Jeroen Ottens

[WIP] Lexion Combine harvester

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Hi,

Time for another WIP topic. This time an agricultural machine. The Claas Lexion combine harvester:

280254_01_cid_lexion_8900_designanmeldun

So far I have only worked on the rear axle and the front Terra Trac:

51396996862_03620481ce_c.jpg

Now before I commit myself to the dimensions, I was wondering whether someone with more knowledge about these machines (@eric trax ? )can help a bit on the dimensions. My current axle is 29 studs wide (in the rear) and 30 studs wide at the tracks. But I absolutely have no feeling whether this is sort of ballpark OK with the big tractor tires.

The current rear axle is driven, has pendular suspension, difflock and Ackerman steering. The tracks will also be driven and the gear train will have a 2 speed gearbox (just like the real one) that drives the central differential. I plan to stuff this thing to the max with functions, probably using one or maybe two hubs. I plan to get some nice SW features in there as well, such as automatic engaing/disengaging of the difflock depending on the steering angle and speed.

At the moment I do not envision the use of pneumatics, as they are relatively expensive in terms of motors to switch (unless of course I can think of a way to use a gearbox to switch the pneumatic valves, so that I would only need three motors to switch eight valves... hmm... walks away mumbling to himself...)

As I also have a lot of other commitments progress will be slow though.

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At first sight the proportions between tracks and wheels look good, it will be a big MOC but with a lot of space for mechanisms.

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If it helps, I also work on terrarrac version, but on Jaguar and my choice is very similar to yours giving 1:15 scale in my case. Generally narrowest terrarrac is 349cm (with 635 mm tracks) and widest is 399cm. Wheelbase is good question, since look for this info few years...  standard rear tires 500/85R34 (175cm - perfect for 1:16.5 scale).

My suggestion is to use sariels scaler.

...if you want to make 1:16.5 model minimal width od rear axle is 26 studs including tires...

Looks very very nice (Nowi know that I'm not that far off rough proportions :laugh:

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Looks great already! Just curious, do you think the front tracks will have any issues rolling on hard surfaces if it is not powered? I guess if most of the weight is on the center two small wheels of each then it should not cause any issues?

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I very much enjoy your builds, and recently you have started to share your process as well. I look forward to see how this turns out, and look forward to watching it come to fruition. 

Edited by Thirdwigg

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1 hour ago, sawyer klegr said:

Looks great already! Just curious, do you think the front tracks will have any issues rolling on hard surfaces if it is not powered? I guess if most of the weight is on the center two small wheels of each then it should not cause any issues?

It sounds like he is planning on powering it, but my understanding was that there would be a central differential to split power between the tires and the tracks equally. If this is true, I can see annoying situations where all power is transmitted to slipping plastic tracks. The rubber track inserts could help a fair bit, though.

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On 8/23/2021 at 7:32 PM, 1gor said:

If it helps, I also work on terrarrac version, but on Jaguar and my choice is very similar to yours giving 1:15 scale in my case. Generally narrowest terrarrac is 349cm (with 635 mm tracks) and widest is 399cm. Wheelbase is good question, since look for this info few years...  standard rear tires 500/85R34 (175cm - perfect for 1:16.5 scale).

My suggestion is to use sariels scaler.

...if you want to make 1:16.5 model minimal width od rear axle is 26 studs including tires...

Looks very very nice (Nowi know that I'm not that far off rough proportions :laugh:

I’ll be not supertight on the scale, so the rearaxle is probably a bit too wide

On 8/23/2021 at 8:16 PM, TeamThrifty said:

Already i am excited to see this moc develop!

this may help with dimensions... https://www.ritchiespecs.com/model/claas-lexion-570-plus-terra-trac-combine

 

Thx. I also found a brochure with front view with dimensions. My rear axle is a big too wide, but the frontaxle is really much too wide. Should be 5 studs smaller.

I’ll compromise on 4 studs less wide.

2 hours ago, sawyer klegr said:

Looks great already! Just curious, do you think the front tracks will have any issues rolling on hard surfaces if it is not powered? I guess if most of the weight is on the center two small wheels of each then it should not cause any issues?

Hmm.. good point, hadn’t thought of that…

The small wheels have pendular suspension, I forgot to mention.

2 hours ago, Thirdwigg said:

I very much enjoy your builds, and recently you have started to share your process as well. I look forward to see how this turns out, and look forward to watching it come to fruition. 

Thx I’ll try to regular update

1 hour ago, 2GodBDGlory said:

It sounds like he is planning on powering it, but my understanding was that there would be a central differential to split power between the tires and the tracks equally. If this is true, I can see annoying situations where all power is transmitted to slipping plastic tracks. The rubber track inserts could help a fair bit, though.

I have couple of these rubber studs, that should help indeed.

