42009 Extended Boom

[afol1969]

Hi all,

I've got the LFX file from a member of the french Technic Forum (www.techlug.fr) for an extended 42009 boom. But as the step order isn't very clear (I had to dismantle the boom two times to place the right parts), I've recreated the instructions with MLCAD, and here are the results:

https://www.dropbox..../Boom 42009.mpd

https://www.dropbox..../Boom 42009.pdf

Feel free to build and give me information if the instructions contain any errors.

Best Greetings

Alex

Edited February 21, 2014 by afol1969

[Jim]

Thanks!

I still need to buy the crane, but I will save this for future reference

[Foggy]

me too ;)

[skriblez]

Thank you, will save it and see if it can't be built into Jurgens Ultimate :)

[Jim]

Jurgens Ultimate combined with this Extended Boom sounds perfect!

[afol1969]

Thank you, will save it and see if it can't be built into Jurgens Ultimate :)

The boom doesn't depend on the construction of the crane base, so it can be built in the Ultimate 42009:

Greetings

Alex

Edited November 14, 2013 by afol1969

[Jim]

This topic makes me want to buy and build the crane

[Balrog]

Jim: The crane is definately worth building. I didn't even get bored for a second.

afol1969: thanks for the instructions. I'll store them as well for now. I don't think I have enough panels (since 8 of the new curved panels are needed) nor in the correct colors ;)

How stable ist this boom compared to the original boom when fully extended? E.g. how wobbly, stiff or easy to bend is it?

[Jim]

Jim: The crane is definately worth building. I didn't even get bored for a second.

Cool

The old crane got me back from my dark ages in 2005, so I was really looking forward to this one. But slowly my interest decreased, knowing that I would buy it some day, of course. It's a little bit higher on the list again

[afol1969]

Jim: The crane is definately worth building. I didn't even get bored for a second.

afol1969: thanks for the instructions. I'll store them as well for now. I don't think I have enough panels (since 8 of the new curved panels are needed) nor in the correct colors ;)

How stable ist this boom compared to the original boom when fully extended? E.g. how wobbly, stiff or easy to bend is it?

Hi Balrog,

The full lenght of the extended boom is 105cm. But it's rather stable, more than the boom in Han's 8421xl. It's just the 2nd segment wich bends a little from the first segment, if fully extended. But in general panels give more stiffness than beams/technic bricks, and there is no bending. I haven't tried it, but maybe you can get more stiffness if you use the older black long pins with friction.

But you need more counterweight, that's why I connected a second BB, and used some more beams to stabilize the slew construction. For the cable inside the boom I used the original hook cable, for the hook drive I used a more fine cable for easier driving.

How to attach the cable, is shown in the instructions. And it's not necessary to use the 10 hole panels, the 4 hole panels can be used as well. This note you'll find in the instructions too.

Greetings

Alex

(sorry for my bad english)

[Rishab N]

Nice modification! Could you show pics of the boom fully extended?

[afol1969]

Here the crane with the full extended boom:

[Balrog]

It's just the 2nd segment wich bends a little from the first segment, if fully extended. But in general panels give more stiffness than beams/technic bricks, and there is no bending.

Ah I see what you mean in the picture. I guess the problem lies withing the flat bottom of the second stage and that being just held in place by a single gear. There must be a lot of friction on the gear and gearrack at this moment. No easy task to improve that!

Thanks for the detailed answer. Your english is well enough I would say.

[afol1969]

Ah I see what you mean in the picture. I guess the problem lies withing the flat bottom of the second stage and that being just held in place by a single gear. There must be a lot of friction on the gear and gearrack at this moment.

Exactly.

But thanks for your information, that gives me information to find a solution. Maybe the problem could be solved by a second gear, but that will give some more friction. I have to test it.

Greetings

Alex

[Balrog]

I might have an idea that would make the second stage more stable. Something like a rail which has a counter-"hook" below the first stage. But, that would require a open center of the first stage bottom. And that in consequence would make the first stage unstable and is likely impossible to build because of the mountpoint for the LAs.

I guess if one could build it (like it is in my head) and make it stable enough, that would make the first stage at least a lot more massive.

[therealjustin]

I just built this extended boom and I'm curious about a couple things. Is anyone else's last section of the boom able to be pulled out completely? On mine, this end section can be pulled out and left dangling by the string in both extended and retracted states. Also, when you retract the boom does this last section require you to push it in the final few inches? Maybe I did something wrong?

I cannot for the life of me figure out how I was suppose to attach the string at the bottom of the largest section so I just took a gray bushing and tied the string around it and tucked it up in the cavity.

[therealjustin]

In this short video you can see the issue. When the last section is nearly retracted it sticks because of friction. Not sure what the problem might be. Also, the photo shows this final section and how it can be pulled out.

http://www.youtube.com/watch?v=jaBL3Qv3l18&feature=youtu.be

[afol1969]

Hi Justin,

I'll try to help you to solve the problems

- 1.) It seems that you have used a cable wich ist too short. But I'm not sure...Try to take a longer cable, and cut it in a final step when fixed at all sections.

