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Updated version of Jennifer Clark's Demag AC50

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#1 Saberwing40k

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Posted 03 January 2013 - 12:53 AM

Here we go, I'm attempting to make an update of Jennifer Clark's legendary Demag AC50, and I have some questions to ask about the model. I want it to look similar, although updated to the best Lego currently has to offer, and with no modified parts.

The questions are as follows:
Where is the battery box for the carrier located?
How big is the model?
What goes in the section behind the front wheels?
How tall is the boom?
How many studs are between each axle?
How long is the leadscrew used to raise the boom?

This is all stuff that I was not able to determine from the pictures, so this is why I'm asking. The help of anyone who has built this model, or even the designer herself, would be appreciated.

also, I have made a new, driven and steered front axle, but I'm not sure if the current drive I've come up with, which includes a lockable differential, will fit. I'm planning on moving the drive motor to the front, just behind the front axle, but I'm not sure if that will fit either.

Any help is appreciated.
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#2 DLuders

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Posted 03 January 2013 - 02:08 AM

Here is Jennifer Clark's webpage for her Demag AC50-1 All-Terrain Crane :  :thumbup:

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For the picture below, she wrote:  "A 9V motor, battery box and several coins reside within the counterweight of the Lego model giving a total of 250 grams, equivalent to 2 tons in the real world. The motor used for telescoping is located at the bottom of the boom and will also add some weight. Making the counterweight heavier would be easy, but it would put more strain on the drive motors."

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Edited by DLuders, 03 January 2013 - 02:08 AM.


#3 Milan

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Posted 03 January 2013 - 02:13 AM

1. Behind the cab of the carrier
2. About 72 studs, carrier 61 studs in length, 18 studs wide, not counting outriggers's pads, 25 studs height, 35 studs width with outriggers deployed.
3. Part of the mechanism that drives the outriggers
4. Boom itself is about 68 studs long, in transport position.
5. 18 studs between first and second axle, 9 studs between second and third axle.
6. Leadscrew is about 22 studs long.

Not 100% accurate, but it is helpful until designer of the model comes.
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#4 Blakbird

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Posted 03 January 2013 - 02:45 AM

View PostSaberwing40k, on 03 January 2013 - 12:53 AM, said:

Here we go, I'm attempting to make an update of Jennifer Clark's legendary Demag AC50, and I have some questions to ask about the model. I want it to look similar, although updated to the best Lego currently has to offer, and with no modified parts.
.....................
Any help is appreciated.

Luckily for you, someone has already done this project!  See this post.  I'm sure Richard would be willing to help you.

As for your specific design questions, Jennifer has some LDraw files on her web page that you can download.  They are not complete, but they contain a good chunk of the chassis and should answer most of your questions.  Here is what I have cobbled together from the available files.  I added the flexible parts with the intention of making a render of this model.

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#5 SheepEater

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Posted 03 January 2013 - 02:53 AM

Love the pure studfull construction :wub:

Edited by SheepEater, 03 January 2013 - 02:53 AM.


#6 Saberwing40k

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Posted 03 January 2013 - 03:12 AM

Well, thank you all very much. Now, I'm wondering one thing: would it be sacrilegious to make it studless? I'm thinking I'd just make the chassis and stuff studless, and make the rest model team style. Also, I plan to include some improvements, namely better outriggers, a 3 section boom(maybe), and drive on all axles. And the motors will be new PF ones, not old 9v ones. I personally hate those, and studfull construction is somewhat more difficult. That way, everybody can get i non the action. However, the conversion might make it more of my own creation than hers....
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#7 nychase

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Posted 03 January 2013 - 05:32 AM

View PostBlakbird, on 03 January 2013 - 02:45 AM, said:

Luckily for you, someone has already done this project!  See this post.  I'm sure Richard would be willing to help you.

As for your specific design questions, Jennifer has some LDraw files on her web page that you can download.  They are not complete, but they contain a good chunk of the chassis and should answer most of your questions.  Here is what I have cobbled together from the available files.  I added the flexible parts with the intention of making a render of this model.

