1/25 6 Axle Lattice Crane

[Southgate]

This is my reason for joining this forum, this 1/24 crane. I wish I knew about you guys when I started on this, probably could have saved me a lot of trouble. BUT, Despite my prior lack of RC experience, the crane is fully operational as far as I want it to be. Still this is very much a WIP, a lot of work yet to do on almost every feature of the crane.

With a 3 channel RC setup, the carrier drives at a nice slow speed, and all 6 front wheels steer.There is a motor-gearhead in each of the rear hubs rather than using differentials. The separate motors-setup has no problem with differentiating, it can do tight turns without pushing or dragging any of the drivers. The 3rd channel operates a separate feature I'll go into later if anyone's interested.

The upper unit is fully RC functional too; slewing,(rotation) boom lift and drum are controlled by a 4 channel airplane radio. Slewing requires 2 channels: on for direction, one for speed. I tried to use a reversable ESC but this little motor wouldn't have it, so I devised another way to control it.

You just can't get a close up overall picture of a crane!




Here are some features. I'l try to cut the blah-blah and let the pix do the talking mostly.

The boom, live mast and gantry all lay down realistically for transportation mode, and they pull up and lay down hands-off, except to guide the pendants out of their own way when laying it down. Even a real crane requires hands on for this.




In fact the model is "self erecting", it does all the lifting of any components needed for operation. again hands on are required only where this is needed on the real machines.

I'm not going to make a habit of driving it in the dirt, but I wanted to see the front and rear wheel equalization working...


You can see that in the extreme here.


Made of aluminum, steel and brass, she tips the scales at about 29 lbs. The cosmetic bodywork will be plastics, mostly.

3 steer axles:




Pretty early on I was forced to the conclusion that building a crane would require a lathe and mill. I managed the funds (sold a truck) and got a Sherline 4400 lathe and a model 2000 vertical mill.




Now I can make some parts!

There are lots of other picturs, I'd be glad to share, but I need to go run an errand, so I'll be back. Thanks for looking Dan.

[SmallHaul]

Welcome Dan, that is one incredible crane! Nice work.

I have a sherline as well and it is fun to use.

Where did you get the tires? Can you take a picture of it with a soda can next to it for size reference?

[9W Monighan]

Welcome to the board. I'm sure one of us can help out in any way with all of our own individual areas of expertise. I have a friend in MD. who I need to have post here, that's building a 1/25th scale LIEBHERR LR1400 crawler crane out of brass. I'm helping him with the gearing and larger machine work since his Sherline machinery is too small for some parts. Seems like from our older GT board when somebody had trouble with a build we all put our two cents worth in and came up with a cure.

[Southgate]

Thanks, Guys! Scott, the tires came from AMT IH Payhaulers. I'll get some size reference pictures on here later, 9W. Please, do whatever it takes to get your friend to post and share his crane!

Here's kind of a size ref shot. That's a 1/25 dodge van based service truck next to it here.


This is an older picture. The frame has been shortened about 2 inches between the wheel bases since this pic was taken, and that black box containing batteries and controls has been shortened too.

[SonoranWraith]

That build looks great. Nice work on making the parts. Styrene skills to be seen soon!

[ddc333]

Most impressive you have some amazing skills there

[JAMMER]

Southgate you are doing a very nice job keep it up. Ed

[Cossett]

Hi Southgate,

Welcome to this forum,

Been watching you build this over on The Truckstop forum and I'm glade you brought your crane over here cause it's a beast & making it in 1/25 takes some talent

Cheers Cossett

[Espeefan]

Southgate, this is incredible! I have never seen anything like this before. Words do not describe how amazing this build is. This definitely ranks up there as being one of the coolest builds I ever seen. I'm surprised you decided to settle for 1/25 scale, but I imagine anything larger would require you to keep in a garage of it's own, and then you would only be able to play with it outside! For 1/25 scale, the detail is awesome. Love the suspension and the three steering axles! The crane's inner workings are something to see as well. Very cool! Thanks for sharing, and good luck, as the project continues. I'm looking forward to the updates.

