Clockwork Solar System

[Orcman]

I'd like to share our MOC and my experience building it, that I (Chris Orchard) and Brent Waller (yes, that Brent of Lego Ideas sets 21108 Ghostbusters and 21328 Seinfeld fame) have been collaborating on.

Background
During one of our Covid lock-down skype Brisbricks (our LUG) social nights. Brent was talking about something he would have liked to have made, but found he just couldn't get it to work.  
He elaborated that it was an geared model of the solar system or orrery (which I had always wanted to try, but never had), and he lacked the Technic know-how to complete, so I offered my help.

We decided on dividing the work between the aesthetics and the technical, which worked well.  Brent was responsible for the overall idea and look, as well as the base and planets, and I was responsible for the gearing and arms.
We each gave feedback on the others work and I found that really helpful

I had written a number of Technic articles for BrisBricks to help members get a grip on how to integrate and use Technic in their builds.  
So I was sure I could make it work, especially as I just had that "A-Ha moment" of using the big ring gear driven internally by smaller gears (that would also keep the ring centered).

At first I thought it would be easy as the ring gear is a nice quarter circle, right?
That piece turns out to have a little quirk - it is pinched in at the end cross-holes (or bowed out in the middle depending on how you look at it)!
Check this video out to see what I mean.

This meant that the standard Lego spacing would create far too much friction - it would slow down as the ring "tightened up", then it would speed up as it became looser.  This wasn't what I wanted - I needed steady, constant speed.
It took me around 90 hours of constant fiddling with various techniques to get a geometry that was slightly under a standard spacing.
I found that a distance of less than 0.5mm would be the difference between it reliably turning, and gear slippage.

Gearing
Getting the gear ratios (planet orbit times) accurate was a key goal of ours.   This is a small snippet of the design spreadsheet that I used.

The original data is from https://space-facts.com/orbital-periods-planets/ and double checked with various NASA pages.
Most solar system transit times are based on earth.  Which would mean "gearing up" to make Venus and Mercury turn faster than Earth.  
I decided to turn that on its head, and base all the transit times on Mercury.  So every planet would be "geared down" from Mercury, the idea was to make the movement as smooth as possible.
In the spreadsheet this is represented by line 2.  In the end every planet was less than 0.15% out, most being less than 0.09%

It's really the introduction of the new 28 tooth gear that really enabled me to get the desired accuracy.
Having a 7 in the ratios really helped.  In the end I wrote a quick Perl program to help sift through the gear combinations.  That program could handle up searches to 5 gears deep

Early proof of concept video

The physical model was created first, to ensure that it all fit correctly.  The digital model was then created from that physical Moc.
The planets are driven by a single M motor and turns Mercury at about 2s an orbit. We should have a video of that soon.
Unfortunately for the physical model, I lacked the exact parts to make the planets just like the digital design, so an approximation of size and weight was used.

Compromises
Our goal was to create as accurate version of the planet's timings as possible, while still looking like attractive, but certain things had to be dropped.
By introducing another ring, I did get a Moon to orbit Earth too as a prototype, but it was unwieldy and really threw the aesthetics out, so it was dropped.
Pluto didn't make it, sorry.  Although adding a ninth face in the base would be easy (as would adding another ring), constructing a nice looking, strong nonagon(?) on the base top just wasn't possible.

MOC Stats:
2996 pieces
153 gears
15 months of collaboration
8 major revisions
2 completely different designs
3 gearing spreadsheets
1 custom written program to help work out the closest gear ratios

Overall I am proud of what Brent and I have created, and we hope you like it too.

More details, videos and images at our Lego Ideas Page.
 

[2GodBDGlory]

Super impressive work!

Getting the relatively random gear ratios to work, and then topping it off in such an attractive casing is very impressive!

[howitzer]

Magnificent work! I love the dials at the base and the aesthetics in general, I only hope it would be possible to include the largest moons of the solar system (those of Earth, Jupiter, Saturn and maybe Neptune) but I completely understand the unwieldiness of such machinery. I don't mind dropping Pluto at all, considering its status as a dwarf planet.

Any chance of getting a better look at the inside of the machine, to view the gears at work?

[Jeroen Ottens]

Very nice model. I'd also be interested in a closer look at the insides. Too bad the moon didn't make it, but that might be a discussion to be had with the LEGO designers if you get accepted.

[Seasider]

Great looking model.

would you be able to share an image of the insides just to show the complex mess of gears. Just curious what 153 gears looks like

[Ivorrr]

Poor Pluto 

[Orcman]

The view from above after removing the frame top and the sun

 

The view from underneath

 

Unfortunately the frame hides most of the gearing when viewed from the side.

 

The end-points of the gear-train were fixed, so most of the gearing is mostly arranged in triangles.

[Hrafn]

Very impressive!  Nice to see a collaboration between people with complementary skills as well.

[mdemerchant]

This is really impressive.  Getting such a complicated gear train running so smoothly while moving some fairly large parts is a real achievement but it looks fantastic as well.  Best of luck with you Ideas submission.

[aeh5040]

This is absolutely brilliant, well done!

Very tempting to think that it stands a real chance on Ideas...

[lcvisser]

Wow. Just wow, amazing!  I wish there was some more footage of the mechanisms, without the artistic shots, is that possible? It's mesmerizing to watch... I didn't realize the clocks in the base were moving too; are they matching the orbital periods? How did you get those to match the big rings?

Have you considered putting the planets at a bit more accurate distances with respect to each other? I can imagine it would put Uranus and Neptune so far out that the model becomes unstable, but now it's a bit crowded 

[howitzer]

34 minutes ago, aeh5040 said:

This is absolutely brilliant, well done!

