42009 Mod - new gear boxes




Additional to my new gear box for the superstructure of the 42009 Mobile Crane MK II I modified the undercarriage in that way that the complete model has now the following functions:

  • lifting/lowering the boom (L-motor #1)
  • extending/retracting the boom (L-motor #1)
  • rotating the winch (L-motor #1)
  • extending/retracting the outtriggers (L-motor #2)
  • lowering the outtriggers (L-motor #2)
  • rotating the upperstructur 360+ degrees ((L-motor #2)

Each function can be controlled independently and simultaneously. Furthermore, the direction of each movement can be changed without switching the battery box.

Update 2019-12-19:
For those having the problem that the motor stops when lifting the boom: jb70 solve this by using only one L-motor for all functions (link). Additionally he made instructions for the complete model :-)
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Name 42009 Mod - new gear boxes
Designer Mowlwurf
Designed 2019
Inventory 2732 parts
Theme Technic > Model > Construction
Modification of 42009-1 Mobile Crane MK II


  • 3 months, 2 weeks ago jb70 Level 16 MOC Designer PRO
    Very nice design!

    I like this kind of operating a gearbox: Technic like reality! The motors are always on. You use one switch per function to switch forward / idle / backward. It is the same principle as in Red Excavator based on yannmar's design.

    Thankx for sharing your LDCAD file. I used it as a base for my MOC and added PDF instructions with LPub3D.
    • 3 months, 1 week ago Mowlwurf Level 10 Designed this MOC
      Thanks for improving my design AND the instructions!

      I observed the stalling of the motor when lifting the boom as well but I ran out of ideas to solve this. I wouldn't have thought that the usage of two L-motors is the problem. But you're right - one motor is enough for all functions.
  • 6 months, 3 weeks ago hollaender Level 7 MOC Designer
    Really great mod. I already built your version of the superstructure.
    Question: I'm able to import this mod into stud.io. But do you have suggestions, how I can build the model out of it?
    • 6 months, 3 weeks ago Mowlwurf Level 10 Designed this MOC
      I've made the model with LDCAD and added steps for the building process.

      When you import the model into stud.io you should see the steps on the right side of the program. Therefore you should be able to step through the building of the model. For more information please look here and in the manual within the application.

      I hope this helps. Sorry for not providing a pdf instruction - I don't have the time for this at the moment.
      • 6 months, 2 weeks ago hollaender Level 7 MOC Designer
        Thanks a lot for the instructions. I just built your version of 42009. It was challanging a bit challenging, but very entertaining. Two questions:
        The extraction of the outtriggers is very smooth, but lowering has a lot of friction and almost doesn't work (maybe due to the used batteries). Have you seen that as well?
        What is the function of the switch on the rear of the superstructure? I haven't discovered any. Maybe I made a mistake while building.
        • 6 months, 2 weeks ago Mowlwurf Level 10 Designed this MOC
          Great you built it, and thanks for the feedback.
          With my model the lowering of the outtriggers was pretty smooth until they hit the surface. Then the slipping clutch became active quite fast. Maybe you fixed some gears too tight on the axle and brought too much friction into the gearbox.
          To your second question: The switch at the rear end controls the rotation of the upper carriage. So I slightly modified the superstructure and added a few parts to the lower part. Just have a look at the area around the turntable again...
          • 6 months, 2 weeks ago hollaender Level 7 MOC Designer
            Fixed it. I changed a pin with an axle and a gear. Thanks for the quick answer.
  • 6 months, 4 weeks ago Henk61 Level 22
    Fantastic! Looks great with another color and the modifications!
  • 6 months, 4 weeks ago nkende Level 14 MOC Designer
    This is really cool! Thanks for sharing :)
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