[Southgate]

Thanks for the responses!
Cossett, I joined this forum as a result ot the invite you posted at...was it the truck stop or commercial? Anyway thanks for the link!

As far as my skills go, I think it's been more an issue of determination. I don't like soldering, for one thing. I learned what I know about machining on this project, and that has been a blast so far. With a ton of trial and error, this thing has changed so many times i could almost assemble all the original pieces into it's former self! Plus, it started out as a stationary carrier with a cable tethered power pack for the upper, that all went bye-bye, and the learning curve started all over. RC had some hidden challenges.

Styrene is my comfort zone, but I usually give this project the summer off, and this is it's 3rd or 4th. So the body work is waiting, and I'm thinking about designs on that. Lotsa ways it could go.

1/24- 1/25 is my scale of choice for everything other than HO. You'll probably notice that the crane is usually perched on an unfinished HO model railroad. Anyway, the crane will have it's own fleet of tractor trailers in the same paint scheme. Building it in 1/25 has proven harder than I thought, space is at an extreme premium in both the carrier and the upper unit. There is even a battery in the carrier's fuel tank to help save space. The frame is loaded with either mechanisms (more on that soon), or batteries. There is room in the upper unit for one more drum (winch) but it would require another channel. I may use another 2 channel radio to operate it later on.

The crane is freelanced, but follows closely real crane designs, fairly on the modern side. I couldn't find complete enough drawings or a prototype that sits still long enough to pattern after, and I got tired of looking and waiting, or finding one that could be mechanized using the available motors and such.

One of the mechanisms in the carrier's frame is this lifting unit that lifts the stack of counterweights onto or off of the upper unit's deck.


A real crane stacks it's counterweights on the deck with either a short boom, or a special setup boom. Then when it has them stacked on, it rotates 180, and hydraulics in the carrier lowers the set onto some kind of hooks or platform on the upper. This was a pain, but when I saw a real crane do this, I HAD to have it on mine!

The idea is that the little "cart" rides in a set of ramps. The card is held in it's relative position on the frame by a tie rod. The ramps push or pull under it, raising or lowering it as need be. The ramps are driven to and fro by a long threaded rod with a motor-gearhead. (that 3rd channel on the radio is a shift control) This doesn't have or need speed control, just a servo that kicks a DPDT switch, and then limiting switches at either end of the throw with diode bypasses for change of direction (polarity). It works like a champ, has no trouble lifting the 8 lbs of counterweights.







Counterweights here are on the carriers lift unit. I have machined out more clearance room since thia picture was taken off the underside of the deck

Weights now on the upper unit. It look like a gap between the deck and weights, but there were spacers in there. That has been improved a bit too. Operational for about 2 years or so, I still get a kick out of watching this whole process work!


As on a real crane, the gantry can not fold down with the weights in place for transport, but the crane can move around, and can even carry a load as long as the carrier and upper are in alignment, with the counterweights facing forward, the load behind.

I mentioned motors earlier. I have some sources I can link you to if anyone is interested in these gearhead motors for other mechanized purposes. I could very easily see an operating 1/16 wrecker unit using these guys. (I'm not gonna get into another scale myself...huh-uh)

Still more later if anyone is following...Dan

[ihbuilder]

Dan , that thing is a master piece . I 'll be needing gear heads for my rotator . I got a few sites I'm looking at but a few more would be a help .


IHSteve

[Southgate]

Originally Posted by ihbuilder

Dan , that thing is a master piece . I 'll be needing gear heads for my rotator . I got a few sites I'm looking at but a few more would be a help .


IHSteve

Thank you, Steve. Here's a link to a motor that is close, if not identical to the ones I used the most on my crane for the wheel drives and the 2 drums. The good thing is that it will work with reversable ESCs. I've tried smaller motors that will not work with the type of pulse an ESC makes. But these do fine and make a ton of torque.

The bad thing is that they are from UK, will cost ya in shipping. I'd estimate the price per to be about $28.00 before shipping. I used salvaged ones in my crane, didn't know about this place at the time.