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Richard really would be the best person to contact about this project.

As you can see in that other thread he already accomplished much of what you would like to do.

Part of what makes the model so great is the studded construction of the undercarriage so it would be a shame to convert it to studless.

I have collected all the parts needed to build Eric's screenshot above but I will be making some of the changes that Richard made in order to modernize some of the components.  I already have the Firgelli Actuators (which I have talked about in other posts) needed to swap for the main boom (instead of Jennifer's Lead Screw design...which Richard was lucky enough to have machined for him).

The only other challenge is the boom extension...but I can't really say for sure if I can make it work (without the other proprietary lead screw) until I build it in person.  ( I have exhaustively examined the CAD's but can't be sure)

My end-goal was very similar to yours in that the changes I make could be sent over to Eric and have him (with Jennifers cooperation) eventually get instructions going with off the shelf parts (except for that actuator!).

I will get going on this project since I have been dying to build it.
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#8 Pvdb

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Posted 04 January 2013 - 11:10 AM

Quite a few years back I had a go at making Jennifer Clark's Demag, got 3/4 of the way then ran out of pieces and time. When eventually I dug my project out of the box, I decided to take a different approach and create my own completely new version with pendular suspension, ability to lock suspension on the rear whees, all wheel steering, and the ability to select between crab steer and normal steer, plus different outriggers/mechanism/drive.  I also removed the motorised drive and steering and put in place a technic engine.

http://www.mocpages.com/moc.php/301219

To be honest it was much more fun using the original model as inspiration, for a virtually new creation, (not to many bricks/parts remain in the same place as the original)

A lot of compromises had to be made to allow the switch between steering modes, and this feature has reduced drivability and means that I can't let my 4 year old loose with the crane!!!! I would like to remove this feature, spring the suspension, and remove the non-lego lead screws somehow, so perhaps when I finish my current project that will be the next one!

#9 me00rjb

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Posted 04 January 2013 - 10:04 PM

As noted by Eric and Chase, I did indeed have a go at this particular crane.  I started with the MLCAD files posted by Jennifer on her website, and filled in the missing bits from there.  I got as far as I could with the CAD model (which Eric added the flexible parts to, and did produce a render of: http://www.brickshel...y.cgi?i=5374051), and then made a start on building it for real.  Some adjustments were necessary, and I updated the CAD to an extent as I went along.  I stuck with the old style 9V motors, and incorporated Power Functions IR control rather than the RC of the original.  This required a bit of rebuilding, but I like to think I kept the model recognisable as the original.  I had a mate machine the actuator (which I have only recently painted - I really must get it finished and assembled!) and made the lead-screw for the boom extension from threaded rod.

I was considering getting a small batch of actuators and lead-screws machined up, but haven't had a chance to progress this recently.  If there was enough interest, I could give it a go.

In terms of modifying the chassis to studless and using the PF motors - well, it's certainly not impossible, but you would be starting from scratch effectively.  No doubt you could keep the look of the original, and re-work the mechanics.  The studded construction is very densely build; there's no spare room and everything only just fits.  If you moved one thing, it would have knock-on consequences for other things.  I'd love to see a modern version build with instructions, but the chassis / carrier is one big, dense lump.  Making instructions for it as it stands would be a huge challenge!

If you have any specific questions, just let me know.

I'll have to see about sorting out the additional pictures I promised last year some time...

Richard.

#10 Jennifer Clark

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Posted 06 January 2013 - 12:06 PM

I'd love to see these developments!

The original battery box was one, eventually two of the small 9V PP3 battery boxes placed behind the cab between the various greeblies.

After a while I changed this to a custom battery box of the type you can buy in Maplin containing 8 rechargeable AA batteries for a total of 9.6V, in two rows of four. This was able to deliver much more current than the PP3, and with the slightly higer voltage drove the model faster and more powerfully.

Jennifer



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