Author Topic: Bruder Manitou 2150 - RC conversion  (Read 8074 times)

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #50 on: January 17, 2020, 04:36:00 PM »
Not a lot accomplished on THIS project during the past week.

My home cable modem puked on me sometime Wed. night.  The cable repair tech is scheduled for Monday, between 1 and 5PM.  This was the earliest I could get scheduled, wonder if I'll get compensated for the time that I've paid for but can't use due to their hardware failure?  (Not gonna hold my breath waiting for that to happen.)

Most of my software packages need to phone home to verify the licenses, so until that modem is replaced I'm pretty much screwed.  I hope to get the RC receiver patched into the Arduino breadboard and get some more work done on the code for the Nano - time will tell.

Don
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Offline WeldingRod

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Re: Bruder Manitou 2150 - RC conversion
« Reply #51 on: January 23, 2020, 09:59:07 AM »
Are you printing the ring gear for the turntable?  How about the bearing system?

I've used geared skewing ring bearings professionally, with a few curses due to me using them for things the manufacturer never intended;-)

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Offline WeldingRod

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Re: Bruder Manitou 2150 - RC conversion
« Reply #52 on: January 23, 2020, 09:59:38 AM »
Argh.  "Slewing" ring bearing.

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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #53 on: January 23, 2020, 01:02:53 PM »
WeldingRod:

For the gears I'm actually sorta taking the easy way out - maybe.

I ordered an assortment of 0.5 mod plastic "Robot" gears from Fleabay.  Or maybe it was Amazon - I don't remember which.  The gear assortment came in a variety of nominal bores, 2.0mm, 2.5mm and 3mm - along with a couple of pieces of 2.0mm and 2.5mm shaft stock.  I figured that a cheap injection molded gear would probably be better than anything I could print at that size.  I started with a 6VDC 100 rpm N20 gearbox and then geared that down so that I should get about 1-2 rpm out of the turret.  It's at least a 3 stage reduction, maybe  4, I can't remember - it's a Senior Moment type thing I guess.   I have the shell of the gearbox designed and I will be printing that.  The gear assortment had a couple of larger gears, 60 and 72 tooth.  I'll be using the 72 tooth gear as my final ring drive gear.  I have designed and printed the adapter parts the will allow my ring gear to mate up with the modified Bruder turret.  This all gets bolted together with M3 button-head bolts - courtesy of my 3D printer repair/modification parts.  The model originally had a gear drive steering mechanism that ran down through the turret pivot.  I was going to try to use it for the ring gear, but it was just too big.  Those gears did wind up in the "I can use this someday" box though.

The ring bearing, well that's kinda the same answer.

This model is made out of nice slippery plastic.  It's not styrene since it's not brittle, and I don't think it's ABS since it is somewhat resistant to acetone.  (Had to repair a  boo-boo with the X-Acto knife while dis-assembling the model.)  The model was designed to be turned by a kid - A LOT, and I figured that I'm not going to be slewing it THAT much.  Initially I'm just going to use the model's ring bearing as designed by Bruder.  If it starts to wear too much, of if there's too much friction for my homebrew gearbox to overcome, then  I'll have to come up with a proper ring bearing.  One that will work with my ring gear and still accommodate the slip-ring assembly.  The slip-ring assembly is about 13-14mm in diameter and its' got 12 circuits that are good for 250mA each. 

I'll try to remember to post an update of the 3D PDF either tonight when I get home, or tomorrow.

Don
« Last Edit: January 23, 2020, 01:41:27 PM by ddmckee54 »
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Offline WeldingRod

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Re: Bruder Manitou 2150 - RC conversion
« Reply #54 on: January 23, 2020, 10:38:51 PM »
Yeah, gears that small would be a major printing challenge!
Keep us posted!

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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #55 on: January 24, 2020, 11:37:44 AM »
Attached is the 3D PDF as it currently sits.  If you can open it, you can manipulate the viewing angle.  You can also turn bits and pieces of the PDF ON or OFF.