My motors in particular:
https://secure.precisionmicrodrives....products_id=82

The home site:
https://secure.precisionmicrodrives.com/


They measure right at just over an inch around, just over 2 in long. Probably real workable in 1/16, if that's the scale you're working in.

On my drums, the motors actually go inside the drums and attach to a hub inside them to save space, and I used 2 motors per application partly because I got them free at the time. There are smaller motors to be had, but I question their use with ESCs, unless you know something I don't. If you do, PLEASE share that with me!!! I use RC racing "12 turn" ESCs, because they were all that was available. Cost more than the motors they drive!

I once even joined an RC racing forum to pick guys brains on the topic of reversable slow speed, low drain-high resistance/impedance motor control, but they didn't have any suggestions, they are all about speed. This forum is more what I hoped to find for some sort of tech support.

I have to admit, I have not posted in other peoples threads yet, I'm just kinda taking it all in, and am blown away by what some guys are building!!! And Im a bit lost here too. I'm going to have to learn what some of the terms mean and such. But I can tell good model building when I see it, and making it operational at realistic speeds is too cool! Dan

[RCLogger]

Glad you found the site Dan.

how did you set up your out riggers ?

greg

[ihbuilder]

thanks Dan , there are esc's that will work ,I'm sure . I'll have to research it though on the couple of links I have . I'll get back to you on that . If I can run all the functions on my rotator wrecker by screw drive I'll be happy

IHSteve

[BigZracingRC]

WOW! very impressive build!

[Southgate]

Greg, here's a rundown on the outriggers. They are a project unto themselves!


Each arm is milled from 3/8x3/4 aluminum bar. The inner parts of the arms are flat, the majority of the arm is flanged. the tops and sides of the flanged parts are cut a bit narrow so that when painted they won't get scratched off when sliding in an out (done manually. On the real crane I copied, each outrigger is operated by controls on each side the outrigger box itself, not from the cab)

Here are the basic components.


The aluminum "box" is square tube, and the plate that separates the arms is 1/8"flat bar. It has channels milled into it , and the arms hava a screw in them to stop the arm at full extension. You assemble the set, insert it in the box and small screws hold it in place.

L shaped brackets attatch to the boxes. (the box goes through it) and pins drilled in the "L" fix it to the frame on the carrier. Thes can be pulled for easy removal of the assembly for loading on transport trucks when weight restrictions require it. (OK, they will look really cool as a flat bed load when they're finished!)


Steel rod connectors, (I think they are called) are used for the jacks. They are hex shaped with threads on the inside, Home Depot sells them. To attach them to the arms, a round end was turned on the lathe.


A hole is drilled in each arm, the jacks inserted and held with a dab of superglue.


These brass tubes were worked to make the outer jack cylinders




They are superglued just enought o hold them in place, a clay dam was made. Then a piece of aluminum tube the size of the inner ram was liberally coated with vaseline and inserted up from the bottom to creat a space for the permanent rams, then the whole thing was put on a piece of clay to seal the bottom. Casting resin was poured into the top of the cavity, it is what holds the outer walls in place, and makes a solid top and bottom of the ram cylinder.




The resin was some old stuff I had on hand, and expanded out the top. I cut it off and filed to shape.


Now, this tube will be attached to the screw, and will move up and down with it, looking like a ram. I'm going to try to find a piece of antennae that has a chrome finish to look better than aluminum.



The picture with the screw didn't turn out. They will actuallyprobably be "operated" by turning the screw from the top by a small slot cut in the screw. This will be hidden so as not to look like a screw, and the feet of the jacks will hide the screw head there.

I hope this answers any questions, if not, feel free to ask! Dan

[ihbuilder]

Dan , have you looked into these http://banebots.com/pc/ELECTRONICS/BB-0309 I may be getting a bunch of them

IHSteve

[JAMMER]

Dan you are doing some nice work there keep it up. Ed

[RCLogger]

Dan that is a very detailed information regarding the outriggers, thanks. Down the road at some point I may build a cable log loader on a rubber undercarrage, so I have the outrigger hurdle to overcome..

greg

[Romelio]

This is a very interesting build. Great job I can't wait to see it finished!