[MOD] 42009 Mobile Crane - MODs and Improvements

[Leif]

Dear all,

Based on the Ultimate 42009 and afol1969 extended and improved boom.

I wanted to create a boom that was strong for real, to be able to lift something.

Studded beams are of course part of the solution and after I bought the 8421 and the 8053 I was stocked up on these. I also bought some extra curved 11x3 from bricklink to be able to build at least a bit colorcoded!

I dare to say this is a strong boom!

5 panels long main boom.

5 panels long secondary boom. 4 panels can and should at most be extended.

2 layers of studded beams, fixed with diagonally unstudded, and another 2 layers of studded beams for the third boom.

the wire for third boom return is fed over the second boom racked gear, I find this a good solution for this wire. the second boom has small wheels at both ends for wire to run smoothly. I can post a pic of this tomorrow if someone is interested.

I actually used the 42009 cord as boom driver. strong and not elastic.

Reinforcements at the base of the boom, a lot of pressure here.

The boom is the one from afol1969 that we all know a lot about, but I have added one layer of beams to primary and seconday boom in order to fit the enforced third boom.

The lifting angle is quite good, the boom actually can touch the superstructure at max height. At the same time the boom can rest horizontally as well.

I think this is close to max what a boom of this length can achieve. The next model would probably need 3-4 LA for lifting and so much reinforcements so it would soon be too heavy for its own good!

more pics upon request and I now see that some of the pics have too much light, sorry for that!

Lifting the Unimog cabin, my benchmark!

Thin thread but strong. Still some color mixing on third boom..

A new idea for the propulsion of second boom, two worm gears directly on the racked gear. stable and simple.

Reinforcements, reinforcements! the diagonal 11 beam is moved to the outside of the triangle after this test.

My counterweight

Budging but holding..

[jantjeuh]

Love the design of your counterweight! Extravagant, but eyecatching. Also good job on the boom, it looks quite sturdy indeed.

[Rishab N]

I like the boom, but what if someone wanted to build it and didn't have that counterweight on hand

Edited September 8, 2014 by Rishab N

[Jim]

Merged the boom into this MOD topic.

[kamsohal]

looks good any more pics for inspiration?

[technicfan]

Man that is one busy table you have got there, looks good though.

[Leif]

Man that is one busy table you have got there, looks good though.

Yeah I've been stocking up om technic flagships and such for the last few months, got out of the dark ages this summer so it's been hectic...

I like the boom, but what if someone wanted to build it and didn't have that counterweight on hand

Love the design of your counterweight! Extravagant, but eyecatching. Also good job on the boom, it looks quite sturdy indeed.

The counterweight is mandatory so it is quite high part count on this MOC

the boom is really sturdy. Yesterday, without extending the boom but fully raised I was able to lift approx 1.2 Kilogram.

extended boom, the numbers will drop of course and I will try to build some kind of bucket that I can fill with coins or similar to be able to measure exact performance of different boom lengths.

I also need a better scale, has to measure below 1 kilogram. or just lift water, then I can do the math...

looks good any more pics for inspiration?

Sure, I will take some more, and better pics this (Swedish) night for details!

[Leif]

Some more pics of strong boom.

Driving second boom. two worm gears directly on the racked gear. sturdy and simple,

the cord for retracting third boom is attached under u-joint but you see the leftovers of the cord as well going out in the air. I haven't got the courage to cut it yet...

Here you see cord coming up and going over the racked gear. this cord is for retraction of third boom. via pulley of course.

Top of second boom with hook cord guidance as well

Lower end of second boom with pulley for cord for the third boom. White panels on purpose! dont go any further...

Third boom layed out

Third boom dissected

and in detail

I am not sure the diagonal beams in the third boom are 100% "Lego Legal". It may be 1 micrometer or similar misfit but for the time being...nothing forced I can promise!

[neoconagenda]

I too would be interested in knowing if it is a legal connection...

[Carlito83]

Amazing thread, thanks.