I haven't 3D modeled the entire Bruder model, just the parts that I've been working on.  I don't model any parts until I need to, makes working with the 3D CAD a little faster.

So far what I've been working on amounts to designing the following modifications:
1) The upper and lower frame halves.  Including determining what had to be amputated to fit the new axles, AND still be able to put the frames back together.  I'm trying to keep as much of the internal structure of the Bruder model as possible.  I don't want to compromise the strength of the model any more than I have to.
2) The front and rear axles.  I replaced the existing axles because the Bruder "suspension" was nothing more than allowing all the spindles to float up and down about 5mm.  My version has the rear axle fixed to the lower frame while the front axle can pivot about 5-10° up and down.  I will still be a rough ride, but it should keep all 4 wheels planted on the ground - MOST of the time.
3) I replaced the steering, the original Bruder steering had WAY too much slop in it.  It had to have slop in it due to their suspension.  Now the model should go the direction I want it to go, not just sort of in that direction.
4) I designed the axles around the N20 gearmotor, and modified original Bruder wheels.  This model will have 4WD from 4 wheel-motors, just like the real deal.
5) I found a home for an 8 channel RC receiver, that goes where the model's "engine" would be.  I can run the model on 6 channels, but I designed the changes around an 8 channel receiver.
6) I've designed the servo controlled 5 position switch and its' mounting bracket.  Although when I look at the PDF I see that I still need to find a permanent home for a pair of them.  I believe that I had planned on putting them in the upper frame, in the open bays next to where the outriggers mount.
7) I've got the slewing system designed, that required modeling part of the turret.  The slewing gearbox is the blue object sticking out the side of the model.  The area that it protrudes through, and into, is actually the "fuel tank" on the model.

Still to go, but probably all based on N20 gearmotors:
Boom lift mechanism - an N20 gearmotor with probably a 5mm or 8mm 3D printer lead-screw.
Boom extension mechanism - ditto on the gearmotor/lead-screw.
Fork tilt mechanism - ditto on the gearmotor/lead-screw.
Winch mechanism - don't know, maybe start with one of the 3D printing pen worm drive gearboxes used for filament feed?

That's enough Yakking for now,
Don
Too many irons, not enough fire.

Offline Will_D

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Re: Bruder Manitou 2150 - RC conversion
« Reply #56 on: January 25, 2020, 04:36:56 AM »
Really looking forward to the video at the end of this. Amazing level of detail and info in all your posts.

Always wanted to make a large Groves-Cole mobile crane in Meccano. It was the biggest at the time 450T lift, and about 8 axles. Scale was based on the largest roller ring bearing you could builds out of (iirc) the 6" ring girders and blue circular plates.

That was built and I still have it some where and also a bag of suitable tires. That's as far as i got
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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #57 on: February 19, 2020, 05:45:02 PM »
No progress on the project in the last month.  I've been buried with the demands of the day job, we're going to be tearing out 2 existing production lines and installing 2 new lines.  The next couple of weeks don't look any better - actually worse.  I try not to bring the work home with me, but for the last week I haven't had a choice.  I already know what I'll be doing THIS weekend, and relaxing is not an option.  Once we get the electricians and systems integrators cut loose on this project the hardest part for me is over, then all I've got to do is ride herd on them so THEY stick to the schedule.

I'll get back to this project when I'm not so completely fried from work that all I want to do is sit down and veg-out.

Don
Too many irons, not enough fire.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #58 on: March 05, 2020, 03:59:55 PM »
OK, update time.  For the first time in probably months I printed out a test part for the Manitou.  I printed the right front fender when viewed from the front of the machine, and guess what?  It took about 2 hours to print and it didn't fit!  One of the locating tabs was off by about 1mm - maybe a little more.

Not only did the fender not fit, the bridging layer screwed up.  For some reason the bridging filaments were parallel to the support filaments, so in between the supports they was able to twist in the breeze.  Every couple of mm the air from the cooling fan would twist that layer and it would cool twisted up.  It took about 3-4 layers of mostly crappy adhesion before the layers settled down and printed correctly.  That part of the fender is only about 5-8 layers thick.

