DrJB

Question is self explanatory ... Which set, made you realize Technic has undergone a radical transformation, and it was time for you to come back? For me, it was a combination Williams F1 Racer and Mindstorms RCX 2.0. I was in Hanover, Germany for a summer assignment back in 2003, visited one of their stores ... and there stood this blue and white F1 racer ... Did not recall Lego could build such large sets from 1x16 bricks (or 1x15 liftarms). The new curved panels and flex axles looked almost 'organic'. Next to the Williams, was a bundle of Mindstorms RCX 2.0 + Vision Command. It was rather expensive back then, but when I got back home to the US that fall, I ordered the RCX from Shop@Home. Somehow the F1 Racer was no longer available.

If I am to 'classify' the various forum members in this forum, I would bin us in the following groups: 1. Those who come here to replicate mechanisms and contraptions that we learned at school (e.g. 4-bar linkage, self-balancing EV3 robot, ...) 2. Those who 'believe' Lego is a 'replica' of real life and use such medium to learn about everything mechanical out there 3. Those who are fully aware of Lego's limitations and realize it is a gross 'simplification of real mechanisms. 4. Artists and Scale Modelers .... etc Looking at all the contraptions available to us, some of those mechanisms are simplified versions of real life, while others are more complicated versions. Here are two examples: 5. Suspension - None of the angles/geometry are reproduced (camber/caster/...) - Lego is definitely an over-simplification of real suspensions 6. Multi-Speed gearbox (e.g. 8448 and 8466) - I believe that, from the kinematics, those are MORE complicated than real life. Somehow, the Lego designers had to give us a working gearbox given the limited available parts. Scanning through the collection of Official Technic Sets out there, which mechanisms are: 7. Simplified Version of Real Life 8. More complicated than real life 9. Just exactly like real life

Points 7/8/9 (in Bold) I've heard on many occasions people who try Technic for the first time make comments such as: 'Like the real thing' .... No, few mechanisms in Technic are like the real thing. Some are more complicated, others much simplified. I'm talking here primarily about the kinematics.

We all come to this forum from many backgrounds and with various interests. Many of us are engineers (mechanical/electrical/...) and many others either aspire to be or are simply curious at the intricate workings of all the machinery around us. While on a plane back home from the holidays few days ago, I was 'reflecting' on the topics/aspects I learned in this forum that I possibly would never have encountered in my life. Yes, I'm a Mechanical Engineer and know a lot about gears, mechanisms, and machine design, but some topics on here I never 'knew' existed. Here are few examples: 1. How helicopters fly, by maneuvering the direction of the Lift Vector via Collective/Cyclic controls 2. Ability to generate almost any gear ratio by using clever combinations of gears with 8/12/16/20/24/28/32/... number of teeth - Search the Lego Antikythera topic 3. Adder/Subtractor with differentials What can you add? What have you learned in this forum that you would otherwise never have thought of nor encountered?

I like this one, for a more 'stable' suspension. Also, how about parts to experiment with multi-link suspensions? ... i.e., those having Negative "scrub radius", as in some Audi vehicles.

Not to beat this to death, but I'm fully aware of the various connectors that enable one to mix full and half-width beams. Some are displayed below: All these connectors are there to connect primarily full-width with half-width parts. What I understood from the discussion thus far is that it seems some EB members, pursuing smaller and more compact cars/builds, are seeking ways to use 'primarily' half-beams ... Hence my comment about needing more half-beam connectors and structural integrity of such thin beams. Let's put this to rest now :)

+1 for fender pieces ... there are way too many of them, and to me they are of very limited usage. As to for axles, I was sorting mine yesterday, separating into 3 colors (gray/bluishgray/black) the 3/5/7M axles ... and I discovered I had two 8M in gray. I never recalled where they came from, but then found out they belong to R2D2 ...

