Massive 12 axle crane; comments and concerns

[aminnich]

Hey guys, this is not a WIP topic, not yet

I wanted to see if anyone had any thoughts on this crane concept. I understand this build is going to be freakin crazy big, but thats the point But anyway, i am wondering if anyone has build ideas.

As of right now i just have a bunch of sketches of what i want to do. Here is what im thinking;

5 front steering, 5 rear steer and 2 middle straight. Those 2 middle will be powered along with 4 steering axles.

X outriggers over the rear steering axles, possibly adding another X type outrigger in the front of the crane

I have to figure out how i can incorporate multiple steering modes as well.

Any thoughts and concerns would be awesome, nothing talking me out of this :grin:

[cheeze]

Heres something for your inspiration https://www.flickr.com/photos/94115249@N02/

Are you going for full function on it?

[aminnich]

Full RC, yes

As for the inspiration, yes it will be that huge. Im hoping i can keep the boom on my crane.

[cheeze]

Just have to work on the pivot, i dont know how Huibs if fixed, im a crawler crane man myself, and i have the boom only held with a 3l axle with stop

[aminnich]

Pivot as in turn table, or lifting the boom pivot?

[allanp]

All was well until you mentioned multiple steering modes, which is a head ache to achieve in Lego.

I real life the many steering modes require a complex computer controlled hydraulic system. The computer takes into account all the proper Ackerman geometry which is going to be the tricky part as each steering mode will require a different geometry which is why each steered wheel (not axle) has it's own steering hydraulic and valve gear. The best and most authentic way to replicate that would also be the most costly in this case as it would require multiple NXTs. having the computer work out and then control all the angles of each individual wheel is the most efficient, reliable and mechanically simple way of doing it, which is why they do it that way. If you want it all done mechanically then you will need what is basically a mechanical steering computer, like the ones you see in the various Jeep hurricane MOCs, such as my own unfinished but working version with 4 steering modes.

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=473387

Which steering modes do you have in mind BTW?

.

Edited October 18, 2015 by allanp

[750ACE]

Haven't you mentioned this idea repeatedly in other threads? I recall others responded with actual working mocs of equal size if not even larger.

To answer your question: yes a working model would be awesome.

[aminnich]

Haven't you mentioned this idea repeatedly in other threads? I recall others responded with actual working mocs of equal size if not even larger.

To answer your question: yes a working model would be awesome.

I started a concept thread, just to see what people thought. Only one actual crane was mentioned that has 12 axles, but im only going to get ideas from it, not base my build completely from it

Which steering modes do you have in mind BTW?

.

Im thinking the regular steering center around the 2 middle axles, and crab (including steering the middle)

The problem with doing the crab steering is that all the axles need the same turning radius, and if im doing the regular steering all the axles will have different radii.

[M_longer]

OK, maybe this way:

What's your experience with large models? Have you ever built something that was at least 4kg (or heavier)?

[aminnich]

I have built larger things, but im not sure how much they weighed

[allanp]

The problem with doing the crab steering is that all the axles need the same turning radius, and if im doing the regular steering all the axles will have different radii.

Ah, well that shouldn't be too complicated.

One way of doing it would be to have each steering axle connected to their own 2 speed gearbox (12, 2 speed gearboxes total). In the first position (crab), the ratio in every gearbox is the same, so they all turn the same distance. In the second position (standard steering), each of the 12 gearboxes has a different ratio, which would then turn each wheel by a different amount according to what ever ratio you have. This could be simplified a little by having only 6 gearboxes, gearbox 1 connected to axle 1 and 12 (as they would always bee the same angle), gearbox 2 connected to axles 2 and 11 and so on. But remember, when using the clutch gears there is some slack, so you will want to have a lot of gearing down after each gearbox to mitigate it. You will also need to make sure all wheels are steered straight ahead before changing between steering modes, otherwise they will go out of sync. Another way of doing it would be to have steering arms that change length, or an adjustable linkage that would give the same affect. This is more of a headache to figure out, but it has the advantage of not being able to go out of sync.

Edited October 18, 2015 by allanp

[aminnich]

That is actually i good idea, Im going to try this out

[dr_spock]

I would suggest searching Brickshelf. Go there and search on "crane". Many AFOLs have done monster size cranes in the past. Some have posted good detailed pictures of structures and mechanisms.