I also found out that I need to modify the openings for the headlights and turn signals.  I might have been able to install the LED's in the current configuration, but it would have been a struggle.  Since I copied the light buckets onto the rear fenders, they also need to be modified.

I think I found the parameter in the slicing software that allows me to rotate the angle of the supports.  They were at 0°, I'm going to try rotating them 45°.  Just one more detail to pay attention to when slicing a part.  I'm going to make the changes to the part and print it out again tonight.  I'll take a picture or two of the new and improved fender, and see if I can get any decent pictures of the funkiness caused by the bridging layer twisting in the wind.

Don
Too many irons, not enough fire.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #59 on: March 06, 2020, 01:31:14 PM »
No pictures yet -  I rotated the supports but it didn't help.  When the printer got to the bridging layer, it did the same thing.  My current theory is that this is due to the fact I have the slicing program configured to give me a layer of separation between the supports and the bridging layer.  This makes it MUCH easier to remove the supports.

So.... About 9:30 last night I changed the vertical upper separation to 0 layers and was going to reprint the part.  I knew it took a little over 2 hours to print the part so I planned on just starting the print then going to bed and letting the print finish. 

I've said before that my printer is in my living room, but I haven't said that I use the sneaker-shuffle to transfer files from my work-horse PC to the printer.  I don't want to tie-up/bog-down that PC by printing from the PC via USB, so I print from files on a micro SD card.  Apparently I actually DO shuffle, because last night I noticed I was getting a shock after I walked across the room.  I don't get a shock when wearing my work boots, just my moccasins.  I try to touch a part of the grounded frame so that I don't ZAPP the electronics but Murphy reared his ugly head. 

Apparently I forgot to ground myself on the frame, because when I went to plug in the SD card I felt a shock through the fingers holding the card.  At the same time my screen on my printer went black.  I said "Oh Fudge", or something like that, and cycled power to the printer hoping it was only a temporary thing and the screen would come back to life after a re-boot.  Yeah... Not so much. 

I tried the shut the power of for 15 seconds then turn it back on trick,  I tried the shut the power of for 30 seconds then turn it back on trick - neither worked.  By this time I had pretty much cycled completely through all the expletives that I've learned in the last 65+ years.  So I went to bed thinking I'd try it again in the morning, and if that doesn't work then I'm going to need to order the proprietary control boards.  When I powered up the printer this morning the screen obligingly came to life.  I haven't tried printing yet so I'm still not sure if I actually dodged the bullet or not.

Yeah I know, I SHOULD be wearing a grounding strap.  When I'm handling IC's or other static sensitive electronic parts I do, didn't think I needed one just to walk across the room.  Tonight I think I'll try printing with my boots on instead of my moccasins - see if that helps.

Don
Too many irons, not enough fire.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #60 on: March 09, 2020, 03:48:19 PM »
Well it's official, I killed the printer.  When I fired it up Friday night it booted up normally, the screen came to life and was on the proper screen for having completed its' boot up.  What I didn't have was a cursor, or any way of controlling the printer.

I started tearing the printer down to get to the electronics and found out that like most 3D printers that use the flavor of the RAMPS board, this printer also the electronics divided into 2 sections, the control board and the motherboard.  This printer is a Monoprice which is a rebadged Wanhao D6 by the way, but more on that later.  However unlike the vast majority of printers, Wanhao uses proprietary boards.  What they call the control board contains the SD card hardware, the LCD screen hardware and the control knob/button hardware.  I think this is probably the board that I ZAPPED since the SD card plugs into it.  I was trying to find a supplier on this side of the pond that had a control board, no such luck.  The one place that did list it was out of stock.

