Technic Complexity vs. 'Limited' Parts Selection

[DrJB]

Yes, this another 'discussion' topic and there is no right/wrong answer.

I've been pondering at the various designs (both Lego originals and MOCs) aimed at mimicking real-life mechanisms. While in real life you can build/design anything, with Lego, we're limited to the type/number/geometry of parts at hand. The most obvious example is the transmission (gearbox) in the 8448/8466 super cars. In real life, a 5+R gearbox needs only 12/13 gears whereas those in 8448/8466 use more gears than that.

What mechanisms can you think of that are MORE complex (when built in Lego) as compared to their real-life counter-parts?

Other extreme examples that come to mind are the various mechanical clocks and the antikythera. The Lego re-enditions use more gears than the original designs, simply because of the limited number of available gear teeth.

Edited December 2, 2014 by DrJB

[nerdsforprez]

This is one reason why I am not a LEGO purist. I try to always use genuine LEGO parts. However, sometimes it is fun to modify sets or parts to create something better. It is the exact epiphany of creating! I am not just a LEGO builder.... but a builder period! LEGO seems to be the best avenue right now to express this desire... but when something better comes along, I do not restrict myself from using it.

With that I say.... Go Efferman!

[__________________________]

Yes, this another 'discussion' topic and there is no right/wrong answer.

I've been pondering at the various designs (both Lego originals and MOCs) aimed at mimicking real-life mechanisms. While in real life you can build/design anything, with Lego, we're limited to the type/number/geometry of parts at hand. The most obvious example is the transmission (gearbox) in the 8448/8466 super cars. In real life, a 5+R gearbox needs only 12/13 gears whereas those in 8448/8466 use more gears than that.

What mechanisms can you think of that are MORE complex (when built in Lego) as compared to their real-life counter-parts?

Other extreme examples that come to mind are the various mechanical clocks and the antikythera. The Lego re-enditions use more gears than the original designs, simply because of the limited number of available gear teeth.

However, Lego parts are (mostly) easier to find and buy than the IRLV.

[Erik Leppen]

What mechanisms can you think of that are MORE complex (when built in Lego) as compared to their real-life counter-parts?

While it doesn't count as a mechanism, many shapes, mainly curved shapes/surfaces, are very hard to recreate in Lego because of the rectangular grid that Lego works best in. One notable example is the hull construction of a car. In real cars the columns that form the windscreen help give a car a lot of strength. In Lego, all the strength has to come from the chassis alone. Building a strong hull was one of the design principles behind my hypercar model.

That brings to the second example: building a strong rigid frame is much harder in Lego than in real life. In reality it's a few beams. In Lego it's an intricate network of interlocking beams with the right connections in the right place, so that it's both strong and doesn't take up too much space.

[Captainowie]

What mechanisms can you think of that are MORE complex (when built in Lego) as compared to their real-life counter-parts?

All of them?

Reason I say this is that if there is any LEGO mechanism that is less complex than its real-life counterpart, then almost by definition the LEGO version is not as capable, or not as strong, or not as something else.

[DrJB]

All of them?

Reason I say this is that if there is any LEGO mechanism that is less complex than its real-life counterpart, then almost by definition the LEGO version is not as capable, or not as strong, or not as something else.

I am not sure I understand your point nor agree. I am looking for lego mechanisms that are MORE complex than their real life versions. Typically, most lego 'adaptations' are LESS than the original, as in examples below:

Steering mechanism: lego uses pinion+rack, real life uses bearing-screw with recirculating balls.

6-Cyl engine: Lego crank shaft segments are shifted 180 degrees. Real life 120.

Suspension: different size lower/upper control arms. Lego are same size.

Tire/suspension angles: real-life uses (camber, caster, toe-in, ...), Lego suspensions are more 'simplistic'

Differential: real life uses hypoid gears, Lego straight teeth

...

Edited December 5, 2014 by DrJB

[Lipko]

I am not sure I understand your point nor agree. I am looking for lego mechanisms that are MORE complex than their real life versions. Typically, most lego 'adaptations' are LESS than the original, as in examples below:

Steering mechanism: lego uses pinion+rack, real life uses bearing-screw with recirculating balls.

6-Cyl engine: Lego crank shaft segments are shifted 180 degrees. Real life 120.

