Ludo Visser

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About Ludo Visser

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    Set 42054

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    The Netherlands
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  1. Ludo Visser

    Generic Contest Discussion

    GXC maybe, for those who don’t have those balls?
  2. Interesting video, but as you've found out, differentials don't work like that when you drive the outer gear. Without considering the external torques (e.g. you holding the output axle), the problem is ill-defined. Basically, the differential is a three-"port" system, where every "port" is a pair of rotational velocity and torque: ______| (w1, T1) | __ | (w2, T2) ---------|-| |-|--------- |______| | (w0, T0) (excuse me the poor ASCII drawing). Power = rotational velocity x torque, or P = wT, and since a differential is a passive component, the sum of all three products must be zero, i.e. all power that goes in must go out somehow: 0 = P0 + P1 + P2 = w0 x T0 + w1 x T1 + w2 x T2 If you choose to drive w1 and w2, then we know that w0 will be the average of the two. This is a consequence of the mechanics: the third internal gear is fixed to the housing and thus constraint. This means that w0 is an output variable and w1 and w2 are input variables: w0 = (w1 + w2)/2 In matrix form, you'd have [w1] w0 = [ 0.5 0.5 ][ ] [w2] If you have studied linear algebra, you know this relation cannot be inverted: there's infinitely many solutions for w1 and w2 that satisfy this equation. That's exactly what you found out when you drew the two lines in your graph and noted that there's not a unique value for x or y. The complement of the above equation is [T1] [0.5] [ ] = [ ] T0 [T2] [0.5] Which should be familiar also: both shafts of the differential get halve the torque in nominal conditions. To properly analyse your mechanism you need to consider the torques that act on the input and output as well, then the problem becomes well-defined and you can solve the equations uniquely. @ukbajadave showed how playing around with internal torques can give you some interesting results. (I'm still trying to find time to do the math on that)
  3. Ludo Visser

    [MOC] [WIP] Forestry Tractor

    I was referring to the tractor’s wheels, they’re Fishertechnik also?
  4. Ludo Visser

    [MOC] [WIP] Forestry Tractor

    Oh, I want to build that...! (...once I get my building desk back from the home office setup...). What wheels are that exactly? The same as in your other tractor?
  5. Ludo Visser

    [WIP] Space Shuttle

    I think that’s an improvement! Do you think you can close the gap at the bottom a bit? White is terrible in that respect: any gap is immediately obvious.
  6. Ludo Visser

    Using a differential to design gear ratios

    This is a nice explanation! The principle is simple, but a good, clear demonstration is always helpful.
  7. Ludo Visser

    Liebherr HS 8040

    Wow, I really like this! Works smoothly and you put in a lot of functions in such a (relatively) small structure. Well done
  8. Ludo Visser

    [WIP] Space Shuttle

    Oh, 8480 was great, loved that set! I always say to myself I should rebuild it some day, but never get to it... Looking forward to where this is going (payload...?) I have to agree with @Erik Leppen and @MangaNOID though. While the real orbiter was a bit flattened on the top also, it wasn't actually flat on the top. Closer to a cylindrical shape: In 8480 it worked great with the 6x4 angled beams with the single 16M studded beam of the robotic arm squeezed in the middle. I hope you can find a better solution also...!
  9. Ludo Visser

    [TC17] Rebel Tow Truck

    That freaked me out too...! Otherwise great video and photo's. And an awesome build of course
  10. Ludo Visser

    [TC17] Rebel Tow Truck

    Keep the chassis. I think it's great and a wonderful nod to the Rebel Wrecker. Awesome build!
  11. Antartica is a desert... Plenty of snow.
  12. Ludo Visser

    Tips for an 8480 rebuild?

    That was a great set. I have a ton of "old" LEGO that is never used, but I keep it just in case some day I want to rebuild 8480, 8868 or 8880... I doubt it'll ever happen though. If I understand you correctly, the set is currently assembled and you intend do disassemble it, clean the parts, and then build it up again. Some parts have likely become brittle and might break easily, so my main recommendation is to be very very careful during the disassembly. In my memory, especially the old-style bushes (full and half) and the axle-pin connectors are easy to crack (but you also might have replacements for them if you own more sets from that era): The clips holding the micro motor are also all broken on my set, and I have a number of the wheel hubs broken, but I don't know if they came from this set or from my first ever set. The cables might be fragile, but if they haven't seen any use for all those years, there's a chance they're not frayed yet. The cables had different types of insulation over the years, some holding up better than others. I don't recall which type was used on 8480,
  13. Ludo Visser

    Liebherr LTM 1070-4.2

    That is absolutely stunningly beautiful! It seems to work super smoothly as well. I can't believe it's only 2700 pieces... Awesome job, well done!
  14. Ludo Visser

    [MOC] Iveco Skip Loader

    Your recent John Deere catapulted itself to very near the top of my list. The Volvo refuse truck is also on it. In general I really like the scale of your MOCs and I intend to learn from them by building them. But I'm possibly the slowest builder ever, so don't hold your breath First is finishing my own MOC...!
  15. Ludo Visser

    [MOC] Iveco Skip Loader

    Very nice! I like those smaller, playable MOCs a lot. Still have some of yours in my to-build list...