[Hrafn]

I am not sure the diagonal beams in the third boom are 100% "Lego Legal". It may be 1 micrometer or similar misfit but for the time being...nothing forced I can promise!

Off by just 0.6mm! 80mm in one direction, 9.6 in another; sqrt(80*80+9.6*9.6)=80.6mm and the beam is 11L so there are 80mm between the centerpoints of the end holes. There's probably no 'legal' way to do this since the boom section is so narrow.

[JuicedEagle]

Besides the electric things ( motors and receivers etc. )

Could a second 42009 get the missing parts for the ultimate?

Any suggestion for the most stable boom here on the forum?

New to this technic modding, and just finished my 42009 yesterday!

[therealjustin]

I made a few small improvements last night to my 42009. The rear superstructure has been raised and extended by one stud so as to match the front cabin height, and it now sits even with the boom.

[JDC]

That is a nice improvement. Where did you make the change?

[kisper]

Hello :)

Newbie signing in here. . .

Got myself the 42009 and found out that the single L motor is a little weak to power the whole system. I was wondering if by using a XL motor, it might work better ?

Also, I just finished ordering the parts for the extended boom and eagerly looking forward to its arrival to start this awesome build :D

[Jim]

Hi,

Welcome to EB!

Using the XL motor means more torque, but less RPM, which will make the functions even slower. Another option would be to collect the parts for Jurgen's Ultimate 42009.

[kisper]

I am still quite confused about the torque and RPM thing

[Jim]

Simply put; torque relates to power/strength and RPM (rotations per minute) relates to speed.

Lookup both terms on Wikipedia/Google for more information.

[Blakbird]

Got myself the 42009 and found out that the single L motor is a little weak to power the whole system. I was wondering if by using a XL motor, it might work better ?

Most of the reviewers (including myself) have not found the L motor to be underpowered in this application. Rather than adding more power, perhaps another tactic would be to review your build and see if there is friction in the system that can be eliminated. The way the model is built can have a big impact on the performance.

[kisper]

@Blakbird : May I ask where I should check for friction ?

[750ACE]

@Blakbird : May I ask where I should check for friction ?

You will find in almost all technic instruction booklets a small diagram that states all gears on an axle with another bushing or gear should not be forced together to tight. It is a small picture with an X for wrong and a check mark for right.

[kisper]

@750ACE : Yes I did follow that instruction :)

[Electricalchief]

So I just want to get this cleared up. I found from the TechnicBricks review that to balance the "load," you need to have the 20t gears facing the same want, and not facing each other. But if that's the case, how come the reviewer still did it the way it's written in the instruction booklet?

O did this in mine and i think that i have more crank than in original setup. May the MK had this in mind and did the setup as he did.

Also i would like to mod this crane just for move and steering rc functions. Which motors have to use ? Is any set that could buy for using these parts?

[DrJB]

I am still quite confused about the torque and RPM thing

The electrical motors (and many other transducers) output POWER (not rpm, nor torque). Essentially, they are power transfer devices and they take electrical power (watts=current×voltage) and make it into mechanical power (watts=torque×rpm or watts=force×speed). As such, all these devices have what is called an output characteristic i.e., what is the max rpm they can output for a given torque (or vice versa). Typically the larger motor will output higher power (not necessarily faster speed) and you need to decide what exactly you're after. If you want to spin something that has very little friction (e.g. spirographe on this site), then a small motor (M/L) will do. However, if you want a motor to lift the heavy boom of a modded 42009, you may need either an L or XL motor. Hope this makes sense, else, ask again.

Edited December 9, 2014 by DrJB

[bonox]

perhaps a better way would be to say that power is the product of torque and angular speed. (P = T * w)

For any given motor, power (P) is always fixed, but you can get more torque (T) by gearing down (ie you can get more twisting 'force' which is called torque) but at the penalty of lower speed (w). Or you can get higher speed by gearing up (more output turns for a given number of input turns) at the penalty of reduced torque.

The downside of changing the gearing is a loss of power which goes into friction of the gears/axles etc.