Suspension: different size lower/upper control arms. Lego are same size.

Tire/suspension angles: real,life uses (camber, caster, toe-in, ...), Lego suspensions are more 'simplistic'

Differential: real life uses hypoid gears, Lego straight teeth

...

I don't understand your point either. You seem to be picking random details to fit your prejudging of what's more complex in Lego and what's less complex.

By your logic I quoted, Lego transmissions are much more simplistic than real ones. Since there's much more to a gearbox than the number of gears and driving rings. Syncronizing-rings, healical gears instead of straight gears, more sophisticated gear-swithing mechanisms (for example switching reverse), etc.

Lego suspension can be as complex as you want it to be. And mimicing all those angles you mentioned, usually a more complex Lego solution is needed than a real suspension.

[DrJB]

Fair enough, let's try again (and I'm not pre-judging). Let's stay on the topic of transmissions. Granted, new ones are more complex, but if we focus on the actual gear reductions, you cannot mimic that same architecture with lego gears. And thus, lego transmissions (8448/8466) use MORE gears to mimic the ratios of real life transmissions. Typically, lego mechanisms are SIMPLER than those in real life (as you rightly pointed). In the gears for a transmission, it's exactly the OPPOSITE. I am looking for examples where a lego implementation is MORE complex (than real life) simply because of the limitations of lego parts. 'all of them' in the above post is simply not true. Makes sense now?

Edited December 5, 2014 by DrJB

[weavil]

Any front wheel drive car has a Rack and Pinion steering that works just like the Lego parts.

I just thought, could the Braiding Machine work as an example?

[Lipko]

Still not getting it etirely, but I think the best and most obvious example is the use of linear actuators in Lego instead of hydraulics in most real machines.

Edited December 5, 2014 by Lipko

[DrJB]

Still not getting it etirely, but I think the best and most obvious example is the use of linear actuators in Lego instead of hydraulics in most real machines.

We're getting there, the use of LAs is a perfect example. It uses 'non-conventional' technology to mimic hydraulic pistons.

[Captainowie]

I am not sure I understand your point

Ok, let me try again. I think this came out in Lipko's post, but I want to make it more explicit. You said:

Typically, lego mechanisms are SIMPLER than those in real life

LEGO mechanisms are generally simpler than those in real life because they generally do simpler things. Staying with transmissions for the moment, consider what was perhaps the first LEGO transmission (http://technicopedia.com/853.html) - just two speeds, certainly simpler than a 'modern' (even in the 70's) 4+R transmission with synchromesh and a whole bunch of other stuff, but there's a lot that the modern transmission can do that the LEGO version can't, because of that simplicity. If you want to replicate all the functions of the modern transmission, then you need to use more gears, making the LEGO version more complex than the real-world version.

On the other hand, let's look at something you've identified as simpler in LEGO than in real life - steering. Even without the rack-and-pinion vs bearing-screw difference, a real-life steering system has the pivot point of the tyre inside the footprint of the tyre itself, and turns the inside wheel more than the outside wheel, and presumably a whole bunch of other stuff as well. It's certainly possible to replicate this behaviour with LEGO but, like with the transmission, it bumps up the complexity of the build until it becomes greater than that of the real-life version.

Even something as straightforward as a simple gear reduction is often a lot more complex in LEGO. Want a 6:1 gear reduction? In real life you just need two gears. In LEGO your best bet would probably be a two stage system consisting of 2:1 and 3:1 reductions. What about a 12:7 reduction? There exist 14t gears and 24t gears, but the axles need to be spaced 2.375 studs apart, so again the complexity grows.

This is why I stand by my answer of "All of them". Anything that is simpler in LEGO than in real life is only simpler because it is representing a subset of the capabilities (albeit including the defining feature) of whatever is being built.

Is that clearer?

Owen.