Very tempting to think that it stands a real chance on Ideas...

If there ever was a Technic submission that stood a chance, this would be it. Real life space-themed submissions have done pretty well in the past (ISS, Saturn V, Women of Nasa, Curiosity, Hayabusa) and this one has also similar novelty gimmicks that probably had a significant impact on the approval of sets like the Grand piano or the Typewriter so that might help too.

Still not holding my breath, considering no Technic submission has ever been approved.

Edited September 19, 2021 by howitzer

[Orcman]

1 hour ago, ludovisser said:

Wow. Just wow, amazing!  I wish there was some more footage of the mechanisms, without the artistic shots, is that possible? It's mesmerizing to watch... I didn't realize the clocks in the base were moving too; are they matching the orbital periods? How did you get those to match the big rings?

Have you considered putting the planets at a bit more accurate distances with respect to each other? I can imagine it would put Uranus and Neptune so far out that the model becomes unstable, but now it's a bit crowded 

Yes the dials are moving at the same rate as their respective planet.  To keep the dials sync'd, they each have a 16:140 reduction - same as the drive to outer ring.

Although it looks ok, the outer arms already sag about brick. There is no way to support the arm from underneath.  The Neptune arm is shown in both images below.  The top image is just a single beam supported by the axle-hole.  The bottom image is close to the final design.  The further out you get, the worse the sag becomes.  It was one of the compromise areas.  So a more "in scale" arms would have sagged more than we desired.

If you really re-enforce the arm, that weight then affects the movement and makes the whole thing much "heavier" looking.  The other aspect is working area.  It already needs a 76cm diameter circle to work in.  We were aiming for something that could fit on a desk.

1 hour ago, howitzer said:

If there ever was a Technic submission that stood a chance, this would be it. Real life space-themed submissions have done pretty well in the past (ISS, Saturn V, Women of Nasa, Curiosity, Hayabusa) and this one has also similar novelty gimmicks that probably had a significant impact on the approval of sets like the Grand piano or the Typewriter so that might help too.

Still not holding my breath, considering no Technic submission has ever been approved.

If it was a purely Technic model, I'd probably agree, but I feel that with the design of the base and the planets being much more "Creator Expert" it should have a broader appeal.  I would say that the model is almost a 50-50 blend between a Technic and Creator feels.

So I am cautiously optimistic about our chances.

[Glaysche]

Congratulations on hitting 10,000 supporters! I really hope this makes it through review and becomes a set.  I will be first in line to buy it.

[Axadder]

On 9/19/2021 at 1:13 AM, Orcman said:

The view from above after removing the frame top and the sun

 

The view from underneath

 

Unfortunately the frame hides most of the gearing when viewed from the side.

 

The end-points of the gear-train were fixed, so most of the gearing is mostly arranged in triangles.

This is similar to porn for me.

Seriously considering buying it, which are the dimensions? I´m space-constrained and every cubic meter is gold.

[howitzer]

On 10/5/2021 at 11:39 PM, Glaysche said:

Congratulations on hitting 10,000 supporters! I really hope this makes it through review and becomes a set.  I will be first in line to buy it.

Indeed, if it becomes a set, it's a day 1 purchase for me.

[Glaysche]

The Ideas submission was not approved in review.  It has been resubmitted here:

https://ideas.lego.com/projects/bf7068e7-bd0e-42ae-afe5-dc867b8479d4
 

[Nazgarot]

I would love to buy instructions for this, even if it is only a cad model that I can use to reverse engineer it. 

Please give me a PM if that is possible.

Superb model! And perfect for display. Lego are probably not willing to make it as they see it as to complex... I find it perfect for technic fans!

 

_ED_

[howitzer]

On 7/15/2022 at 4:41 PM, Nazgarot said:

I would love to buy instructions for this, even if it is only a cad model that I can use to reverse engineer it. 

Please give me a PM if that is possible.

Superb model! And perfect for display. Lego are probably not willing to make it as they see it as to complex... I find it perfect for technic fans!

 

_ED_

I believe the IDEAS submission contract forbids any form of selling the model or its instructions for (I think) three years from the submission.

[wissamms]

Supporting also, and hoping to have access to building instructions some day!

[williamyzfr1]

Seriously impressive, I really hope Lego show some interest as I would be one of the first purchasers.

[Davidz90]

Absolutely amazing. Good luck getting approved this time, unfortunately for some reason Technic submissions don't seem to fare well on Ideas.

Great idea with starting from Mercury and gearing down from here, the accuracy is impressive!

[howitzer]

2 minutes ago, Davidz90 said:

Absolutely amazing. Good luck getting approved this time, unfortunately for some reason Technic submissions don't seem to fare well on Ideas.

Great idea with starting from Mercury and gearing down from here, the accuracy is impressive!

Technic notwithstanding, the review results were really baffling this time, as only one was approved and that was about some movie (I think?) franchise which I've never even heard of. And a dozen other very worthy submissions were turned down, this one among them. Anyway, I hope the next time will change that - after all, there has been similar cases of initially rejected and then later approved submissions.

[wissamms]

On 7/14/2022 at 7:13 AM, Glaysche said:

The Ideas submission was not approved in review.  It has been resubmitted here:

https://ideas.lego.com/projects/bf7068e7-bd0e-42ae-afe5-dc867b8479d4
 

We see in the video of the working prototype some vibration of the planets. do you have any idea for reducing this? silicon on all the gears and moving parts to allow a smoother rotation?