The Wanhao D6 motherboard, where to start?  This thing is flippin' expensive, I found one on Ebay for $185 USD, the Wanhao 3D printer parts site wanted about $250 USD. I also found that this board has a built in flaw, a 2 buck relay that controls the 24VDC to the printer.  That relay's contacts are rated at 10A for 30VDC, when both heaters are on at the same time the load is 12.5 amps - just for the heaters.  These relays are known to fail, but they do warn you they are failing, they display one of several different error messages.  I would periodically get a heater failure message that would require me to reboot the printer - this message was on the list of error messages caused by the failing relay.

Aliexpress was the ONLY place I could find both the control board and the motherboard.  the cost was about 1/2 to 2/3 of the cost anywhere else, but I won't see my parts until 3/31 with UPS Expedited shipping.  I could have paid twice as much for DHL shipping, but it only saved me 2 days so it wasn't worth it.

So bottom line, I've definitely got a busted control board, and I've got a motherboard that's most likely failing.  With repair parts 3+ weeks away, in order to keep from going into 3D printing withdrawal, I fired up the old printer which has been sitting and gathering dust since I got the Monoprice - almost 2 years now.  Other than having to re-level the bed, not uncommon with that printer, it took right off with no problems.

I printed out the front fenders using the Prusa Clone, and after a couple of modifications and reprints they actually looked pretty good and fit in their desired location.  Ummmm… yeah, make that they fit - not so much.  The fit problem showed up when I put the turret on the frame and swung it around to check clearances.  It didn't quite clear, the turret would interfere with the top of the fenders.  One more re-design to lower the fenders by 2mm and I should be good to go.

What lies ahead for the D6 clone - not sure.  I'd like to get rid of the expensive proprietary boards but with the way the control board is laid out, in particular the slot location for the SD card, I don't think that's likely to happen.  I found a version of Marlin on GitHub that's specifically for the Wanhao D6 motherboard, I think that is definitely in the future for the D6. (I got used to Marlin on my Prusa clone.)   I never did like Wanhao's proprietary menus, and their info screen leaves a lot to be desired.  Small things, like useful information.  The Wanhao info screen basically is just an estimated time to print completion - in hours at first, then minutes when the remaining time is under an hour.  If I keep the proprietary motherboard I will still have to deal with the relay problem, but there's plenty of room in the base of the printer to wire in a remotely mounted 5VDC relay with contacts that are actually rated for the real load.

Don
Too many irons, not enough fire.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #61 on: March 11, 2020, 03:52:20 PM »
I re-designed the LF fender, only one I've got re-designed so far.  If you're familiar with the terms chopping and channeling, I channeled the fender by 2mm.

I also decided to scrap the software generated supports and put in some sacrificial supports only where needed, I did this for 2 reasons.  First reason, I wasn't happy with the finish on the bottom of the part.  I know it's only the bottom of the fenders, but I"LL always know the problem is there.  Second reason, by only putting the support where it's needed I cut the print time almost in half.  The print time went from 163 minutes down to 83 minutes.  Since it takes about half as much time to print, I'm guessing that I'm probably using about half as much filament with my supports as opposed to the software supports.

I'm hoping to get the RF fender and supports designed and printed tonight.

Don
Too many irons, not enough fire.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #62 on: March 12, 2020, 02:06:48 PM »
I got the RF fender redesigned and printed last night, I think I've got a pair of keepers.

Just for funsies I weighed the fender I could find with the software generated supports, it weighed 13g.  The fender I found wasn't complete yet so I'm guessing that it probably would weigh in at around 14g complete.  I also weighed the part printed with my supports, after the supports had been removed and it weighed 7g.  So in addition to taking an extra hour to print, the software generated supports generated about 50% waste with every part printed.  I'll have to weigh one of mine with the supports still attached to see how much waste I have.

By next Monday I should have all 4 of the fenders printed in their final version.  If I don't get any pictures before then I WILL take before and after pictures with the original fenders, all 3 of them, and all 4 of my final printed fenders.

Don
Too many irons, not enough fire.

Offline russ57

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Re: Bruder Manitou 2150 - RC conversion
« Reply #63 on: March 13, 2020, 07:49:45 PM »
For the sd slot issue, I understand you can get 'extension' cables so you could locate the slot where convenient and plug the cable to wherever the replacement m/b is.
Then print a nice little bracket for it...