[Kumbbl]

Building a strong hull was one of the design principles behind my hypercar model.

just seen this Hypercar - way cool - i think i will build it - intersting design and construction :thumbup:

[Boxerlego]

Differential: real life uses hypoid gears, Lego straight teeth

Hypoid differential gearing has nothing to do with the style of gear teeth mesh. Hypoid just describes the position of the drive shaft gear to the differential ring gear. The lego differential can use the hypoid gear offset and it is strong in one direction but slips in the other. It just happen to be that spiral bevel gears are the preferred style on the real component for several specific reasons, the one I was taught in school is that to increase surface area on the gear teeth so that more torque can be transmitted on the gear with out breaking. The helical style of gear mesh is to complex for Lego to endure because unlike spur type gears, helical gear create a separation force that can create more friction wear on the lego parts if not prevent and and is regarded as the main disadvantage for such type of gears in the wiki article.

Edited December 7, 2014 by Boxerlego

[weavil]

A locking and limited slip diff can be more work to in Lego.

[DrJB]

A locking and limited slip diff can be more work to in Lego.

Thank you.

When I started this thread, I had in mind the radical differences between a Lego transmission (6 shafts and 6 couplers) and one that you find in classical (non-automatic) cars with only 3 shafts (input, output, +1 for REV), and the 6 couplers (syncros) aligned one next to the other. Of all transmissions I've seen (and I am a mechanical engineer) I have never encountered one (in real life) whose layout resembles that in 8448/8466. Now, it seems many on here jump to lecturing and assuming the OP got no clue what he's talking about (fine). But for the sake of civility, let us try and UNDERSTAND what the OP had in mind, before assuming he missed the boat and tell him he can implement hypoid gears with Lego (I'd really love to see that!) ...

Peace .. and happy building, this is just a Hobby ... and if one can't be 'relax' about it, they should try something else.

Edited December 8, 2014 by DrJB

[Captainowie]

tell him he can implement <whatever> with Lego

But of course you can! If you can imagine it, you can build it!

Regarding hypoid gears in particular, if what Boxerlego says is correct and the "hypoid" bit just means that the axles are not in the same plane, then that's easy to do with a crown gear or the oldest style differential. If you insist on having the helical teeth that's fine - it just means that the resulting gears will be more ... complex (and too large and too weak to be of any practical use whatsoever). I'm imagining something using a bunch of ribbed hoses held in the right shape.

Owen.

[Boxerlego]

Spiral bevel gears are real complex for lego to implement not only do they create a separation force that will pose as problem but there would also be need for two different differential designs due to the helical design.

As for a Hypoid and Amboid style of differential gearing is possible when you do it with a offset of half a node. But when you offset the drive gear by one node up or down you will have an offset that is to much for the gear teeth to properly mesh together and work as desired and is the one I'm referring to in the my previous post above. The differential setup with half a stud offset I just made this morning and never tested for clarity

Edited December 8, 2014 by Boxerlego

[DrJB]

But of course you can! If you can imagine it, you can build it!

Regarding hypoid gears in particular, if what Boxerlego says is correct and the "hypoid" bit just means that the axles are not in the same plane, then that's easy to do with a crown gear or the oldest style differential. If you insist on having the helical teeth that's fine - it just means that the resulting gears will be more ... complex (and too large and too weak to be of any practical use whatsoever). I'm imagining something using a bunch of ribbed hoses held in the right shape.

Owen.

Aye aye Captain

Very nicely done. I like especially how you did the 1/2 offset. While I reckon my reaction to the hypoid comment may not have been fair, I must admit this thread has generated more ideas/discussion than I had intended. And that is all good, as I learned something new today ... that some axes offset (as in hypoid gears) is certanly realizable.

Cheers.

[Boxerlego]

Thanks DrJB! Cheers, glad I can help make things clear. To keep the discussion going I want to this about this quote where you brought up another good point.

6-Cyl engine: Lego crank shaft segments are shifted 180 degrees. Real life 120.

Typically yes the axles are restricted those 90 degree increments (90, 180, 270, 360) but there is a way to shift the axle alignment to get the real life 120 degree by using this part and three 1x2 thin liftarm to basically make an axle connector with that desired offset. I did this for my

where not only is the crank throws are 120° apart the V-angle on this engine is 60° and this setup is consider to be the most efficient style of the V6 engine. I consider my V6 my most complex engine in terms of what was accomplished with the cylinder bank angle and crankshaft. Usually if you building in the standard lego paradigm the V-angle on lego engines will be 90° but because the V6 was built was on the right scale it was possible to make it happen. Same thing applied to the V8 engine. The V8 engine when built bigger then its smaller Technic design can incorporate both crossplane and flatplane style crankshafts while little Technic one can only incorporate the flatplane. Just like engines, Transmission or gears in general will share that same common problem.

