42131 - CAT D11 Bulldozer

[jorgeopesi]

Why not 8043 set up?, one motor change the functions of the others. For example first gear - left track, right track and ladder, second gear - ripper, pitch and lift blade.

[suffocation]

4 minutes ago, jorgeopesi said:

Why not 8043 set up?, one motor change the functions of the others. For example first gear - left track, right track and ladder, second gear - ripper, pitch and lift blade.

The model's probably too heavy to work safely (i.e. parts not breaking) and effectively with that kind of setup.

[Bricksley]

22 minutes ago, suffocation said:

The model's probably too heavy to work safely (i.e. parts not breaking) and effectively with that kind of setup.

In 8043 & 42042 it work so slow, soo what it will be in set that size? Nothing good.

[jorgeopesi]

32 minutes ago, suffocation said:

The model's probably too heavy to work safely (i.e. parts not breaking) and effectively with that kind of setup.

That is why I do my MOCs as small as possible... Lego Technic is seriously affected for the weight and for the price  .

[Ngoc Nguyen]

4 minutes ago, jorgeopesi said:

the weight and for the price 

What goes up and never goes down? 

Edited August 23, 2021 by Ngoc Nguyen

[AVCampos]

11 minutes ago, Ngoc Nguyen said:

What goes up and never goes down? 

Hopefully not landing gears.

[gyenesvi]

2 hours ago, Ngoc Nguyen said:

If all functions can work in both directions, then the wave selector will engage in two functions at the same time

I don't get how the function directions and what the wave selector engages would be related to each other. It's completely independent. The direction is determined by the motor direction set by the app (not by the gearbox; could be but it would be complicated and wasteful). The wave selector needs to engage one function at a time to be able to control every function independently (in both directions). One wave selector can only select between 4 functions, since it engages in 90 degree rotations, after 4 such rotations it gets back to the first position.

[JaBaCaDaBra]

2 hours ago, M_longer said:

The gearbox works as in 42114 - only one function at the time.

Did you alleady build it?

[J159753]

I did love some of those classic Technic sets where the direction of the motor would chose the function selected, via a floating cog. Inappropriate in a set this vast, but a marvel of elegant, efficient design in those resource-constrained sets of old...

[Ngoc Nguyen]

47 minutes ago, gyenesvi said:

I don't get how the function directions and what the wave selector engages would be related to each other.

 

 

2 hours ago, suffocation said:

But if there are four motors in all, with two for the tracks and one for the wave selector, that leaves only one motor to drive the functions, ergo only one can be driven at a time (in addition to the tracks, of course).

 

I was thinking of a setup like this.

Edited August 23, 2021 by Ngoc Nguyen

[M_longer]

9 minutes ago, Ngoc Nguyen said:

I was thinking of a setup like this.

42114 setup. Two driving rings, motors side to side.

Edited August 23, 2021 by M_longer

[Void_S]

53 minutes ago, Ngoc Nguyen said:

I was thinking of a setup like this.

This scheme will work a bit differently to "only one can be driven at a time". I have built it (great idea btw) and it has the following sequence of "engages":

1. 45/135/225/315-degrees position
   1. Clutch #1 = idles
   2. Clutch #2 = idles
   3. Clutch #3 = idles
   4. Clutch #4 = idles
2. 0-degrees position
   1. Clutch #1 = engaged to "positive" side
   2. Clutch #2 = idles
   3. Clutch #3 = engaged to "negative" side
   4. Clutch #4 = idles
3. 90-degrees position
   1. Clutch #1 = idles
   2. Clutch #2 = engaged to "positive" side
   3. Clutch #3 = idles
   4. Clutch #4 = engaged to "negative" side
4. 180-degrees position (inverted 0)
   1. Clutch #1 = engaged to "negative" side
   2. Clutch #2 = idles
   3. Clutch #3 = engaged to "positive" side
   4. Clutch #4 = idles
5. 270-degrees position (inverted 90)
   1. Clutch #1 = idles
   2. Clutch #2 = engaged to "positive" side
   3. Clutch #3 = idles
   4. Clutch #4 = engaged to "negative" side

There are always two outputs out of 8 are engaged, or (if 45-inclined are allowed) all are disengaged.

[gyenesvi]

1 hour ago, Ngoc Nguyen said:

I was thinking of a setup like this.

The way you are showing this here (clutch gears only on one side, I guess that's intentional) allows them to be independent (@Void_S, what you are saying would apply with clutch gears on both sides of the driving ring I guess), but this setup has only 4 outputs (all of them can go in two directions though). However, the same 4 outputs can be achieved with a simpler setup, with only 2 driving rings like in 42114, as @M_longer says. And I don't see how such a RC gearbox could even in theory be scaled up to more than 4 independent outputs. So I guess that's why it will only have 4 functions apart from driving.

4 hours ago, jorgeopesi said:

Why not 8043 set up?

I think even if the weight was not a problem, it would still not work out for the play experience. The reason is that in 8043, you don't want to drive and dig at the same time, so it's okay that you need to switch between them. However, with a bulldozer, you probably do want to move the blade/ripper while driving it, so it's not okay that you can't control them simultaneously.

[Void_S]

1 minute ago, gyenesvi said:

what you are saying would apply with clutch gears on both sides of the driving ring I guess

Exactly, left or right sides.