- 2.) Maybe it's caused to a wrong cable placement

- 3.) Block the string in section 1 like shown on the picture, pass through the 1/2 pin and block with the red axle 2

Wich instructions you used? the ldd file or the pdf file?

Explanation for the cable placement:

Use a cable of minimum length 50cm

- Attach the cable at the end of the section 3.

- Pass the cable through the pulley

- Insert section 3 in the section 2.

- The cable must pass through the center (holes) of 1x5x11 panels

- Fold the arms fully

- Once the cable placed, secure with pin ½ and block to the end of the main section with a axle 2.

Greetings

Alex

[TinkerBrick]

An even longer boom would be nice, no question.

But imho, i'm a not to happy with the mounting point of the boom. I built both the regular and Jurgen's ultimate version of the 42009.

The original mounting point for the boom is located rather just behind the operators cabin. But when i look at real life cranes, the booms are mounted further to the counterweight with just the winch drum located between the joint and the counter weight. Actually the place were the IR receivers sit would be ideal. This balances the boom and turret better esp. under weight.

Has anybody tried to redo the turret and mount the boom further to the back? I know this would mean to totally reengineer the turret regardless of the version.

But it would look more realistic.

[therealjustin]

Wich instructions you used? the ldd file or the pdf file?

First, thank you for the help Alex!

I used the PDF to build the boom. I went through the LDD file and made a list of the pieces I needed before you made the PDF, so some of my parts are different like sections 2 and 3 which are yellow. Also, the 32L axle support is different(styled like in the LDD file) and a few tiles are different lengths(1x8 instead of 1x4, etc). Nothing that would cause mechanical issues though.

In my video it appears that section 3 does not retract all the way but it does. Friction is causing it to not retract fully the last couple inches by itself and only does if I push it in manually.

-First I tied the cable onto the end of section 3

-Then I put that cable through the front of section 2(inside 5x11 panel holes) and out through the rear

-Lastly the cable was pushed through the hole located at the bottom of section 1 and secured with a black pin. I don't see any red axle...

This is how I looped the cable:

Edited December 10, 2013 by therealjustin

[Lipko]

I'm surprised that the two linear actuators can lift the boom at all.

[afol1969]

Also, the 32L axle support is different(styled like in the LDD file) and a few tiles are different lengths(1x8 instead of 1x4, etc). Nothing that would cause mechanical issues though.

That's right. If I make instructions, sometimes I do make some little modifications on my own - but not too much.

In my video it appears that section 3 does not retract all the way but it does. Friction is causing it to not retract fully the last couple inches by itself and only does if I push it in manually.

Which kind of cable you used, and which thikness?

-First I tied the cable onto the end of section 3

-Then I put that cable through the front of section 2(inside 5x11 panel holes) and out through the rear

-Lastly the cable was pushed through the hole located at the bottom of section 1 and secured with a black pin. I don't see any red axle...

This is how I looped the cable:

The cable loop is correct, so I cannot see at first moment where's the problem. I've built the boom, and dismanteled it for the instructions, and rebuilt ist.In both cases I didn't have problems with the boom functions and cable loop....

Greetings

Alex

[therealjustin]

Lego did not have any of their normal string in stock so I purchased some beading string at a local store. It is almost identical to the official string found on the 8110 Unimog winch but a bit more silk-like.

The problem must be friction because the way this boom is designed, section 3 needs gravity to retract since there is no return cable. For example it will not retract the last section if the boom is completely horizontal. If I could find a solution for that it would be great! There was a member on Techlug under the username "Jacques27" but he seems to have left for good sadly. His 42009 projects had a return cable or at least it looks like they did.

[afol1969]

Yes, I know him, I'd mail contact with him to ask his instructions, which I converted in a pdf file. He has left the forum for some reaons which are not clear.

I've built the boom with the LDD file, and it worked well. Then I dismateled it to recreate the instructions in LDRAW, and I rebuilt ist. In both cases I'd no problems with friction/retraction. Maybe some beams are fixed not very correctly that can cause some bending that results in friction. Look at all pins/axles if they are pushed in correctly.

I've used the original cable from the set 8421, it's rather thick, but it causes no problems.

In worst case, you have to dismantel the boom and rebuild it.

Greetings

Alex

[therealjustin]

I tried a few different ideas today and found that if the cable is thin enough, you can add a return cable beneath section 2. I added a pulley to the rear of section 2 similar to the front but without the 3L axle and half bushings. Instead I used a frictionless tan pin. Tie a cable to the end of section 3(same spot as the other cable is attached) and run it through section 2(not through the 5x11 panel holes!). Next bring the cable underneath section 2 and dangle it in front of section 1. Insert all sections as they would be if the arm were retracted and secure the cable with a pin.

It works perfectly! There is little friction between the cable and smooth plastic panels so I don't think this would cause any problems unless you use the crane daily, of course. Now the boom can retract without the need for gravity.

Edited December 12, 2013 by therealjustin