90°

120°

[DrJB]

Now this is getting serious ... and I like how this discussion is going, and as well how you offset the two half-shafts by 30 degrees. All I need is try this at home (after work) ...

Also, if I recall, there was another way to move the pistons of an engine, not just the starndard lego cranks. I believe this was in one of the recent motor-bikes.

[Boxerlego]

Exactly DrJB, the axle connector here can make any axle offset in multiples of 30 degrees. I made a Axle angle diagram displaying all the possible angles.

Going back to my 6 cylinder engine I was able to achieve the 60 degree V-block angle by using this pattern. It also can achieve some unique gear distance but because of the nature of the design its not a exactly a solid frame construction when dealing with gear meshes. Considering both Technic Complexity and "Limited" parts selection Lego can certainly achieve way more stuff because of size. My Brick built V6 engine was able to use this Technic pattern as a frame because the size of my Brick engine is naturally able to align with it Technic construction. The bigger size open ups the parts to use versus when you building on a smaller level you become restricted to what you can build exactly. I always compare my Brick Engines to the Grey Technic Engines because that is exactly what I used as a base reference for their design construction. The way the Grey Technic engine was designed for the LEGO system it self became a system of its own because these vacuum engines would never really run that efficiently with out the grey engine crank shaft piece that connects with the pistons rods. The Axle part above in the diagram basically allows the main Axle structure to connected the optimally close together, buts its not of optimal design construction in regards to space; However, on the other hand its the most optimal thing to use in order to achieve any of the possible axle angel variations with the design.

Enough about Engines for now. Lets talk about Transmissions. I recently saw a video by Crowkillers about the new changes for Lego transmissions.

This is exactly on base with your topic when you consider the Technic complexity for building transmission before this new driving ring. Now there is a mechanism for you that is not more complex when built in Lego but I would say less complex for the simplicity at which Lego can achieve it.

Yes, this another 'discussion' topic and there is no right/wrong answer.

I've been pondering at the various designs (both Lego originals and MOCs) aimed at mimicking real-life mechanisms. While in real life you can build/design anything, with Lego, we're limited to the type/number/geometry of parts at hand. The most obvious example is the transmission (gearbox) in the 8448/8466 super cars. In real life, a 5+R gearbox needs only 12/13 gears whereas those in 8448/8466 use more gears than that.

What mechanisms can you think of that are MORE complex (when built in Lego) as compared to their real-life counter-parts?

[bonox]

at its most basic, a 'real life' item can make use of any device required for the job - an arbitrary gear ratio, friction materials (the limited slip diff example), custom housings, offsets, materials etc to get the job done.

ANY product made using a limited selection of COTS parts (which is fundamentally what LEGO is) may be able to manufacture a range of outputs beyond the available inputs; it will naturally take many more parts to manufacture a 12.66:1 gear ratio out of stock 8/12/16 etc cogs than a custom single pair set.

Same argument goes for configuration - anything not built on square lattice or multiples of available angles through type 1-6 connectors, axle/pin connectors etc will naturally be more complicated if you have to built it using more than one custom part.

I'm not sure about the hydraulics argument either - fundamentally a motor directly coupled to a LA is very simple and probably less so than the equivalent real life unit of a motor, hydraulic pump, valving (distribution and check), filters, couplers, piping and cylinders. The real ones will also use bearings instead of letting fixed parts slide inside other fixed parts. Same argument with seals.

I'll give you a super simple example - make a G-clamp out of two parts in lego - ie the real one is essentially a shaped frame and a screw. There's no way you can beat that in a system of straight or straight plus angle arrangement of parts that doesn't include any screw mechanisms. That's not to say it can't be manufactured, like a multi-part frame and LA for example, but it will always be more than two parts custom made for the job.

different one - a sequential drum style gearbox shift mechanism.

An interesting detour on this conversation would be "using a limited array of parts, how would you create the same result". The answers can look very different to the 'original' but work nonetheless.

This question after all is why we now have a palette of hundreds of parts when Expert Builder started out with, what, six? Gear, axle, rack, pulley, bearing/plummer block (the brick with holes) and the bush.