[JaBaCaDaBra]

1 hour ago, Void_S said:

This scheme will work a bit differently to "only one can be driven at a time". I have built it (great idea btw) and it has the following sequence of "engages":

1. 45/135/225/315-degrees position
   1. Clutch #1 = idles
   2. Clutch #2 = idles
   3. Clutch #3 = idles
   4. Clutch #4 = idles
2. 0-degrees position
   1. Clutch #1 = engaged to "positive" side
   2. Clutch #2 = idles
   3. Clutch #3 = engaged to "negative" side
   4. Clutch #4 = idles
3. 90-degrees position
   1. Clutch #1 = idles
   2. Clutch #2 = engaged to "positive" side
   3. Clutch #3 = idles
   4. Clutch #4 = engaged to "negative" side
4. 180-degrees position (inverted 0)
   1. Clutch #1 = engaged to "negative" side
   2. Clutch #2 = idles
   3. Clutch #3 = engaged to "positive" side
   4. Clutch #4 = idles
5. 270-degrees position (inverted 90)
   1. Clutch #1 = idles
   2. Clutch #2 = engaged to "positive" side
   3. Clutch #3 = idles
   4. Clutch #4 = engaged to "negative" side

There are always two outputs out of 8 are engaged, or (if 45-inclined are allowed) all are disengaged.

PF L motors have no positions

30 minutes ago, gyenesvi said:

probably do want to move the blade

Chances are that with the advanced functions of PU there will be an auto leveling.

[Ngoc Nguyen]

3 hours ago, M_longer said:

42114 setup. Two driving rings, motors side to side.

It wasn't until a few minutes ago that I actually understood how the 42114 gearbox works, since I've never owned the set. I've just built its gearbox in Studio. Its setup is more compact than the one I posted earlier .

[gyenesvi]

43 minutes ago, JaBaCaDaBra said:

PF L motors have no positions

Who said PF L motors? The set will come with PU motors. @Ngoc Nguyen's build was just an illustration.

44 minutes ago, JaBaCaDaBra said:

Chances are that with the advanced functions of PU there will be an auto leveling.

What do you mean by that? Auto levelling of what? The blade?

[jorgeopesi]

1 hour ago, gyenesvi said:

I think even if the weight was not a problem, it would still not work out for the play experience. The reason is that in 8043, you don't want to drive and dig at the same time, so it's okay that you need to switch between them. However, with a bulldozer, you probably do want to move the blade/ripper while driving it, so it's not okay that you can't control them simultaneously.

It is not a problem, you can drive and lift the blade at the same time and the ripper, ladder and pitch functions are movements that do not need to use while you are driving specially the ladder  . Another option would be two motors for tracks even using a subtractor, one motor for all the functions and the other one for the gearbox so you could drive and use one of the functions you want at the same time.

The weight it will be a problem for sure, you just have to watch the liftarm off the upper sprocket to know it and I even do not know if it is the drive sprocket as it should have to be...

Edited August 23, 2021 by jorgeopesi

[AVCampos]

Or it could have two such mechanisms, using a single motor for selection: that way the model could have 8 functions, two at a time, using 3 motors.

[suffocation]

7 minutes ago, AVCampos said:

Or it could have two such mechanisms, using a single motor for selection: that way the model could have 8 functions, two at a time, using 3 motors.

Indeed. I used this mechanism for my cherry picker and it works flawlessly; then again, the model only weighs 1.8 kg, whereas the CAT probably weighs at least twice as much.

[gyenesvi]

1 hour ago, jorgeopesi said:

Another option would be two motors for tracks even using a subtractor, one motor for all the functions and the other one for the gearbox so you could drive and use one of the functions you want at the same time.

That's pretty much how it's going to be (except the subtractor), but since it'll have an auto gearbox, you won't have to switch manually, the app will do that, so you will be able to use all functions while driving, but not at the same time, just one by one (but any one of them). I wonder how many fingers you'll need for that though..

1 hour ago, jorgeopesi said:

It is not a problem, you can drive and lift the blade at the same time and the ripper, ladder and pitch functions are movements that do not need to use while you are driving specially the ladder

I agree about the ladder :) Not sure about the rest..

1 hour ago, AVCampos said:

Or it could have two such mechanisms, using a single motor for selection: that way the model could have 8 functions, two at a time, using 3 motors.

That's of course a possibility, but that would require 5 motors, and you probably don't want to add one more hub just for the 5th function.

[suffocation]

5 minutes ago, gyenesvi said:

but that would require 5 motors

Nope, you just need three motors for eight functions driven in pairs.

[gyenesvi]

1 minute ago, suffocation said:

Nope, you just need three motors for eight functions driven in pairs.

Sure, and together with the two motors for drive (as is in this set, confirmed above by @M_longer), that would amount to 5 motors. Or are you saying the 8 functions could already include the drive? Then you hit the same problem I mentioned above (can't drive and move the blade at the same time).

[suffocation]

13 minutes ago, gyenesvi said:

and together with the two motors for drive

Ah, I see what you mean now. Yes, that would indeed be the issue - with three motors driving all the functions, including drive (which in the case of a tracked vehicle counts as two functions), you couldn't move the blade while driving. I guess it's a solution that works fine with models where you aren't likely to use more than two functions at a time (e.g. tow trucks and cherry pickers), but becomes kind of awkward with tracked machinery.

[eric trax]

Oh guys. I know it's hard to believe that such an expensive set has only one hub and four engines. Finally, Lego sells kits only for a fair/low price, right??? Be brave :)

- 2x Large Angular motor separately for each track without connection to the gearbox.

- 2x Large motors: First one drive functions, second one for operate a gearbox similar to the 42114 (four positions) to control four functions: Blade Lift, Blade Tilt/Pitch, Ladder Lift and Ripper Lift - only one at a time