Another RC model side project

[crueby]

Splendid 

I will enjoy following this one along and also need to look at the magonhrc website.

Here is their site:  https://magomhrc.com/en/
The menu in the upper left corner will get you to all the catagories, including the parts for each model. Lots of fun stuff. Step one, win the lottery. Step two, order some of everything!   

[crueby]

Time to test the electronics for the chassis on my RB-19. This test was to check out the radio and speed controls for 5 of the 7 channels used in the final model. Still need to add the boom tilt servo/gears, and the servo for the bucket door opening. I made a little plexiglass platform for the electronics to sit on in the front/left corner, and have rough cut out the larger aluminum plate that will be the cab floor. In the video that large plate has a paper template taped to it to assist in drilling the holes to attach it to the existing holes in the chassis top plate.
All seems to be working quite well. The radio I have allows me to tune the servo endpoints/speeds, so I was able to cut the speed of the cab rotating by about 60%, at full speed it was fast enough to make the operator fall out of his seat! The track speeds seem reasonable, can reduce them if need be. So far so good! Buying the chassis was a huge time saver, still leaves fabricating the booms/bucket, and the cab shell will be 3D printed.
Here is the video:
<a href="https://www.youtube.com/watch?v=mLGJmbhguNk" target="_blank">http://www.youtube.com/watch?v=mLGJmbhguNk</a>

[Kim]

Very cool! 

Looking forward to seeing this one come together!
Kim

[cnr6400]

  Great looking chassis Chris! No shop elves hanging off though - are they locked in the brig again? 

[crueby]

Great looking chassis Chris! No shop elves hanging off though - are they locked in the brig again? 

They kidnapped a Keebler elf and are in the kitchen learning new cookie recipes...

[cnr6400]

another Keebler elf?  (didn't they pay out $1.20 and a bag of stale cookies ransom  the last time?)

[crueby]

another Keebler elf?  (didn't they pay out $1.20 and a bag of stale cookies ransom  the last time?)

Those Keebler elves are always singing all night, really nasty after a few drinks. I had to pay to send him back!   

[derekwarner]

Those three geared motor rope drums have me wondering Chris  ....do each have a threadform machined into the major OD....so to ensure pay-out and pay-in of the wire ropes do not become tangled or out of sync?

I glanced  thru the 2 hundred something items in the Magom WEB site catalogue, and whilst many are very expensive, the majority appear realistic in their pricing considering the functionality provided

The tracks and drive sprockets appear as an example of cost-effectiveness

Derek

[crueby]

Hi Derek,


Yes, the drums do have a coarse thread type groove in them to guide the cables along the length. The end plates have holes to hold the cable ends as well.

[bent]

WOW, what a cool project!   

[Roger B]

 

As Derek says, the tracks may seem expensive until you think about machining each link 

[crueby]

As Derek says, the tracks may seem expensive until you think about machining each link 

Definitely!  It would have taken a long time and a lot of material to make it myself, and would not have the details that they CNC into them. I'm impressed with it.

[crueby]

While waiting for less stormy weather to get parts for the Kearsarge engine outside to silver solder them, the shop eleves and I are back in the shop playing on the Ruston shovel build. The floor plate for the cab has been finished off, lots and lots of holes drilled/tapped for all the machinery, plus added a plate at the front end of the cab to take it out to finished size, making the spot to mount the pivot brackets at the base of the boom. In the center foreground is the sail winch servo and worm gear box that will hold a long arm for the boom tilting cable. The RB-19 could be configured a number of different ways, with shovel booms, a crane boom, a pile driver, and a drag line, all using the same machinery. For the shovel version I am making, the boom could be tilted in a range of 20 degrees, to allow it to either reach higher on ditches or lower into trenches. So, I dont need as much travel on that cable as on the others. The black uprights at the lower left are the supports for the limit switch mechanisms (still to be made), and you can just see the end of one of the large gearmotor shafts behind them, where the cable drums will go.


There is still the gantry framework that will sit above all the motors/etc, which will hold the pulleys for the cables out to the booms, as well as those limit/drum parts, but I've decided to jump forward to the main boom construction. It has a 18.75" distance from centers of the bottom pivot to the outer pulleys, and will be made from some 1/8" thick stainless flat bar. Started with the side panels, drilling the axle holes and the rows of holes down the edges to hold the frames for the top/bottom panels. The boom tapers from the center down to the ends, so the panels will be made in two sections. The booms will also taper from side to side from the base to the end, so lots of profile milling to come. For now, am leaving the side panels with parallel sides to make it easier to hold in the vise.
First the holes were all drilled, tap size, then I started clamping the frame pieces on one by one to drill them. Starting with the same tap size drill, using the side plates as drill guides. Then each frame section is unclamped to drill them out to the clearance size.


Here is the first frame section assembled with SHCS from the inside, the ends of the screws going flush on the outside.

One down, seven lengths to go. As mentioned, the sides taper in from the base to the upper end. Since that angles the axle holes, they have been drilled a little undersized for now. The ends of the plates will be bent so the ends are parallel to each other, or as close as I can get them. Thats why I drilled undersized for now, will take them out to final size after everything is assembled. There will be bronze bushings in all the holes.

The dipper stick (the moving boom holding the bucket) is a one piece square bar, 5/8" across. That will slide in a fancy bearing assembly that pivots on the middle axle, moved by cables. That will be an interesting mechanism!

[Kim]

Nice progress on the Ruston! 

And way to make good use of that bad weather time till you can get out to do the silver soldering

Kim

[Roger B]

That's looking pretty complex, a fun machine