Fumotec Komatsu 490 LC build

[Rakthi]

Back to the build.

As you will have noticed there is the huge hole on the bottom where the ESC for the drive motors are installed. Taking my que from the German forum I decided to do a variation on making a cover for it.

Taped a piece of paper against the hole, scanned it in and cleaned it up in Illustrator. glued paper to a metal plate and cut the holes.





Now I only have to loosen the bolts a bit and will be able to take the plate out so I have easy access to the ESCs and wiring should I ever need it. Meanwhile no muck can get in.



That leaves the wires from the ESCs to the motors. A bit of fiddling with scissors and cardboard, transferring to 0.3 messing plate, some bending and double sided tape later that is sorted too. Better would have been to have drilled and threaded a hole and attach it with a small bolt. (The double sided tape only held for 1 week )





Before installing I inserted a piece of rubber in the slot to hold the cables in. The little red arrow points to one of the 3D printed covers of the drive system. I forgot to mention earlier that one needs to cut a couple of slots to accommodate the heads of the bolts holding the gears/motor to the carrier.





Now we get to the part that worried me the most ... the hydraulics ....

First install the messing tubing on the boom and upper arm. This covers a couple of pages in the manual.

I made a template for the upper arm so both would be in about the same position. I actually should have had them closer to the bucket ... I also cut the provided small screws in half. (this was suggested on the German forum because apparently they strip easily)





As you can see not much place between those tubes.



FYI, the parts are painted. Not enough yellow to be found on this island, only non-eye-hurting paints in large supply were Matt White and Honda Grey ... Also the painting was absolutely painful with long curing times and bad reactions between the primer and paint. Sadly enough no decent spray paint to be had here in Malaysia.

Actually did come out rather nice in the end (if I say so myself)

Next I ran a drill bit through the holes in the boom and upper arm. (need a 10mm, 8mm and 4mm)



Installed the quick release to the bottom of the upper arm. (had to slightly file out the provided openings in the 2 metal bits connecting arm to hydraulic piston)



Fit with the boom very thigh so some sanding of the hinge part required. (you can see a spot of yellow there from one of the failed painting attempts)

Connecting dipper to boom.



Boom to upper wagon



Installing the hydraulic tubing was easy peasy! Cut to size, stick on nipple and tighten the metal bit with needle nose pliers.



Trying on the unpainted bodywork for fit - the counter weight that is supposed to slide over the 2 metal bars in the back didn't quite fit. The openings need some filing - more about that later.







Too finish the installation of the hydraulic lines to the valves, needed to take of the servos. I messed up drilling holes in the oil tank - needs 3 10mm holes to fit the connectors. The middle one was not right. Ended up glueing all 3 connectors with UHU Endfest glue. You can see the oil tank sitting between bucket and carriage.



View from the other side. Hook up pressure regulator etc. To get the filters in the yellow tubing, the wife's hairdryer and a bit of silicone works wonders!



Ready for oil tank



Oil tank in, and hydraulics primed according to manual. It lives - and no leaks!
Operated the valves by hand for the priming.



After that, took it out in the garden for a bit of testing. Sadly enough our back garden in that area is mostly rocky and very hard soil ...





So all my fears of the hydraulics were for naught! Got all worried for nothing.

To be continued
Cheers
Stephan

[Rakthi]

Now the modification of the counterweight.
Having seen this on a German forum, I figured I might try it too. Maybe not as professionally done, but it did work out.

Drilled a couple of holes to kind of mark out the area to be cut and loaded the Dremel with a plastic cutter.

You can also see the scratches in the primer from trying to fit it to the carriage. (the holes are not deep enough either so need drilling out)



Lots of room in there! I also bent a piece of metal to rest the battery on, and to tie the back to the front for strength.



Used Milliput for additional strength on top of the metal supports. Had made 2 extra pieces for metal for support, but they ended up not needed. (Yes looks hideous, but it works)



Slightly better looking when painted in primer



From here on it is finishing touches.

Painted in primer



Stickers applied



Windows and interior cabin installed. Towels in case of leaking oil (one never knows)





"Only" have to clean up the electronics and fine tune the settings on the RC



All the details like railings and mirrors are painted, but not installed because our cats are too interested in messing with them. Will do that once I have a storage box made.



Well that's where we are at as of today ... All in all a very satisfying model to build and just enough things to sort out to keep it interesting.

When I have time I'll see if I can get some action shots ... still have lots of training to do to get my coordination right and get the model to do what I want.

I better go looking for my soldering iron and shorten some of those wires.

Cheers!

Stephan

[calum_scania]

A very detailed and excellent build, thanks very much





I would change the layout of the hose here - having the t-piece like this and the gauge hanging of it might give you problems later on

Calum

[Rakthi]

Originally Posted by liftmys10

Cant wait to see some videos!

I will see what I can do, living here on hill on an island in Malaysia with no landline, our internet is a slow 3G connection with limited bandwidth. So video not really an option at the moment. Maybe I can do it from the free WIFI in the airport.

Originally Posted by calum_scania

A very detailed and excellent build, thanks very much

I would change the layout of the hose here - having the t-piece like this and the gauge hanging of it might give you problems later on

Calum

Thanks for pointing that out! You are right, I cut the yellow hose at the bottom of the pressure regulator too short. Will replace it when I redo the electrics. The pressure gauge is on a quick disconnect, so normally not there. But that doesn't change the fact that I have to redo those connections. Going to be messy and oily ... have to wait till the wife is out.

[Rakthi]

Had some time this morning to test out the adjusted program on the RC.

On the way out, had to park it so I could open the door. Placed it at the first convenient spot and found out the foot print of the excavator is almost the exact same size as a flat of 24 cans!





Battery is a tight fit



Got the bucket full with gravel from the parking lot (also added some by hand as layer not deep enough), seems to be holding fine like this on a flat surface.



Cheers, Stephan