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lindr6

[TC8] Grove Shuttlelift CD3339

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Grove Shuttlelift CD3339:

22533729182_1e4ee8816a_o.jpg

(This is the 3340 version, not the 3339, but they are very similar)

My inspiration for this little crane is that I see it working on a bridge crossing the Mississippi river on my commute to work. It is constantly busy lifting this and that down to the crews working below the road deck. The first time I saw this little crane, I instantly knew I wanted to model it in lego technic, so I added it to my list of MOCs to create. This contest was just what I needed to convince me to start the project.

Here is my version of this little crane, in 1:10 scale:

22359342060_5c363af8f6_c.jpg

22359553898_f923f3a058_c.jpg

Here are the functions:

  • 1 Servo motor for 4 wheel steering (also turns the steering wheel in the cabin).
  • 1 XL motor powering the wheels. This thing is 4 wheel drive implemented using 3 differentials
  • 1 Large motor for lowering the four stabilizers (one on each corner).
  • 1 Medium motor for rotating the boom structure.
  • 1 Large motor for raising/lowering the boom.
  • 1 Medium motor for extending the boom.
  • 1 Medium motor powering the winch to raise/lower the hook.
  • 1 PF Lights used for headlights.

More pictures and a video to come. I also plan to share some retrospective on this build.

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That is a really cool crane! But how much weight can it take, because it looks like the mount for the 'superstructure' is rather thin

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That is a really cool crane! But how much weight can it take, because it looks like the mount for the 'superstructure' is rather thin

Agreed, but as mentioned in the rules of the contest, lifting lots of weight, or even ANY weight, is not really a goal of the contest. Not that I agree with that, because I don't, but I don't think that judges will be really concerned with weight the cranes can lift. I posited the idea of perhaps using third party weights (weight other than battery boxes) as legal for the competition.... and it was frowned upon. Kinda weird, because technically, all battery boxes have third party weights (TLG does not produce AA batteries). Without weight, the amount of weight Lego cranes can lift will be minimal, even if superstructures, etc. are strong. Edited by nerdsforprez

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That is a really cool crane! But how much weight can it take, because it looks like the mount for the 'superstructure' is rather thin

This model was not built with the intention to match the ability of the real version, but to match the functions and overall look. I actual spent a lot of time to balance the boom and counterweight on top of the turntable so that it stays pretty balanced with varying boom heights and extension. With that said, I was testing by lifting a battery box which it handles with ease.

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Here is the video:

Retrospective:

This was the first crane MOC that I have attempted, and it had some unexpected successes and challenges.

  1. Using the big unimog wheels takes a lot more room than expected for all the steering sweep. I needed to keep the wheel arches close to the wheel to match the real crane, so there is a lot of empty space under the body, which left limited room for the motors and gearing.
  2. I knew the large turntable is not the most stable part, especially when a lot of weight is placed on it, but I did not expect to have to spend so much time balancing out the boom and counterweight to keep from having too much weight and lean on the turntable. The final version turned out well, and I assume the real crane has careful planning around this as well.
  3. A two stud wide outrigger that comes out at an angle that is capable of handling the weight of the entire model. It was tough to keep the mechanics and outrigger down to 2 studs wide (3 if you count the panel on one side), yet keep it strong. Only two studs were permitted because of the large tire sweep for the wheels.
  4. Clutch gears, it was tough to work in a clutch gears for all the different gear trains. That gear is just too big to fit nicely in any tight space. It would be great if Lego were to crate a smaller one. Anyways, I was able to work it in, just took much more effort than expected.
  5. Boom extension works great using the super long axle from the mobile crane going through all the panels. This allowed a more sleek boom that matched the real model, and prevented the need for an externally exposed axel. I'm happy with how this turned out.
  6. I was uncertain how the large LA would handle picking up the heavy boom when mounted at the angle as the real machine. To my surprise, it works great and I did not have any issue with it!
  7. I wanted to do a second steering mode for the crab steering, but as usual, time is not on my side, so this feature has not been implemented. This is an optional feature on the real model, so I am good with not adding it, but would have been nice. I should have started with it implemented as I developed the steering and drive mechanics of the model, instead of skipping it so that I could be sure to have plenty of time to work out any problems with the rest of the model. Perhaps I will continue to work on the model after this contest to work it in.
  8. I wanted to have full 360 degree rotation of the boom, and not worry about wires, gear, and hoses getting tangled up, but I also wanted just one battery box to keep the model as light as possible. At the end of the day, I ended up using the two battery boxes, one in the boom counterweight, and one in the body. This arrangement allows the freedom of unlimited 360 degree rotation, which was of a higher priority than saving weight. This also simplified all the gearing and whatnot needed to make all the functions work remotely.
  9. I wanted to work in a fake inline 4 cylinder engine into the model. I just could not find/make the room to work it in. The wheel sweep is just too large to allow room for it. If I were to completely redesign the model there might be a chance to work it in, but as usual, the time factor is just not on my side for this. Again, this might be something I try to add if I continue to work on the model.

Thanks for any comments on the model, it was a lot of fun to create. I'd also like to thank the organizers of TC8, as if it were not for this contest to motivate me, this model would still just be on my list of things to MOC.

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Hello Kyle,

I like your Shuttlelift... Nice solution. I like also the outridgers...

Can you tell me more to point 5. ? I'm interested how exactly have you used the long axle to extend the 2nd section. If you got any pictures from WIP to better understand it I will be thankfull... Thank you... :)

Very good work...

Max...

Edited by MaxSupercars

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Can you tell me more to point 5. ? I'm interested how exactly have you used the long axle to extend the 2nd section. If you got any pictures from WIP to better understand it I will be thankfull... Thank you... :)

Hopefully this picture helps. Basically having the really long axle run through the panel pieces to work a worm gear the extends the boom.

22607005545_81f7c8eacf_b.jpg

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Reading your answer only now... Thank you for answer... Nice solution that hides the axle... I got 8 such 32L axles no problem... Thanx...

Max...

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