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RC models by Robert Holsting

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  Second: Suspension.

Vehicle suspension is a science, and there are many, many ways to build a suspension, depending on what type of vehicle it is for.
This will be an extremely slow and quite heavy vehicle (Top speed will be 3 km/h, weight around 40kg), so I choose the pendulum suspension.
(No springs...)

  As it can be seen here, the carrier is steered at 6 of the 8 axles, and axles are in 3 groups.
First group has 3 axles, as does the 2nd group. Last group has 2 axles.
That calls for two different pendulum suspensions; Two for 3 axles, and one for 2 axles.

  Pendulum suspensions can be bought, ready for use, but not for my wheel size.. so I had to make it all from scratch.

This is the first, very early test; a plastic mock-up of the planned 3-axle version. The long piece of wood simulates the frame to come.
This, and a 2 axle version, was then drawn in AutoDeck Inventor, and made in stiff, 3mm engraver quality brass.

  First, all was drawn in Autodeck Inventor, and a file was made for fabrication.

The original plan was to CNC-mill it in brass, but I was more than lucky, and ended up having them made in laser-cut steel at http://www.ktstaal.dk/, who comes highly recommended!

  I am SO thrilled with the outcome, and I would highly recommend laser cutting, AND steel for this.

And yes, there are two pieces too many, but rather have too many than too few... right?
Right after this, a lot of the holes were cut with M3 or M4 thread.

  Here an M4 threaded shaft has been TIG-welded to the main suspension bridges, and it's all beginning to take shape!

  Many small pieces of M3 threaded shaft, and aluminum tube, made up the support arms.

The funny tool right above the aluminum tube was used to cut the alu tube. Normally it's something your plumber uses for copper pipes.

  Early stage during assembly..

  One completed three-axle unit!
(It's the for the front.. notice the right-most axle. It has no through connection for the cardan shaft.)

  I had the suspension made in 2mm thick steel and not 3mm, because 3mm thick steel would create a clearance problem, when the steel core of the carrier are fitted later. I'll come back to that at a later stage.

  Stability is very good, even sideways!
This three axle boogie will carry around 15kg.

  This is the rear most group, and the most simple one.

  And that's it!
Now it's on with the steel core, the very spine that will carry the crane, and support every little bit.

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