Jennifer Clark's Demag AC-50 Crane

[Alasdair Ryan]

Blakbird can you tell me the rough weight of the boom?

[Jennifer Clark]

I only recently received the final version of these instructions, and Eric & Chase have done a fantastic job.

You can download them exclusively from MOCPlans for the introductory price of only $15 by clicking here. The price will increase a month from now, so don't hang about :-)

Enjoy, and I look forward to hearing your feedback on them!

Jennifer

Edited May 21, 2014 by Jennifer Clark

[Alasdair Ryan]

I just bought them,the instructions look fantastic.

I look forward to building it.

Edited May 21, 2014 by Alasdair Ryan

[skriblez]

I might have to get them but i think i might be a bit "new" to be able to build it for a while :P

[dr_spock]

Thanks Jennifer. Is that $15 US Dollars?

[Jennifer Clark]

Thanks Jennifer. Is that $15 US Dollars?

Indeed :-)

Jennifer

[Blakbird]

Thanks Jennifer. Is that $15 US Dollars?

We also accept the giant stone coins of Yap Island, but you are responsible for getting them to us.

[skriblez]

How many of those Yap coins? 15?

[legolijntje]

How many of those Yap coins? 15?

You get a discount when you pay with Yap coins, so it will be 14,95 Yap

But, about the model, it looks wonderful, but I suppose that was already a fact after all these years.

This time, a lot of effort and time (I know how much time it can take) was put into the instructions by Blakbird and chase. And, let's not forget Jennifer of course, she built the original model. So, thanks all!

[skriblez]

Awesome! Ill get right on acquiring those coins!

[ritztoys]

Blakbird can you tell me the rough weight of the boom?

I'm not Blakbird, but my boom isn't attached right now, due to 11 years of WIP. My boom ( with 9V motor in the structure ) is approx. 500gr. Hope that helps............

[Alasdair Ryan]

Thank you very much for that.

Here is my idea for the boom improvements.

Edited May 22, 2014 by Alasdair Ryan

[nychase]

Thank you very much for that.

Here is my idea for the boom improvements.

That an interesting idea for sure...but I am not sure how strong it would be able to be.

It already has to be a shockingly strong boom to just lift 1lb.

Even though its a 2-part boom it is impressive in height...there is very little waste between the two sections. I don't know exactly how tall but I am sure that Eric and post a few comparisons to other cranes.

[Jennifer Clark]

It already has to be a shockingly strong boom to just lift 1lb.

Indeed so - when it is not telescoped, the crane could lift 1kg or 2.2lb -

Before I build this crane I had figured out how to build a telescoping 3 section boom, see the link to my website below - scroll down a bit for the prototype;

http://www.genuinemodels.com/ideas.htm

I didn't use it because it would have to be 6 studs wide to retain sufficient strength, which would have ruined the proportions of the model. Not just the boom, but then the superstructure cab would look too thin, which would mean widening the superstructure, which may or may not mean widening the carrier, and so on :-)

The correct proportions make the boom 4 studs wide - perhaps it is possible to make a sufficiently strong version of this width with modern lego parts? Or accept a lower strength?

Or the model could always be adapted to have the 6 wide boom if you can accept the aesthetic penalty. Or you could build a lattice boom extension. The choice is yours - that's the beauty of Technic :-)

Jennifer

Edited May 22, 2014 by Jennifer Clark

[Blakbird]

Indeed so - when it is not telescoped, the crane could lift 1kg or 2.2lb -

Was the lift capacity limited by line pull or boom luffing? In other words, I can see that the winch was capable of lifting that weight with the boom in a static position, but could the lead screw actually lift the boom with that weight applied? In my experience, cranes virtually never do this. The boom is raised into position with no load and all the lift is done by the winch.

[Jennifer Clark]

Eric, I honestly can't remember! I suspect the leadscrew could not luff the boom with 1kg, although it could certainly luff lower weights. What the threshold was, I have no idea, but the leadscrew was pretty powerful.

I think the limiting factor for lifting was the turntable, since I could not find room to make a thrust bearing for slew. Increasing the load beyond 1kg made it tend to lurch on the rollers, with associated oscillation of the load. This could probably be balanced out by increasing the counterweight, but then, that would slow down the drive speed due to added mass :-)

Jennifer

[Alasdair Ryan]

This could probably be balanced out by increasing the counterweight, but then, that would slow down the drive speed due to added mass :-)

Jennifer

Today's PF motors are more power full than the motors you had available.

Edited May 23, 2014 by Alasdair Ryan

[2LegoOrNot2Lego...]

Nice to see this amazing MOC has BI available, thanks to all who are involved!!! I am sure these instructions look amazing as well, keep it up!

I reverse engineered this model years ago, I think its' been in the 'box' for eleven years May I present mine ( not completely finished ).......................

Well you did manage to get it done this far, I would say you would only need about 10% of the BI...haha... :laugh: I am kidding, I am sure you love the BI of this beauty too, have fun building it and collecting its parts of course

[Jennifer Clark]

There's now a very informative article about the instructions on TechnicBricks, check it out!

http://www.technicbricks.com/2014/05/building-instructions-for-jennifer.html?spref=fb

Jennifer

[Duq]

Hey Jennifer! Good to see you here! I've fond memories of playing with your models in Geldermalsen. Hard to believe that's 12 years ago...

Gonna have to build the crane. Been meaning for ages to have a go at modding it for PF but life keeps getting in the way ;-)

[Jennifer Clark]

Cheers Duq, good to hear from you. Time flies!

I see you are an ambassador, nice one, go steady on the Ferrero Rocher :-)

Jennifer

[Captainowie]

We also accept the giant stone coins of Yap Island, but you are responsible for getting them to us.

But according to that very article, no physical movement of the stone is required - all I have to do is have it properly recorded that the stone belongs to you now. You are then free to move it yourself if you so desire. :-)

[skriblez]

But according to that very article, no physical movement of the stone is required - all I have to do is have it properly recorded that the stone belongs to you now. You are then free to move it yourself if you so desire. :-)

Great plan! Let's try it and if we have to move it we can probably use The Fox!

[Duq]

I see you are an ambassador, nice one, go steady on the Ferrero Rocher :-)

LOL! That's not easy being the chocoholic I am...

[RoscoHead]

I think I have found a way to add another boom section by using brackets,this would still keep the boom the same size.

I have a idea for the boom raising too but this requires testing.

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