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Bruder Manitou 2150 - RC conversion

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ddmckee54:
This is going to be a slow build.  I've got a boat-load of other projects going on, along with that 4 letter work that starts with "W" and sounds like werk.

I got the starting point of this project in the mail a couple of weeks ago, see first attachment.  I got it used off Ebay.  It's missing a few parts, but most of those parts would have been heavily modified anyway.  At $11 plus shipping I couldn't resist it.  The missing hood and door are available from Bruder as spare parts. as is the missing extendable part of the boom.  I'll probably order the door and hood, the rest of the missing parts I may try to 3D print.

I've been working on the 3D model of this thing, I'm nowhere as good as Joules, and not nearly as fast, but it's good enough to print the parts I'll need - see second attachment for 3D PDF.  I'm using Adobe Acrobat Reader DC version 2019.021.20056 to view this and it seems to work just fine for the 3D PDF.  I'm able  to manipulate the model and turn various parts on and off in the model tree.  I can see I'll need to change how I've got the components grouped together to make it a little more user-friendly in the PDF version.

I'm planning on working on the running gear first and get that operational.  The current plan is the print 3D replacement parts that are as close to the Bruder originals as possible.  I'll print the front and rear axles, the rear axle will be fixed to the lower half of the body and the front axle will pivot up and down to follow the ground contour, I think that's the way the real thing works too.  I'll keep the 4 wheel drive and 4 wheel steering as on the original.  I'm planning on using four N20 gearboxes at 100 RPM, one for each wheel.  That will give me a scaled top speed of about 16MPH, the real thing has a top speed of about 22 MPH so I'm close-ish.  The current plan is to 3D print inner rims that will allow me to adapt the N20 gearboxes to the Bruder wheels.  These motors only pull a couple hundred milli-amps at stall, so I should be able to run all 4 motors with one 10 amp brushed ESC, at least that's the plan.

One of the big problems with Bruder conversions is that they are too light in weight, being made of plastic and mostly air. I plan on adding weight to this model wherever I can, starting with the wheels.  I'm going to fill the empty space in the Bruder wheels with BB's and silicon.  I should get some added weight, and wheels that won't collapse under load.

If the "plan" turns to crap, well then I won't feel too guilty about it since I won't be out that much.  Mostly just my time, and I work cheap - when it's for myself.

Don

WeldingRod:
Looks like good fun, and a nice model!
Was it designed to be RC, or just a nice show model?

Sent from my SAMSUNG-SM-G891A using Tapatalk

WeldingRod:
Oh, you might just machine some steel doughnuts for the wheels if you want some real weight...

Sent from my SAMSUNG-SM-G891A using Tapatalk

ddmckee54:
WeldingRod:

The Bruder line of "toys" were designed to be "sort of" detailed kids toys, in 1/16 scale.  They make reasonably well detailed models and are not too fragile.  The not TOO fragile part is a necessity to be kid-safe, they are also not too expensive.  I want to build a construction fleet, but I don't want to spend mega-bucks doing it.  I've got 7 vehicles in my fleet to be converted so far, and I'm still looking for more.  I don't think I've spent more than $250 so far.

Regarding the steel donuts in the wheels, I don't have anything that size, the tires have an outer diameter of about 84mm, or about 3.3", depending on which side of the pond you are on.  I do have a 3D printer and plenty of BB's.  Silicon caulk of various colors is fairly cheap.

There won't be much traditional machining in this build, mostly it will be amputating various bits of the original model and 3D printing replacement parts.

Right now I'm tearing down the original model and making the 3D model.  An accurate 3D model will help me determine what will fit where.  It also will tell me what, if anything, needs to be removed in order for it to fit.  It also lets me design the replacement 3D printed parts at the same time.

I made some more progress on the 3D model last night, see attachment.  I did some work on the upper body and on the fenders.  I still need to split the Body components into the Upper Body and the Lower Body.  That way you'll be able to turn then off to see the inside of the model, along with the various Bits and Bob as they are added.

I got ahead of myself on the fenders, the front and rear fenders are almost the same.  I copied and pasted them into place before I should have.  As I was quitting last night I realized that I hadn't completed the design of the lower part of the fender before I duplicated them.  Now I've basically got 4 times the work to do to correct  that issue.

Don

ddmckee54:
I made some more progress on the 3D model, I fired my shop gnome and hired a shop elf.  I swear the elf looks just like the gnome did, but he gets a lot more done - Crueby swears there's a difference between the two and I believe him.  I tried firing the shop gnome last year but it didn't take, apparently all I had to do was use a bigger cannon.  With the elf's help I made what feels like significant progress on the model.  I think I've got the model tree organized a little better, using Adobe reader you can manipulate the model and turn parts on/off.  I've made a good start on the outriggers.  The outriggers pivot/drive units are identical front to back and the extendable outriggers themselves are all identical - that's why I only show one. And I'm starting to fill in the details on the upper half of the frame - it's not just a rectangular block anymore.  The new 3D PDF is attached, it's still a WIP so it'll get better.

I haven't said yet what I want to make functional by radio control on this model, here's my wish-list:
1) 4 wheel drive and 4 wheel steering with at least the front axle able to pivot to follow the ground contours.
2) Fully functional outriggers, extend/retract and raise/lower to level the unit.
3) Functional slew of the crane/telehandler body.  (I think of this thing more as a crane than a telehandler since it rotates.)
4) Raise-lower the boom.
5) Extend-retract the boom.  The real deal has 2 or 3 sections of the boom that can be extended.  I think the single movable section that Bruder has moving will be enough trouble for now.
6) Tilt the forks.
7) Working winch for the crane option.  I REAALLLY want this one since I always picture this as a crane.
8) Lights, I'd really like all the lights to be functional, but I'd settle for head and tail-lights that light up.

I got some more of the N20 gearboxes last week, up to this point everything has been theoretical with the 3D model, but I decided to print out the gearbox covers that I've got designed so far.  I found a couple of clearance issues between the covers and the gearboxes that I corrected in the model.  I don't know how I could read 4.25mm as 3.5mm, that was probably one of the measurements that the shop gnome took before he was fired.  Anyway, that's my story and I'm sticking to it.

I also printed out a test version of one of the axles and the covers for the wheel gearmotor.  I found out that I needed to put in a line-up key between the upper and lower axle halves.  I didn't have that before and when I bolted the axle halves together, they would slip around a little.  Only about 0.5mm, but it was enough to irritate me.  I also decided that I need to add a counter-bore for the bolt heads, and pockets for the nuts to press into.  I need to modify the steering arm on the wheel gearmotor covers, extending it out a bit.  All 4 wheels will steer on this model and in it's current position the steering arm will not allow enough travel before the gearmotor cover would foul the steering tie-rod.  I'll also need to print out prototypes for the other replacement parts to see how well my 3D model matches reality.

I didn't take any pictures, these are all proof of concept prints that were done with leftover partial spools of PLA that I have laying around.  At this point I still consider these printed parts as completely disposable.  Once the parts fits are verified I'll print out the parts that will actually be used.  I know I'm not lucky enough, or skilled enough, to get the design right the first try.  At least this keeps me off the streets and out of trouble at night.

Don

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