All wheels and tracks are powered, but only the rearaxle has a difflock (so far). I actually don’t know how ghe real drivetrain is done, but I assumed it would be all wheel/track drive. If anybody knows (especially if there are more difflocks I’d be interested to know.

I have been playing a bit with the motorlayout and the 2-speed gearbox. I realized that I can add two more functions that are driven by the XL drive motor, but these functions will only work when the vehicle is not moving. Any suggestions?

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So far I know axles have hydrostatic drive like here images?q=tbn:ANd9GcTWqensT3e_EYovkcA7j3E

Only terrarrac has something like portal axles hub at the end to transmit power lower since central line of terrarrac system is much lower than on wheels. Then with axles power is transmitted on terrarrac system between wheels (there are actually 8 wheels), but I think your concept is best compromise. :thumbup:

I have tried to add suspension, but at end only thing that worked is suspension like on rear axle of set 42122

 

 

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On the Jaguar Terra Trac, the front idler is lifted during turning to reduce the area. Not sure if the Lexion also has this feature, though:

 

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1 hour ago, Jundis said:

On the Jaguar Terra Trac, the front idler is lifted during turning to reduce the area. Not sure if the Lexion also has this feature though.

Ooh, that is a nice feature… That will be a challenge to make robust, but I like it a lot. Ideally I would like to couple it mechanically to the steeringaxle.

I then just have to figure out a way to turn a two directional proportional input to a one directional digital output.

Two directional to one directional is easy, but proportional to digital is more challenging.

Thinking out loud it will need to be able to take some load when in the down position, so the lifting mechanism will probably be a knee-mechanism (which unfortunately does have a cosine like behaviour for small inputs, whereas ideally you would like to have a sine like behaviour at small inputs to get some lifting action at small angles).

Compromise would be to make the lifting proportional with the steering. So a little lift at small steeringangles and a bigger lift at large steeringangles.

thanks for the suggestion!

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I just finished building a Claas lexion 8900 by Kneisibricks on rebrickable. It was an amazing build but when I saw that you are starting a new project I was interested. I have built most of your moc’s and will follow this. I’m sure it will be great!

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2 hours ago, AFOLegofan66 said:

I just finished building a Claas lexion 8900 by Kneisibricks on rebrickable. It was an amazing build but when I saw that you are starting a new project I was interested. I have built most of your moc’s and will follow this. I’m sure it will be great!

That is a high bar that has been set! What a beauty :wub:. I hope that my development time doesn’t need to be three years before it is finished though :laugh:.

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Nice base indeed, good luck with the MOC, as per real machine the rear set of wheel is i guess 710/60 R30 or 750/65 R26 after some math which i hope i done right you are somewhere in 1:15 scale, so i would adapt everything to this number. and you will be good. 

wish you manage to get "universal" scale of 1:17 to fit all his models. would look great together.

anyway once again good luck, looking forward for this :) 

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7 minutes ago, mktechniccreations said:

Nice base indeed, good luck with the MOC, as per real machine the rear set of wheel is i guess 710/60 R30 or 750/65 R26 after some math which i hope i done right you are somewhere in 1:15 scale, so i would adapt everything to this number. and you will be good. 

wish you manage to get "universal" scale of 1:17 to fit all his models. would look great together.

anyway once again good luck, looking forward for this :) 

710/60R30 and 750/65R26 are usually on Jaguar harvester (that is why I adapted my MOCs to 1:15 for Unimog and Fastrac and after babysitting 6 week old kitten, I'll continue to work on Syn-Trac 1:15).

Just few lines above "LEXION 8000/7000 models at a glance"  you can see that on Jeroen's chosen version 8900 there are 1.75m rear tires - perfect for 1:16.5 scale like typical Lego truckswith 19 studs wide  chassis.

https://www.claas-group.com/press-corporate-communications/press-releases/lexion-8000-and-7000--new-high-performance-combine-harvesters-with-up-to-790-hp/2028102

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On 8/23/2021 at 8:14 PM, Jeroen Ottens said:

I was wondering whether someone with more knowledge about these machines (@eric trax ? )can help a bit on the dimensions.

Well. The 107 tires you choose, compared to the wetness of your Terra Trac, are the largest size (by my eye). These are the equivalents of 500/85 R 34 tires with a diameter of 1750 mm. This is a scale of 1: 16.5 as mentioned in @1gor. Technic links are equivalent (on this scale) to 635mm tracks. This gives a total width of 3490mm. Lego tires are a bit wider than the original ones so I wouldn't change the width of the rear axle and built all the elements to the width of 27 studs.

 

Below, I have scaled the basic elements based on the 360 view available on the manufacturer's website. Here you will find all the basic dimensions you should follow. Select the rest that like it looks just good due to the shape of the bricks. Hope this will be helpful :)

 

d72cf7cbda8b76f2acc03035259d8349_1.jpg

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Thanks @1gor and @eric trax for the scaling info. I’ll probably will not be superaccurate with the scaling, but the broad dimensions should be OK I think.

