I brought some gears, a little one on the motor turning a big one on the central axle to increase the torque (grunt). We got ten times more grunt. video
Better but it still needed work more torque. Notice how it catches.
A quick bit of lunch break research showed putting a little gear on the same axle as the big one, meant it could turn another bigger one, multiplying the effect of the two sets of gears. I stuck three extra gear sets on, we now had 250 times more grunt and 250 times less speed. But now it's legs kept collapsing and jamming when we tried to get it to walk on it's own. Ollie suggested wheels on the feet as he'd seen one on youtube that had wheeled feet. It was a great idea but it's still staggering not walking. Looks like we'll have to build version 3 in wood, or make the joints stronge and more rigid.
These three axles are turning at different speeds as we're gearing down the motor to decrease speed and increase torque.

The blue gear (hidden far left) is turned by the motor. It turns the yellow gear (left most). That yellow gear is on the same axle as the blue gear (1), which turns the yellow gear (1, 2). The yellow gear 1 is on the same axle (2) as the blue gear (2). The blue gear 2 turns another big gear and so on.


video

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