I've currently moved over to blogging at http://mathcraft.wonderhowto.com/

Here I will be posting about 4 times per week and will have a project every week with more in depth information and a how to component and templates. There will also be a user forum for people to submit pictures and ideas.

Thanks! I hope to see you there!

Copernican Planetary Orrery (Gears for Earth and Mars)

I spent a little bit of time on the wooden orrery today. Click here for the original post and description. Two more sets of Gears are done (Earth and Mars). Earth's gears are one to one. Each time the driving gear turns once, the planet will spin once. Also everything in this orrery is based on Earth so in some sense there is no error in this gearing. For Mars we have the first of the reduction gears. The gear driving Mars is smaller than the gear Mars is on so Mars spins around slower than the gear driving it. The driving gear has 25 teeth and the gear Mars is attached to has 47 teeth. This gives a year length of 47/25*365.2425 =686.66 days. Mars' orbital period is actually 686.98 days. So there is an error of about 1 part in 2200 (about the same as Mercury and about double that of Venus.) The gear stack is starting to look pretty impressive.

Earth's gears

Top view of gear stack (Mercury - Earth)

Side view of gear stack (Mercury - Earth)

Mars' gears

Top view of gear stack (Mercury - Mars)

Side view of gear stack (Mercury - Mars)

Close ups of gear stack (Mercury - Mars)


Post a Comment

Popular Posts