I am currently away from my bricks, so no design update.

I have however spend some time thinking about the motor configuration. The first constraint I set myself was that I don’t want to use more than two hubs.

Drive needs to have it’s own XL motor as this will be a heavy model. I might couple a fake engine and the fan in the top to this motor as well.

Steering and lifting the front idler will be done with an L motor.

I then have another eight (!) functions to add:

switching high/low gear (1p)
Lock differentials (2p)
Rotate unloading pipe (3p)
Open top hatch (4p)
Raise header (5p)
Raise reel (6p)
Dispense grain (7)
Harvesting functions (8) ie all the conveyor belts, trashing units etc.

The functions with a ‘p’ in brackets could be done with pneumatics.

The only way to drive eight functions without using three hubs is by using a gearbox. That requires one L motor to rotate a wave selector that is surrounded by four driving rings.

In each position the wave selector engages two clutchgears. By using two motors to drive the functions you can get eight functions with just three motors.

If I would use pneumatics the function gearbox all but two of the outputs go to pneumatic valves. I would probably want a separate L motor to drive a pneumatic pump as well then.

Since only two functions can be operated at the same time the high/low gearswitch and the difflock must be a pair.

So at a minimum I now need five motors. I may need a sixth for a pneumatic pump and probably it is wiser to have all the harvesting functions on a separate motor as well, so that makes seven motors.

Now the question to you fellow Eurobrickers is:

should I make this an RC pneumatic combo with six RC pneumatic functions or should I keep everything electrical?

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That is very ambitious. I think for the first time in my life I'll copy some of your ideas if it would be better for my Jaguar project (that would be prolonged because now I sleep 3 time per day for 2 hours, play with 6week old kitty several hours a day, feeding her, etc...and she must be kept worm; vet says it is a little princess). My solution was to use one PF m-motor on rear axle for steering and one extra to lift front idlers, but could not synchronize that, so I abandoned idea and since 1:15 model is heavy I have skipped front terrarrac suspension, just on real axle like on 42122 set has at the rear with yellow shocks).

I'm honored if I can help and  made any kind of contribution to your project.

I would keep everything electrical, but it is my point if view mainly based on what I plan for my Jaguar harvester

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On 8/27/2021 at 9:04 PM, 1gor said:

710/60R30 and 750/65R26 are usually on Jaguar harvester (that is why I adapted my MOCs to 1:15 for Unimog and Fastrac and after babysitting 6 week old kitten, I'll continue to work on Syn-Trac 1:15).

Just few lines above "LEXION 8000/7000 models at a glance"  you can see that on Jeroen's chosen version 8900 there are 1.75m rear tires - perfect for 1:16.5 scale like typical Lego truckswith 19 studs wide  chassis.

https://www.claas-group.com/press-corporate-communications/press-releases/lexion-8000-and-7000--new-high-performance-combine-harvesters-with-up-to-790-hp/2028102

I took that tire size from official brochure, IDK if it was right move. and i dont know which is the "default" one. 

but thank you for the correction. appreciate it  @1gor

800x300.png

Edited by mktechniccreations

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@mktechniccreations default one is based on harvesters power; usually first column indicate default (and recommend by manufacturer) tire option(s). It is no problem to help.

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15 hours ago, Jeroen Ottens said:

Drive needs to have it’s own XL motor as this will be a heavy model. I might couple a fake engine and the fan in the top to this motor as well.

The model will be very heavy. My Lexion weighs almost 5kg. I had to put the Unimog tires into the Power Puller tires because they were falling off the rims. Agri tires are much harder and this shouldn't be a problem.

15 hours ago, Jeroen Ottens said:

Steering and lifting the front idler will be done with an L motor.

do you mean header lifting? If so, the L motor will be too weak. Check available header widths. Your model uses the widest headers which will be very heavy.

15 hours ago, Jeroen Ottens said:

should I make this an RC pneumatic combo with six RC pneumatic functions or should I keep everything electrical?

I wanted to use the pneumatic functions but gave it up. I prefer LA. They are much more precise and take up less space.

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1 hour ago, eric trax said:

do you mean header lifting? If so, the L motor will be too weak. Check available header widths. Your model uses the widest headers which will be very heavy.

I mean lifting the front wheels of the Terratrac when the model steers. But I agree that lifting the header will require quite some force.

1 hour ago, eric trax said:

I wanted to use the pneumatic functions but gave it up. I prefer LA. They are much more precise and take up less space.

For me the disadvantage of pneumatics are indeed the spacerequirements of all the tubing, the fact that tubes always go perpendicular from the actuators and the limited selection of actuators (although that has improved a bit with the extra long cilinders)

On the positive side, routing the ‘signals’ from the gearbox to the actuators is very flexible with the tubing. And it is more authentic as @allanp would argue :wink:.

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