42082 - Rough Terrain Crane

[jorgeopesi]

And the steering?.

[Ngoc Nguyen]

3 minutes ago, jorgeopesi said:

And the steering?.

4 wheel steering?

[Jeroen Ottens]

Unfortunately the gears for the LA's are again not mounted correctly (just like on the 42009)... They are mounted in a way that when the boom lifts most load will transfer to one LA.

And it looks like it will not be easy to fix this time.

[Bartybum]

The model in that video is unsettlingly shiny...

[Jockos]

32 minutes ago, Jeroen Ottens said:

Unfortunately the gears for the LA's are again not mounted correctly (just like on the 42009)... They are mounted in a way that when the boom lifts most load will transfer to one LA.

And it looks like it will not be easy to fix this time.

I think some members will find a way to correct it?

Edited July 4, 2018 by Jockos

[Cumulonimbus]

51 minutes ago, Jeroen Ottens said:

Unfortunately the gears for the LA's are again not mounted correctly (just like on the 42009)... They are mounted in a way that when the boom lifts most load will transfer to one LA.

And it looks like it will not be easy to fix this time.

Can you elaborate? I don't really understand what the issue is and I was not aware of a problem in the 42009.

In any case, I'm considering to replace the LAs because their range is too limited for this crane. I would like to see a boom which can rest horizontally during transport and can achieve a bigger angle during lifting . A solution like in the Kenworth K100 Crane Truck of @efferman might do the trick.

Edited July 4, 2018 by Cumulonimbus
Spelling

[TeamThrifty]

4 minutes ago, Cumulonimbus said:

Can you elaborate?

Yea, for me too... i must be missing something?

Overall, i was already looking forward to this set. That video has doubled that!! Looks awesome. Also, there does seem to be a bearing cage inside the turntables, there's some yellow in there rotating at half-speed

[Jockos]

If you place the gears on the opposite site of the other LA, it will cause a little backlash which means that if one of the LAs reaches its end, the other takes more time to do the same. I think.

[mortenm]

I really like this set, but it's a shame that the slewing of the superstructure is not very smooth :(

[Cumulonimbus]

Does anybody have an idea why there are rubber bands in the upper structure? They can be seen in the video from 2:15 onward, in the bottom right hand corner. Looks like a return to center mechanism or a belt-driven axle, but I can't think of a reason why it would be needed there.

Edited July 4, 2018 by Cumulonimbus

[TeamThrifty]

LA's... still not following why the load is on one. Could be just me.. but if they're both 'aligned' to the same length to start with, then aside from slop in the gears, they'll extend at the same rate and share the load. if they start aligned, they'll stay aligned....?

[incognito]

1 hour ago, Bartybum said:

The model in that video is unsettlingly shiny...

That shaky camera is even more unsettling

[Maaboo the Witch]

I like that it actually includes a tool box. The sticker on the panel ain't just for show!

[Erik Leppen]

28 minutes ago, TeamThrifty said:

LA's... still not following why the load is on one. Could be just me.. but if they're both 'aligned' to the same length to start with, then aside from slop in the gears, they'll extend at the same rate and share the load. if they start aligned, they'll stay aligned....?

The thing is, they don't extend at the same rate, because the idler gears of each LA (shown in 3:01 in the video) are on different sides.

The gray 20t idler gera for the left LA is on the right, and the gear for the right LA is on the left. This means that as the LAs rotate, they will move very slightly inwards or outwards. And this means that a length difference will occur when the boom moves up or down. If the LAs are aligned with horizontal boom, they will be slightly at different lengths when the boom is up. The slightly further extended LA will bear the most load.

You can test this by doing a test build, and then insert both 20t idler gears in a single LA bracket. So you get a closed loop of 4 bevel gears (2x tan 12t, 2x gray 20t idler). You will notice that the LA can't move up or down. If the position of the idler gear would have no effect, you could just have the same motions as with a single gear.

Or just do a test build similar to the bulid in the set, and connect the tops of the LAs with axles. You iwll notice that if you rotate the LAs over their mount axis, their lengths will start to de-align.

