Jennifer Clark's Demag AC-50 Crane

[Alasdair Ryan]

I worked out a 4-stud x 4-brick 3 section boom many years ago - difficult to motorise with LA though: http://www.brickshel...ery.cgi?f=27182

I would be using a dummy LA (it would not be motorized),my sketch can be found in the previews page.

[nychase]

Let me tell you about a little project I called the Demag Mammoet Edition:

Last year I was talking with Blakbird about possibly building the new "Grove" version of the 42009 crane and if it was worthwhile. While he said it was, it got me thinking that it was such a shame that the Demag didn't have a proper 3 section boom (lets ignore that "proper" would actually be 5 section). I took a good look at it but always remembered that Jennifer wrote it off on her initial build because it would of required a 6 stud wide construction which was out of scale.

Well, after endless hours of design, testing, design and more testing (I think about 60 hours total), I have made the fabled but never seen in existence 4 stud wide, 3 section LONG motorized boom. Make no mistake, this thing is an absolute monster, the crane now stands 52" tall at full extension (132cm). It all works near perfectly as well (which was a requirement to be on the model in the first place). What was achieved is a boom nearly identical to the original being only one plate taller. The mount axis point, ram attachment point and the retracted length are the same as original. I actually removed one of the three fake 7 beam booms from the outer boom and moved it in proper spacing to becoming real for the middle boom, now it actually performs as it looks!

Is it perfect?...no. I was unable to get a limitation on the extension other than it running out of track. It still sits perfectly when that happens and will retract properly so long as its anything but completely horizontal. I considered it a fair trade-off. Also, there is significant friction given so many parts rubbing against eachother but as long as the inner boom strings are properly routed the friction isn't enough to stall the motor. Certainly it doesn't have the same load capacity at max extension but it can still lift quite a bit more than you would ever expect. The Firgelli Actuator can still fully lift the boom at max extension from full horizontal which is incredible.

The rest of the design is mostly color changes though I did add two boat weights to the back of the super structure. I would have loved to add more but I guess I wasn't in the mood for a full redesign of that too.

I did actually create the ldraw for the 3 section boom in white too but I don't believe instructions have been made for it....you'll have to ask Jennifer and Eric if you want them made.

Edited September 24, 2015 by nychase

[kisper]

Beautiful crane ! Do u have a video of its functions :)

Thanks

[Milan]

I have made the fabled but never seen in existence 4 stud wide, 3 section LONG motorized boom.

I think there are few four studs wide boom with 2 extendible sections, (3 sections total),

There is a cable on first picture that extend section, probably not motorized, but could be easily with one M motor.

Nice to see two solutions for the same problem!

Great work on your side! Jennifer model is a great base, and you have improved it even more!

[nychase]

I think there are few four studs wide boom with 2 extendible sections, (3 sections total),

There is a cable on first picture that extend section, probably not motorized, but could be easily with one M motor.

Nice to see two solutions for the same problem!

Great work on your side! Jennifer model is a great base, and you have improved it even more!

Not to be offensive but I was specific in saying motorized for a reason. That very boom and crane were mentioned just 3 posts ago and I wanted to highlight that this is fully motorized and actually very strong. Given the sag you can see in that design unloaded I can't imagine it can hold much of anything.

Its important to note though that this never would have been possible in 2003 for Jennifer. Most of the parts I used were designed (or redesigned) in 2010 or later and without them it wouldn't have been possible.

[Milan]

Sure, i did not mean to be offensive, neither. As I said, very nice work, on very nice base model.

[bonox]

wow - looks great chase. Having just built the two section, i'd be keen to put a 3 section together as well - and probably keep both with the crane for amusement.

[Jennifer Clark]

Amazing work Chase. It's great to see the model evolve.

Jennifer

[nychase]

Because I just seemed to find out about Sbrick....

Does anyone know if the "foil" trick will work for it. Rather, can an Sbrick properly get power from Older 9V battery boxes as-is or do you need to trick (or wire it) it like you do with PF IR receivers?