-Russ


Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #64 on: May 14, 2020, 02:18:32 PM »
I've got my Wanhao D6 clone 3D printer running again.  I didn't need to replace the motherboard, just the input board.  I did want to find out if I fried the original motherboard when I static-zapped the input board - I did not.  Since it's still the original motherboard I occasionally get a fatal heater error due to the failing relay.  However I DO have enough replacement relays for the motherboard, that are PROPERLY rated, to last me well into the next decade.

I'm printing out parts for the Manitou again, I've got the front and rear axle parts printed, along with most of the wheel motor parts, and the parts needed to install the axles.  Last night I started printing the parts required to modify the original Bruder wheels.  I'll take some pictures when I've got this thing sitting on its' own wheels again.  Until then it's just parts, and like the old commercial said - "Parts is parts".

Don
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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #65 on: May 15, 2020, 12:14:03 PM »
OK, I need to hear some opinions - from someone other than the voices in my head.

I has originally planned to fill the hollow portion of the original Bruder wheels with a BB/silicon seal mixture that would have been basically troweled into the hollow wheel.  The Bruder wheels have about half of the sidewall cut away on the back of the wheel.  The BB mixture would have been troweled into what's left on the inside.

Me and the voices are starting to think that's a bad idea for a couple of reasons:
1 - It would probably stiffen up the tire sidewalls too much.  You want to have some give in the tire sidewall because every tire has some degree of "squat" to it.  A BB/silicon mixture wouldn't flex that much.
2 - Troweling that mixture onto the inside of an existing wheel opening would be messy at best.
3 - I did some off the cuff calculations and depending on how well the BB's packed together, an estimated 50-75% fill, the common copper coated steel BB would add between 1-1.5 pounds per wheel.  I'm using the same gearmotor that RCMODDER used in his CAT Telehandler conversion.  They might NOT handle the extra load, 4-6 extra pounds could be overkill.

Plan B is to redesign my 3D printed rim.  I think I can remove a good chunk of that part and still keep a 2-3mm wall thickness everywhere.  I'm estimating that a cylinder with a 60mm OD, a 50MM ID, and a height of 15mm could be removed.  This should give me a usable volume for the BB mixture of about 130cc or roughly 8 cubic inches - IF I did my arithmetic right.  Using my 50-75% fill guestimate, I should get an additional weight of an estimated 0.5-0.75 pounds per wheel.  Plus, since the inner rim still has to fit in the available sidewall opening, I could 3D print mold parts to ensure the inner rim would fit in the wheel opening.   

Do I hear any Plan C's?

Don
Too many irons, not enough fire.

Offline russ57

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Re: Bruder Manitou 2150 - RC conversion
« Reply #66 on: May 15, 2020, 07:11:04 PM »
Think I need pictures of the wheels.
 But what about a polyurethane foam as filler?


-Russ


Offline WeldingRod

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Re: Bruder Manitou 2150 - RC conversion
« Reply #67 on: May 15, 2020, 09:36:15 PM »
I would load test the wheels to see what you think of the loaded shape!
You could glue short bars into the tires with space between them to get weight with less change in stiffness.
If you can find/make small foam pellets you could make your bb/silicone more flexible.  A close packed bb/rubber thing will be very stiff.  Adding compressible stuff to the mix will help that.  A monolayer of BBs glued in would be less stiff but still rim weighted. 
A loose steel doughnut in the tire with clearance equal to the squish you want might be an improvement.  It would allow squish but still keep the tire on the ground AND be dense.  Do you have a lathe?  Cast lead or solder doughnuts are another possibility...
You might mould one to roughly the right shape and test its flexibility!
Hub weight makes sense!
RC truck folks use foam doughnuts in the tires to adjust stiffness.

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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #68 on: May 20, 2020, 03:37:19 PM »
I've been working on the design for the attached garage that I want to have built this summer, so I haven't got a lot done on this project lately.