I'm fully aware of such part, though thanks. My point was for a planetary hub that we can customize and see the inner workings by e.g., changing the number of teeth of the sun/planets, or even build an automatic transmission with multiple-stage planetaries. The example you're showing is closed and very few people understand the inner workings. Can you imagine if we had a planetary hub (spider/carrier + ring) and what we could do with that? Very nice, though the direction of printing (stacking of PLA layers) will likely lead to weak components in torsion. It might be worthwhile to print in a perpendicular direction, though the surface finish might be less adequate.

You're missing my point, and my experience is a bit different than yours. Not to lecture, but I have seen Lego Technic 'evolve' over the past many years and some things are either not doable, or structurally weak (I'm wearing my engineer's hat here). Here is an example to illustrate my point: Imagine you want to stack 1 regular beam between 2 half-beams, one on each side. There is no 2L connector that will hold this assembly together as all 2L connectors have a ridge in the middle. You also need to consider that when Lego Technic started (see pics below), it was all about replicating mechanical functions (The first engine cylinders were square). Nowadays everyone wants to motorize their MOC and turn it into an RC vehicle. Not all parts can sustain such abuse. You might disagree, and that is fine, but my point remains: half beams are very restrictive in their use, simply because the 'resolution' for most other parts is full-width. In the end though, these are YOUR parts, and you're free to do with them as YOU please. *cheers*

The one thing we're missing here is that most parts (Connectors/Gears/...) are 1M/L thick. It's nice to have all of these 1/2 thick parts but their use will be most likely very limited (again, due to the majority of the available connectors). Plus, once you go half-thick in one direction, you loose the 'uniform' spatial resolution of 1L in any of the 3 directions. Such 'resolution' was a big step going from system/studs to technic beams ... but challenging it with half-whatever in any directions is poised to create many more issues and problematic builds. IN all the connections and parts they have developed, TLG has been very religious about respecting the 1M/L resolution/grid. Even the oddly looking Bionicle parts obey such rule. I saw a paper recently about the working of the CCS connections (articulated science) and there is some 'science' behind it, not just "I wish" I had such feature. Again, maybe I'm talking more like an engineer and less like a Lego enthusiast. Another thought: How about planetary hubs? The only option today is with the PowerMiner parts shown below, but those are not very usable in any realistic/compact Technic build (besides PowerMiners).

I agree that such parts offer 'infinite' possibilities for vertex angle. I've used them a while back but back then the friction 1L pin was not available. Still, for chemical molecules, it is good to have FIXED angles. The way to differentiate the angles would be to simply make those parts in some 'limited' colors as TLG has done many times for axle lengths and small parts that are easy to confuse. Imagine all Chemistry classrooms adopting lego parts in their education ... waow!!! On a different note, I'd like to see axle connectors, or axles, whose cross-section is rotated by 45 degrees. This would enable us to build holonomic wheels and even more chemical molecules. Something like the one below, but where both ends are rotated by 45 degrees relative to one another. Yes I might be able to cut/glue few of those ... but that would not be too clean/efficient. Also, and as an option for the above, we could make the two axle ends 'indexable' by using a smaller and more compact version of this connector.

Imagine these angle connectors but with angles more than just multiples of 22.5 Having those would open the door to chemical models and more solids such as in the thread below.

Sorry ... I missed your vehicle size/scale limitation. In fact I'm rebuilding my 8466 now, it's been in storage for years ... gotta love those silver green panels, and the 4L bar used as light ... way ahead of actual vehicles.

Look up 8466. It might have exactly what you're after.

Slightly better if you copy/paste the image directly (right click then copy/paste) :)

Thank you for the travel back in time. I was at MIT back then, doing a PhD in Mechanical Engineering. The Electrical Engineers were developing robots based on some controllers and Lego parts (Course 6.270) during the month of January (Independent Activities Period) whereas their Mechanical engineers counterparts were also developing 'fighting' robots from actual hardware (no Lego), Course 2.70 was a full-term Design course. In fact the EE course number was even adapted from that in Mechanical Engineering. The enrollment in 6.270 was via a lottery system as many students wanted to take the course than were spots available. In fact the RCX bricks were developed in the 90's, when the 6.270 Staff decided to do away with the Motorola controllers and switch to something more 'usable'. That is also when many schools across the US and the world (FLL) decided to develop their own Robotics courses based on mindstorms. Incidentally, I visited Boston/MIT few days ago over the holidays ... so much has changed in 30 years (Campus is no longer 'open' and requires key cards to navigate through), Boston Skyline has changed, parking is an even bigger pain .... but still, that place (in my mind at least) shines like a bright beacon across Cambridge/Boston. I was lucky as some people let me in the library and other places ... all I had to say was that I'm an alumni ... so many memories.