[aminnich]

I cant tell you how many ideas i have gotten from Brickshelf. Thats my go to problem solver

[aminnich]

searching through brickshelf, i found this. It is kinda hard to see what in the world is going on with all those gears, but from the pictures changing the steering can easily be done.

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=173522

[deehtha]

I forget where, but I remember reading about a 5+ axle crane that had 2 different steering rack on each axle. In steering mode 1 the racks that were configured for normal steering were engaged, allowing each axle to turn at the correct angle. In mode 2, the steering racks for crab steering are engaged.

All the steering racks were driven by same common axle. The steering axle was shifted by 1 stud to choose the steering mode.

[aminnich]

You are thinking of this topic; http://www.eurobricks.com/forum/index.php?showtopic=89963

[TheItalianBrick]

No offence or hard feelings amminnich but let me say, in my opinion, you do struggle with a normal/smaller crane, why would you even try to build a 12 axle crane?? Again looks like people want to impress with huge size model....but they all fail. Instead I think it's better to make something smaller but well done, well designed, well detailed and that works well. Also you seems to change constantly your mind! This makes you insecure and it won't lead to a good final result! Simply chose something that exists in real life, take blueprints, start from there till the end. No room for indecisions! Hope sometimes you will think about my words...

[MaxSupercars]

I would not discuss about it if aminnich (or someone of us) is able or got enough experience to build it...

I like the affirmation: "We are not doing things because they are easy but because they are hard..."

We all tryied a lot of things to do with Lego and some ended only as unfinished WIPs...

Aminnich started this topic to discuss how we can help him to archieve the result and we should concentrate to post comments that bring him a step further...

Max...

Edited October 19, 2015 by MaxSupercars

[aminnich]

Thank you max, that is exactly what this topic is for. I understand I'm not a professional like half of you, but I was like a Challenge when it comes to my head.

My building thoughts change all the time because I'm always thinking how it can be done better or more efficiently. I'm sorry if that is unsettling for you, but that's how I work.

Also, if u read the first post, it clearly says don't talk me out of building this.

Thank you to everyone who is supporting this crazy idea. I hope it goes well

[TheItalianBrick]

Sometimes to understand or to help someone to understand certain limits it's a step further.

Also, sorry but there is not much suggestions we can give, simply people has to try, try and try! It's the only way! How many 12 axles crane do you see out there? probably none...so best is to start to build and then ask suggestion on "how to take it from there". otherwise concept wise there is nothing special...just put 12 axles together and a boom on it!

I think it's good to ask suggestions, but on something that's actually at a reasonable level according to people's skills....

One more thing: Sariel opened a topic about useless topic: well I guess to google "12 axle crane" you don't need EB forum.....

P.S. Aminnich it's ok to "do it better and more efficiently" but so far I haven't seen a brick! Just words! Maybe you should start to show something....then this post would make sense!

Also a good thing would be starting with a 6 axle crane, see how it works, then from there improve it and adding axles....see what changes and how the structures react.....I never get things ar first try myself. But I try hard and before to ask I make sure I have something to ask about!

Edited October 19, 2015 by TheItalianBrick

[aminnich]

Honestly, if you are against the idea. You are not forced to post on here. Someone once said, "If you have nothing nice to say, don't say anything at all"

[TheItalianBrick]

LOL. why do you get angry?

I think people are always too nice right because they are afraid to say things as they are!

Anyway I'm not against the idea, I simply prefer poeple who "does" compared to "daydreamer". You will have all my support and I'll be happy to contribute with help when I'll see some bricks.....

[aminnich]

Your not the first person who has discouraged me on a build. I understand you think the project is too big for a builder with my experience, ok but that doesn't stop me.

As for the build, I'm focusing on my small contest entry now and school work. This 12 axle beast will be a very slow build, basically building on weekends. I could make a WIP topic, but it would last forever.

[TheItalianBrick]

Your not the first person who has discouraged me on a build. I understand you think the project is too big for a builder with my experience, ok but that doesn't stop me.

As for the build, I'm focusing on my small contest entry now and school work. This 12 axle beast will be a very slow build, basically building on weekends. I could make a WIP topic, but it would last forever.

in a way I'm actually encouraging you to build (I said I don't like words I prefer facts) so it's ok to have a slow build...it's actually even better specially when building huge complicates cranes there is no need to rush! Also the only way to increase experience is to build and try!

Anyway I do wish you good luck and again when I'll see some bricks then I'll will for sure help (where I can)