pic: VEX High Reduction Gearbox

[dlavery]

Heh - very cool. If you could "drive" the big wheel from the Earth to the Moon (at apogee, the approximate distance is 251,968 miles), the little wheel would turn only 4.1629 times.

-dave



.

[Rich Kressly]

Originally Posted by dlavery

Heh - very cool. If you could "drive" the big wheel from the Earth to the Moon (at apogee, the approximate distance is 251,968 miles), the little wheel would turn only 4.1629 times.
-dave

Say we're driving on the big wheel to Mars ... how many little wheel turns?

[dlavery]

Originally Posted by Rich Kressly

Say we're driving on the big wheel to Mars ... how many little wheel turns?

At closest approach (such as during the perihelic opposition in August 2003) the Earth-Mars distance can be as small at 34,646,418 miles. In that case, the little wheel turns 572.418 times. During conjunction, such as the one just ending this week, the distance can be approximately 247,821,000 miles. In that case, the little wheel turns 4094.437 times. I would find that number to be excessive, so for a Mars transportation application I would want to add on at least one more 12:60 reduction stage.


-dave



.

[AdamHeard]

Originally Posted by dlavery

At closest approach (such as during the perihelic opposition in August 2003) the Earth-Mars distance can be as small at 34,646,418 miles. In that case, the little wheel turns 572.418 times. During conjunction, such as the one just ending this week, the distance can be approximately 247,821,000 miles. In that case, the little wheel turns 4094.437 times. I would find that number to be excessive, so for a Mars transportation application I would want to add on at least one more 12:60 reduction stage.


-dave



.

I would like to thank both John and Dave for finally making me understand how far away mars is

[Raul]

All I can say is - we are such geeks!

[JVN]

Originally Posted by Raul

All I can say is - we are such geeks!

Totally... and proud of it.

Are there people out there who don't geek out over stuff like this? Weirdos...

[Abrakadabra]

Arthur Ganson has a sculpture at the MIT museum called "Machine In Concrete" that consists of a 12-stage geartrain, where each stage reduces the speed of rotation by a factor of 50. The left end is spinning furiously at around 200 rpm; the right end is embedded in a concrete block. The end in the concrete makes one revolution every 2 trillion years or so.

Here is a partial picture of the machine from Ganson's own website:
http://www.arthurganson.com/pages/sc...te%20page.html

But to really appreciate it, you can see a video of the sculpture (and Ganson's comments about it) at the 8:30 mark in this video from the 2004 TED conference:
http://www.ted.com/index.php/talks/a...sculpture.html

[T3_1565]

I have always wondered how fast you would need to spin something for it to spontaniously combust.... care to give it a try??

[Greg Needel]

Along these same lines anyone care to predict what the lifespan of a vex motor constantly running would be?

[Rich Kressly]

Originally Posted by Greg Needel

Along these same lines anyone care to predict what the lifespan of a vex motor constantly running would be?

I don't know the answer, but we're certainly thinking about doing the same thing

[Rich Kressly]

Thanks to senior Petra Hartman LMHS now has its own version of the JVN High Reduction Gearbox to teach gear theory to 1712 members and students in the Engineering Design classes. Woot!

http://www.chiefdelphi.com/media/photos/33863?
http://www.chiefdelphi.com/media/photos/33864?

[IKE]

Originally Posted by JVN

Totally... and proud of it.

Are there people out there who don't geek out over stuff like this? Weirdos...

Apparently there are others outside the realm of FIRST that geek out about this too.


http://jalopnik.com/5302043/on-the-p...-transmissions

"Artist Arthur Ganson's creation called "Machine with Concrete" provides a beautiful illustration of the power of a transmission. Should you input only 1 lb-ft of torque, the other end could deliver 244 quintillion lb-ft.

Ganson's piece demonstrates the unbelievable power which can be generated through simple gear reduction. It uses an electric motor turning at a modest 200 RPM and mates it to 12 identical sets of 1/50th gear reducers for a total reduction of 1/244,140,625,000,000,000,000. Of course no material in the universe could actually deliver that kind of power without shattering into pieces and even if such materials existed, turning only one rotation at that speed would take over two trillion years. It turns so slowly that embedding the final drive in concrete will have no appreciable effect — ever. The universe itself is only about 10 billion years old, and in another 10 billion years the sun will expand into a red giant and consume the Earth anyway, the final drive having complete only 0.5% of one rotation."


My emphasis added to my favorite part.