What work I have done, has made me revise my original estimate of the inner rim volume available where I can add weight downward - a lot.  Instead of a tube with an OD of 60mm, that's 15mm tall, with a 10mm wall thickness - the wall is only 5mm thick.  I may actually need to find another spot to add weight to the tires.

The room inside the model is kinda' limited and I don't want to waste any of it on dead weight.  I might be able to add some weight in the upper body, but I'm building this thing from the ground up so I want to keep all the interior volume open in case I need to jam something in there.  You know, the unnecessary stuff like batteries, receivers, servos, light controllers... that kind of stuff.

I'll try to remember to get a couple of cross sections from my 3D model of the wheel.  Pictures don't turn out that well.  Since I'm printing most of the wheel parts in black filament, there's not a lot of color contrast between the Bruder wheel/tire and the parts I've printed.  Which I guess is really a good thing.  The last time I worked on this project I had found a spot where I might be able to add additional weight without affecting the sidewall stiffness.

Don
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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #69 on: June 23, 2020, 04:58:44 PM »
A disappointing update.

A couple of weeks ago I went into Cabela's to look at some shotgun shell reloading supplies, I wanted to check into getting some lead shot to use for wheel weight instead of BB's.  Cabela's is a large chain of stores supplying hunting/fishing goods - for those not on this side of the pond.

I was talking to the nice man at the counter and we got to looking at what size shot was available, and what they had in stock.  I wanted something smaller than an ordinary BB.  A BB has a 0.177 caliber so there would be a lot of air between the BB's.  That's what got me to thinking about shotgun shell reloading supplies.  The smallest shot that Cabela's had in stock was 25 pound bags of #6 shot, way too much in both quantity and physical size.  25 pounds would probably be a 2 or 3 lifetime supply for what I want to do, and #6 shot wasn't THAT much smaller than a BB.  Plus I didn't want to spend $50 just to find out it wouldn't work.  We determined that #12 shot would be just the ticket, if I could find it because Cabela's didn't stock it - anywhere.  #12 shot is a maximum of 1.3mm in diameter and is used for "snake loads".  The round will blow the hell out of a snake at a few meters, but not do much damage to anything over 10 meters away.  I went on-line to the only reloading supplier that had #12 shot and ordered an 11 pound bag.  Surprise-surprise, with shipping it STILL cost me about $50.

Anyway, I printed up some containers that fit in some of the unused volume within the wheel.  Even with the small volume that I initially printed I'm getting an additional 85-90g per wheel, and I can make the containers a lot bigger.

Last weekend I got the brilliant idea to bury the motor leads within the axles that I printed.  So I spent Friday night and Saturday morning redesigning the axles to hide the motor leads, I had some other improvements that I wanted to make to the axles anyway.  I even redesigned the gearmotor housing to cover and route the motor leads - it was BRILLIANT!  Then that little voice in the back of my head made itself and its' question heard.  "Does this clear the frame of the crane?"  AWWWW CRAPPP!!!!  IT DON"T FIT!!  The motor leads are entering the axle within the frame where's there's absolutely NO clearance.  Not only that , but the gearmotors JUST clear the frame.  That's just the gearmotors, NOT the gearmotors AND their wires.  Not enough clearance, maybe a mm.  And the ribbon cable is 1mm x 2mm, 1-2mm more clearance and I'd be happy.

My Brilliant Idea turned out to be a Brain Fart.  I wound up throwing away 90% of 2 days work.  Plus I now know that I've got to redesign the back of the gearmotors, and this time ALLOW for the wires coming off the back of the motor when I check clearances.  (Remember to CHECK the clearance to the frame too ya dummy!)  I really am getting closer to putting this thing back on its' wheels - at least that's what I keep telling myself.

It's always the simple things that bite you in the butt.
Don
Too many irons, not enough fire.