About 10 years ago I bought 2x 13 Gallon totes with lots of parts/sets for only $20. Those included many Bionicle/Agents/PowerMiners/ExoForce Sets ... Now cleaning/sorting those sets. There is at least $2000 worth, especially the Bionicle, and a rare glow-in-the dark octopus from the Agents theme, worth about $100.00

Are you familiar with this this part?

Well ... there is a way to answer whether it's dust or stresses. Plus, which stresses are we talking about? The stresses due to assembly or those due to the weight of the vehicle and some parts being exercised along many directions (torsion/bending/etc). One way to answer the latter is to send the assembled model to the space-station (zero gravity), let it sit/relax there for few months (astronauts are allowed to enjoy Lego as well), bring it back to earth, and see what happens. Incidentally, one can build a 'twin' and keep it on earth for reference/control. They did send a Raspberry PI to the ISS, why not a Sian? Seriously ... we're dealing here with plastic (ABS or else), and plastic does 'creep' with time. I 'believe' it is a combination of dust/humidity and of course creep/relaxation.... My 0.02, though same answer as everyone else, nothing new.

I happen to have both ... :) ... but I'm with you 100%, most likely it's a cost consideration. You could also ask how come we never see any 4-wheel steering (except for 8880), though I'm sure they have their reasons. AFOLs are NOT the main target audience for many of those sets.

The camera's performance is much better in a bright room. Otherwise it's just grainy. I used it with the RCX 2.0 about 14 years ago, and it performed ok, including motion detection etc. My son used it to sound an alarm whenever anyone stepped into his room. So, it is pretty capable, but do not expect a GoPro 11 performance and image quality.

It all depends on what you mean by 'will it work?' I understand that in Germany and during Christmas, many households have a 'fan' device that spins due to convective heated air from a candle, and that is a beautiful tradition. Now, whether the MOC will survive the heat ... that's another question. Time for experimentation? I do not ever recall reading anywhere what the 'usable/safe' temperature for Lego bricks is, but that info sure would be a good starting point. Oh, and by the way, ... nice contraption that you've made. PS. I never truly understood emojis in EB, as they are different from the widely-used others ... but just now I realized those are actually minifg faces ...

Most contraptions out there focus primarily on the kinematics, styling, and number of functions, whether motorized or not. Except for few rare examples, very little is done to address the dynamics of things we build,. Hence, the raison d'être of this thread. For those curious about what I'm after, here is an example: In a world where most universities are merging their dynamics and controls courses, isn't it time we explore what can be done with closed loop control, whether classical (PID type) or Full-State (such as the inverted pendulum above). At the very least, some sort of contraption that would demonstrate the effects of Proportional/Derivative/Integral gains, and how they affect the dynamics of such contraption. Yes there are few examples on youtube, but many are very 'technical', use Matlab, and quickly get lost in the details.

I do not like the colors ... oh wait, I work for the competition (red machines) Nonetheless, beautifully done :)

I was building a contraption (Platonic Solids) using a combination of the parts below I had gotten a large number of the last one in 'pearl gold'. Such color however is made of a different/softer plastic than other typical colors, and this results in the mating parts having very little clutching power. Of course TLG is very well aware of this, and they simply cannot design different molds for different materials. The point here is, when you're planning your next project, choose your colors 'wisely'. In any event, what I found is: 1. Highest clutching power - trans colors 2. Typical clutching power - typical solid colors 3. Lowest clutching power - pearl gold and most parts used in the Bionicle sets Any member on here with expertise in plastics cares to comment?