kiddo projects

koyote

koyote

Joined
Mar 29, 2007
Messages
5,846
since I spend a certian amount of my time as the schoomaster over here in homeschool land, I need to start sharing a bit.

Today, as part of our middle ages work, Leif and I (mostly Leif) built an onager.

I did break out the books to explain the stretching forces of nylon.....

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Very cool!

What did you use for the nylon spring? Also, could you take a closer pic of how it attached to the launching arm?
 
I'll get close up shots. But basically, it's mason twine (any twisted nylon rope will work, from mason twine up to half inch, but this is a baby catapult)

you make a hank, like coiling rope around your arm, and the throwing arm goes right in the middle. once you twist the ends (with the bolts) to a tension point, it goes!

I will get better photos, especially as I'm making minor improvements
 
I need to build one of these that will launch oranges, since I have plenty growing in the back yard!
 
great stuff Christof... our older son and I recently built a small battering ram, as part of a school project... it was a lot of fun..

Leif is getting big...:D
 
Parents are getting way too competitive with these school projects, maybe they should split the grade in half.
 
I need to send the updated photos, too! haven't gotten them yet, we're having the christmas brain melts going on.

It's worse than regular school, we homeschoo,, so it's far more competitive. Homeschooled kids are limited as much, so some realyl crazy things get made :D
 
It's pinewood derby time again.

Leif has a lot more involvement this year:

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more machining!

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hand sanding before we get to the weight addition issues:

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And we have a weight of about .... 2.25 ounces, less paint. Last year, we were at 3.5 ounces, and I used 1/4 inch brass pin stock inserted into drilled holles to make up the weight. But we calculated it out, with the showlower holes because of his Stingray style car, and it would be approximately 22 holes to get it up.

Well, we need something beefier than 1/4 inch brass. And not going to town today...

Well, it's always possible to use lead, right? As long as it's coated it's safe.

hrm. coated lead.... hrm.

Okay, so we're going to go with 5 (I wanted 6, but that would have been 4.8 ounces without paint!) exposed copper colored "cylinder heads" along the top of the hood. It's a straight 5! Copper coated lead cylinder heads of exactly .358 diameter.... :D

Here's the dude drilling holes:

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We'll see what it looks like once it's painted and the semi-wadcutters- I mean "cylinder heads" are in place.

In the meantime, the nails you are required to use for these things have flashing on the heads and ridges all over.

So, what to do???

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Yes, my 7 year old is (with a lot of help) turning 1.25 inch long nails.....
 
Holy Crow that's some great work! What confidence and real-world skills you're providing him. Bravo!
 
and here's my Wolf with the .38 special stingray. (he wanted the cylinder head look. I should have checked his depth, we coulda got another 1/16 to 3/32 of depth on them. But he's 7, and he did the car about 85% on his own. Mostly I helped set up some jigs and evened out his sanding a bit on a slack belt after he shaped his curves.

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good job - on both parts, you for teaching & letting him do the work, Leif for listening and doing!
you going to let him make a knife & sheath for his craftsmanship badge?
 
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