Offline David Jupp

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Re: Bruder Manitou 2150 - RC conversion
« Reply #70 on: June 25, 2020, 06:44:06 AM »
It might not be worth too much effort chasing a particular size of shot.  The reason being that for a particular regular shape, the absolute size of the particle does not change the bulk (packing) density achieved - as long as the container is reasonably large compared to the particles.

To get a higher bulk density you need a distribution of sizes - so the smaller particles can occupy some of the gaps between larger ones.

Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #71 on: June 25, 2020, 05:36:17 PM »
David:

I went with the #12 shot, 1.3mm diameter, because that allowed me to print a container and add about 25-30g of extra weight into a space where I couldn't even fit a #6 shot or a BB.  Which are about 2.8mm and 4.5mm in diameter respectively.

I carved a chunk out of my 3D printed part that fills the gaping 62mm hole Bruder left in the back-side of the tire.  I then hollowed that part out to the thinnest wall I was comfortable printing.  I've got my filament width fixed at 0.3mm.  I'm a bit ham-handed at times so I set the wall thickness at 0.6mm.  This left me with a container with an OD of 61mm, walls 0.6mm thick and about 15-20mm deep.  The rest of the wheel support structure has about a 3mm wall thickness, I know that's over-kill but so what.

If I can remember to do it, I'll try and set up an exploded view of the internal 3D printed parts for the tire.  Designspark 3D is not real friendly for exporting partial views of a model, let alone an exploded view.(It just plain doesn't do it!  When I try exporting a 3D PDF with parts of the model hidden, it exports the ENTIRE model.)  But at least I can wrap my head around it and make it work, Fusion 360 is just too frustrating for me at this point.  Maybe after I retire in a few years I'll be able to spend a week or two doing nothing but Fusion 360, then it might be less frustrating.

Don
Too many irons, not enough fire.

Offline awemawson

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Re: Bruder Manitou 2150 - RC conversion
« Reply #72 on: June 26, 2020, 02:20:43 AM »
Get your view on screen and ‘screen grab’ - control / print screen in windows - then paste it into Paint or whatever, trim, resize, save as a file.
Andrew Mawson
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Offline ddmckee54

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Re: Bruder Manitou 2150 - RC conversion
« Reply #73 on: June 26, 2020, 11:29:18 PM »
Andrew:

Thanks, I've used that trick before.

OK, before I forget about it - AGAIN....  I've attached several files, the first is the 3D PDF of the revised wheel, for those of you that can open it and actually see something. 

The second file is a cross section shown through the centerline of the wheel.  The silver/grey part with the purple cross section is the only part in this view that isn't 3D printed.  This is the rim of the Bruder wheel.  The Bruder rim and tire are one piece.  I believe that the rim is molded first and then the tire is molded over the rim.  Probably using an over-molding method similar to the way hand grips are molded on some tools.

The third file shows the weight containers and the inner part of the tire, with the containers oriented so that you can see the openings.  It took 4 design iterations of my inner tire before I got the Bruder tire to stretch over my 3D printed inner tire and then snap back into shape with a relatively smooth transition in all directions.  With a flexible tire and a 62mm diameter opening you'd think it wouldn't make much of a difference, but you'd be amazed the difference 0.5mm in diameter can make.  For reference in this view I have also shown 3 different sized spheres.  NO, they are NOT beryllium spheres - these are smooth not dimpled.  The smallest is the 1.3mm diameter of the #12 shot.  The mid-sized sphere is the 2.8mm diameter of #6 shot.  And the largest sphere is the 4.5mm diameter of the BB.
Too many irons, not enough fire.

Offline WeldingRod

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Re: Bruder Manitou 2150 - RC conversion
« Reply #74 on: June 27, 2020, 12:52:36 PM »
On maximizing the density, you want what's called an apollonian sphere packing.  Look for a dense object that is 0.29 times the shot diameter.  Sand, maybe?
A three level packing with just a touch of water will turn into a fluid.  Very weird to convert stiff mud into free flowing slurry by ADDING super fine sand...  we used to.give our clients kits to try this out; it simulated one of our oilfield cements.

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