Yes, I'm considering upgrading to Sbrick on this model because its one of the few downsides in that it has 7 functions but 4 of them are buried in the base and don't have the best lines of sight (reliable operation). Also, it should cut down on some wire/extensions which should free up some valuable wire space that otherwise pushes on the drive axles (Both versions I've built broke a drive axle gear within 5 minutes and if you know this model then you know its never going to be replaced unless I rebuild it completely.

[Blakbird]

SBrick uses PF wires, so it would require the foil trick to get power from the old 9V battery box, but it should then work. As a bonus, each unit has 4 channels instead of 2 so you don't need as many of them.

[2LegoOrNot2Lego...]

Would it not be possible to have a PF extension wire and a old 9V system extension wire connected? After all it is possible to integrate both systems because of the PF extension wire having this 9V systems connection on the bottom of one of the connectors...

Just a thought, I am no longer into that older system...

[Blakbird]

That's what we are talking about. However the PF IR receiver doesn't use the same two terminals as a motor, it uses the other two terminals. To make it work with a PF extension wife you have to bridge the terminals with some foil. SBrick works the same way. This ensures the receiver is always on and is not effected by the polarity or setting of the battery box.

[Lego2016Lego]

Cool.

[Milan]

...PF extension wife...

Wow, didnt know this is available! Great find! :)

[2LegoOrNot2Lego...]

That's what we are talking about. However the PF IR receiver doesn't use the same two terminals as a motor, it uses the other two terminals. To make it work with a PF extension wife you have to bridge the terminals with some foil. SBrick works the same way. This ensures the receiver is always on and is not effected by the polarity or setting of the battery box.

Okay, that makes sense...I now about those terminals, well that they exist, but for me that is about it...I am not that much in to electric stuff... :laugh:

[jkpark]

L12 EV3 50mm or L12 EV3 100mm

whichever of the two is?

and EV3 100mm , Cable nxt to pf is out of stock :sick: :sick:

I want to make ac-50 crane~~~~~

Edited July 2, 2016 by jkpark

[bonox]

they are unable to get PF connectors any more, so they have stopped making the cable. It's always out of stock and probably won't ever be available

[zux]

If understand correctly you need to connect NXT with PF. In such case if you have PF extension cables you could use one of these. Yes, there would be more cables, but it works.

[Blakbird]

Or make your own.

[RoscoHead]

I have also constructed a 4-section boom that is approx. 12 plates wide and 6 studs high.

4-Section Boom

[RoscoHead]

On 9/25/2015 at 3:52 AM, nychase said:

Given the sag you can see in that design unloaded I can't imagine it can hold much of anything.

1. Here it is lifting it's own trailer, fully extended, at a fairly steep angle.

2. After seeing how much real telescopic crane booms sag, I was pretty happy with the result.

[AFOLegofan66]

nice job. I have this crane in white, and it works flawlessly. Thanks Jennifer.

[Actuonix]

First off, this crane is one of the most impressive lego builds that I have ever seen. Congrats on the amazing build!

I also wanted to mention that the company that sells the linear actuators (Firgelli) has rebranded and is now Actuonix Motion Devices. The LEGO actuators are still available and can be found here: https://www.actuonix.com/lego-actuators-s/1929.htm

Cheers!

Mike

[Blakbird]

2 hours ago, Actuonix said:

First off, this crane is one of the most impressive lego builds that I have ever seen. Congrats on the amazing build!

I also wanted to mention that the company that sells the linear actuators (Firgelli) has rebranded and is now Actuonix Motion Devices. The LEGO actuators are still available and can be found here:

Thanks for letting us know; I'm not sure I would have found this otherwise.  Do you still offer an adapter cable for Power Functions?  Also, do you still offer a conversion to lower gearing?

[bonox]

 

I built mine with an eye on one parked locally. There is the odd photo of this slightly different axle configuration  on the webs, but at least in this country, they seem to be very thin on the ground. My suspicion is that it's due to the axle loadings required to carry the additional ballast over the forward power pack. Nevertheless, after some help from my employer, i managed to get a photo opp with the real one after 5 years of umming and ahhing about it. Might be time at last to modify the model to match the real one.

Edited August 6, 2017 by bonox