[TC25] 42082 Rough terrain crane

[Akassin]

I am very surprised that I am the only one who has chosen the 42082 set so far, but I think this will change 
So, I chose the scale of the wheels 49.5mm. This will make the crane much smaller (about 2x) but keep all the features of the original (I hope to keep the gearbox of the original set, so that you can control the model with a single rotating element, which will be in place of the motor, but not sure if it will be enough yet place for it).

I just started working, so I just created a dimensional layout that will show how much free space I have inside.

[JoKo]

Good start!

I didn't even try to keep the gearbox on my Osprey but for a crane this could add to playability and maybe a few more points for staying mechanically true to original.

[TechnicMOCer]

Looks pretty cool so far, looking forward to see new progress

[Jundis]

Thought about making this model for the contest, too. 4-wheel steering AND the fake motor will be challenging to integrate into the small bundle. Gearbox will be a tight fit, too.

Will follow this with great interest :-)

[arijitdas]

I too have this on my radar but i may not be able to complete this within the timeline for the TC25. So i might post my progress as and when i start working on it. This will definitely be an interesting build to follow.

[lcvisser]

The first picture has different wheels than the second? Looks like 62.4x20.

[Akassin]

5 minutes ago, lcvisser said:

The first picture has different wheels than the second? Looks like 62.4x20.

Yes, it's just an image of a 62.4 wheel that has been reduced to size 49.5. This is a graphic editor and not an application with real lego elements, so I use the images that I had.

[lcvisser]

Ah ok, I see. I was worried you did  the scaling based on 62.4 and then build with 49.5, but I didn’t realize you scaled the image. Carry on ;-)

[lmdesigner42]

That's an ambitious amount of shrinkage! Rough-terrain cranes are difficult to model because their real-life counterparts are already so compact. I can't wait to see what solutions you come up with.

[Akassin]

so some progress

I guess I was able to keep the functionality of the lower part of the original set. Now only the front part is assembled from real lego parts, and I hope that the rest will also be able to be assembled without any special "surprises"

completed:
- gear box driven from the top of the crane and controlled by switches on the sides like the original set (turret slewing and outrigger operation)
- four-wheel drive with all swivel wheels with HOG in the back
- fake engine

to be continued ...

[Akassin]

After a long break, I'm ready to show the build progress. I had little time, but the task turned out to be much more difficult than it seemed in theory.
When I started designing the bottom, I thought that just 2 features (outriggers and top rotation) shouldn't cause many problems. And I didn't worry at all about all-wheel drive with a fake motor hooked up and all four wheels turning. How wrong I was... 
When the time came for the actual assembly, I realized that there was absolutely not enough space. And the biggest problem was the four-wheel drive engine. I redid the design about 10 times until I managed to fit everything inside.
At this point, I was very worried about the strength of the structure. Because there are areas where there are no beams at all, and the entire space is occupied by a gearbox and other gears.
But when I finished the assembly - I calmed down. The construction is very solid. You can take one edge and even if you shake it, there will be no bends (the original model has a large bend in the center)
So, the lower part is completely finished and has retained all the functions of the original model except for one (the opening tool boxes are dummies, because there is no storage space left inside).
Now I moved on to designing the top.

[Jurss]

Impressive build for the scale

[SaperPL]

Nice progress. Is everything driven through that 20T gear at back that is offset to the left? By everything I mean steering, outriggers, rotation of the turntable and that input inside the turntable?

I don't like the design of the engine though - half bushings attached halfway at the end of the axle feels like something that will definitely get loose.

Also the knob being asymmetric might be weird when driving, but more importantly I think it should stick outside of the outline of that system rear lights assembly to be ergonomic. I would expect there would be a lot of cranking done with this, so it should be done ergonomically.

[Akassin]

Thanks for the feedback guys

1 hour ago, SaperPL said:

Nice progress. Is everything driven through that 20T gear at back that is offset to the left? By everything I mean steering, outriggers, rotation of the turntable and that input inside the turntable?

I don't like the design of the engine though - half bushings attached halfway at the end of the axle feels like something that will definitely get loose.

Also the knob being asymmetric might be weird when driving, but more importantly I think it should stick outside of the outline of that system rear lights assembly to be ergonomic. I would expect there would be a lot of cranking done with this, so it should be done ergonomically.

This gear only controls the steering. The outriggers and the turntable will be driven through the center axle in the turntable. The rotating element (engine replacement) that will need to be rotated and by which all mechanisms will be controlled will be located in the upper superstructure (the original set has an L-motor there)

About the fake engine: this idea does not belong to me. This is the most compact V-engine I could find. Any other option with an axis length of 3 or more - does not fit inside. I understand that such a solution would never be applied in an official Lego set, but here it works (in fact, they have not fallen off even once, despite the fact that I constantly twist the model in my hands during assembly). I've lost  wheels a few times on sharp turns, but the half-bushings stayed where they were :) 

About the location of the knob. My inner perfectionist was furious when I had to place it off-center . But due to the fact that the fake engine had to be exactly in the center - I could not find another solution. Because it controls only the rotation of the wheels - it does not need to be rotated much (the wheels make a full turn in half a turn of the knob). But if it becomes difficult when the top of the crane is added, I can easily move it a little further.

In addition, here is the summary of tonight.
Pre-placed all gears and gearboxes. Started designing the top.

 

[SaperPL]

7 hours ago, Akassin said:

About the fake engine: this idea does not belong to me. This is the most compact V-engine I could find. Any other option with an axis length of 3 or more - does not fit inside.

I've built a fake engine at this scale this way:

There is still some travel on those fake pistons in this kind of construction.

[Akassin]

33 minutes ago, SaperPL said:

I've built a fake engine at this scale this way:

There is still some travel on those fake pistons in this kind of construction.

I saw your version, it is compact and very reliable . But I would like the half bushings to be on the outside. To mimic cylinder heads.
To get the same result as in your version, I can simply remove them.

[Jundis]

Also another favorite model for me! Impressive to get all the mechanics in there :-)

To get the yellow, you can maybe use the crankshaft piece upside down: 

Not sure if it twists inside and maybe block the shaft?

[Thirdwigg]

Another great build @Akassin, and so many functions in this dense build. I look forward to see how the superstructure turns out.

[Akassin]

@Thirdwigg, @Jundis, Thanks!

Some progress. Now I need to assemble the upper part from real bricks and test the operation of all gearboxes. Next - crane boom and driver's cab

Well, the comparison with the "big brother"

mechanisms inside

Edited August 2, 2023 by Akassin

[Frequenzberater]

That is pretty cool. Awesome work so far. Iam impressed by the density of mechanisms 

[lcvisser]

This contest is producing a lot of awesome entries with very high density builds, but indeed this one is particularly complex. Amazing how much you manage to fit in there!

[MangaNOID]

nice!

I could never afford this one at the time and probably still don't want anything that big so this little one is exciting. well done for cramming it all in.

the small steering quirk pointed out before seems no big deal for something this compact and full of functions. Very forgivable!

Although your missing one thing...a chassis full of rainbow 

[mdemerchant]

This really is super impressive.  42082 is one of my favorite sets and I wouldn't have thought it possible to replicate so much of the mechanics in such a small size.  Very well done so far.

[Jundis]

Again, a brilliant model. This contest really is gold!

I knew that the original model had the forward/backwards function as the motor only turns one way. But for a hand-cranked model the reverse mode for every function is a little bit of an overkill :D

Also leads to much slack :-P

[nerdsforprez]

Crimony.  Well done.  And for what it is worth, I like the engine the way it is....