Flybum Posted June 2 Posted June 2 (edited) From the outside, the mechanics of this backhoe are not easy to understand, so I prepared a transparent rendering that shows the full internal layout. Each of the six motors has its own color‑coded transmission chain, making it easier to follow how the power is routed inside the model. If you’re interested, this video shows the complete internal structure and how all 10 functions correspond to the six motors: Link to my previous post: Edited June 2 by Flybum update Quote
yqc Posted June 2 Posted June 2 Very impressive! From this statement on Rebrickable: Quote - 6 motors driving 10 independent functions, organized into Front Mode and Rear Mode Do I understand it correct, that there are five motors which have exactly one function in the back and one in the front and the sixth changes which function to use for all at once? It might be just me, but I didn't really notice that in the video. Yeah, the amount of different "axle lines" (is there a word for it) in such a tight space is really done amazingly. Just how much you need to curve these lines in weird ways shows, how much effort this is, to get everything into such a constrained space. And I already have 80.1% of the parts, so I've added it to my Build List and will hopefully find the time to build it. Quote
Flybum Posted June 2 Author Posted June 2 51 minutes ago, yqc said: Very impressive! From this statement on Rebrickable: Do I understand it correct, that there are five motors which have exactly one function in the back and one in the front and the sixth changes which function to use for all at once? It might be just me, but I didn't really notice that in the video. Yeah, the amount of different "axle lines" (is there a word for it) in such a tight space is really done amazingly. Just how much you need to curve these lines in weird ways shows, how much effort this is, to get everything into such a constrained space. And I already have 80.1% of the parts, so I've added it to my Build List and will hopefully find the time to build it. Almost! The general idea is right, but the internal setup works a bit differently. There are 6 motors in total: 3 large motors are the “main” ones. In Front Mode they drive the 3 front functions (boom lift, boom tilt, drive). In Rear Mode the same 3 motors control the 3 rear functions (boom lift, dipper lift, bucket tilt). So each main motor has one front function and one rear function, selected by the gearbox. Then there are 3 medium motors: 1 medium motor is dedicated to switching the mode. It performs a three-step automatic sequence using two clutch gears: – it switches the motor selectors – it rotates the driver’s seat – it raises or lowers the stabilizers. 1 medium motor is dedicated to steering. 1 medium motor is dedicated to rotating the rear boom. You can see the transmission chain for the mode‑switching sequence in the video I linked above at points 5 and 6. And if you want to see how this translates into actual controller commands, here’s a short video that shows it in action. Black levers=main functions. Blue lever: forward: front mode/backward: rear mode. Yellow levers: dedicated functions. https://bricksafe.com/files/Flybum/full-rc-backhoe-loader/Test%20Commands.mp4 Quote
Jundis Posted June 3 Posted June 3 What a dense built! My oh my, how did you put all those motors and mechanics in? Really impressive, and seems to work so smothly :-) Did you try with the 81 tractor tires on the front just for the looks? Quote
Flybum Posted June 3 Author Posted June 3 (edited) Thanks! I tested several front‑wheel options, but these matched the real vehicle best. And, since the front and rear wheels have different diameters, you need a vertical offset to keep the chassis perfectly level. With this combination, the required offset is exactly 1.5 studs, so achieving it with a half‑stud addition is straightforward. The front axle also has to pivot longitudinally, so keeping the geometry simple really helps. Edited June 3 by Flybum Quote
Jurgen Krooshoop Posted June 3 Posted June 3 Amazing model and technically very impressive. Well done, I like it a lot. Quote
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