[TeamThrifty]

I'm with you now! its the boom angle causing the LA's to rotate around their driving axis and effectively extending one and retracting the other... course. Thanks for that!!

[Jeroen Ottens]

32 minutes ago, Erik Leppen said:

The thing is, they don't extend at the same rate, because the idler gears of each LA (shown in 3:01 in the video) are on different sides.

The gray 20t idler gera for the left LA is on the right, and the gear for the right LA is on the left. This means that as the LAs rotate, they will move very slightly inwards or outwards. And this means that a length difference will occur when the boom moves up or down. If the LAs are aligned with horizontal boom, they will be slightly at different lengths when the boom is up. The slightly further extended LA will bear the most load.

You can test this by doing a test build, and then insert both 20t idler gears in a single LA bracket. So you get a closed loop of 4 bevel gears (2x tan 12t, 2x gray 20t idler). You will notice that the LA can't move up or down. If the position of the idler gear would have no effect, you could just have the same motions as with a single gear.

Or just do a test build similar to the bulid in the set, and connect the tops of the LAs with axles. You iwll notice that if you rotate the LAs over their mount axis, their lengths will start to de-align.

That's what I meant. It really is a pity that they didn't take the learning from the 42009.

[Lipko]

Interesting info about the LAs. I had the same setup with my telehandler and I haven't noticed this effect, though the LAs are much further apart in my case, so that might compensate it a bit. A bigger Another problem with this double setup is that when LAs reach their end positions and the inner clucthes engage, the torque when the LAs can start moving into the opposite direction will differ. The more you let the LAs click like crazy, the bigger the difference will be. It can happen that one LA starts to move while the other is still stuck. This will jam the system very soon and the only way to fix it is to dismount the LAs' ends, align their lengths and mount them again.

I noticed tis effect on an exhibiion where I let the kids play with the model for a long time and when kids let the clutched click like crazy. I had to fix the LA's about every hour. Luckily it was simple to do the fix, and it's simple in case of the 42082 too.

I still don't know how to properly fix this issue, my gut feeling says applying a differential between the LAs would be much worse than hard coupling. I don't think that placing th egears on the proper side would fix it. White 24t gears are also much worse since their clutch power is much more unreliable that the LAs.

EDIT: it would be easy to swap side of the idler gear in case of my model, I'll give it a try when I'll have time. Curse my symmetry mania...

 

On the model: it's funny how over-complicated their solution is to enfore one way switching of the battery box. It could be done with like 4 pieces instead of 9.

 

Edited July 4, 2018 by Lipko

[mortenm]

1 hour ago, Jeroen Ottens said:

That's what I meant. It really is a pity that they didn't take the learning from the 42009.

It was the same on 8043 as I recall.

[AVCampos]

Yes, the issue was first identified in the 8043. I didn't know the 42009 had it as well.

[896gerard]

The video shows a rotating superstructure... not swiveling in a smooth way. I found this pulsating behaviour with an XL motor under a too heavy load. Of course, the superstructure is really heavy but in this model they have a high-quality turntable at their disposal! 

[AVCampos]

It's possible that this is due to unbalanced U-joints at steep angles in the slewing mechanism:

 

Edited July 4, 2018 by AVCampos
Added video

[TeamThrifty]

or maybe the bearing arrangement caused grip/slip friction? Still love it and can't wait to get it.

[Ngoc Nguyen]

4 hours ago, Cumulonimbus said:

Does anybody have an idea why there are rubber bands in the upper structure

I think they are parts of a clamping mechanism that holds either the batterbox or the 5x7 panel lid.

Edited July 4, 2018 by Ngoc Nguyen

[Aleh]

7 hours ago, Ngoc Nguyen said:

In action:

My guess about the B model was right!

Wow, thanks for sharing! Such attention to a small things like a toolbox with tools, oil filter, perfect!

[Maaboo the Witch]

2 hours ago, Aleh said:

Wow, thanks for sharing! Such attention to a small things like a toolbox with tools, oil filter, perfect!

It's what a flagship set - nay, a Technic set - deserves.