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Daves956

Any ideas for this? / A 6 wheeled crane build

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This is the beginning of the body.

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And this is the majority of the radio gear and ESCs for it.

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The lunchbox wheels and tires and added on upper deck were removed and the chassis extension to the second axle was shortened by 2 inches which put the axles closer together. The rear axles were fitted with hex drives and the front uprights replaced with stock ones. I took the crane apart to decide on what could stay and found rack and pinion drive options for the boom extension and elevation.

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Next was fitting Tamiya worm drives into the elevation and boom.

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I added a power rail to the boom so it would have power but no cord.

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You can see the pickups on the inner boom behind it. The wheels and tires in the background are the size I want to use. those are on it just to find what worked for size

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I've been modifying the crane body a little bit to make it fit the chassis better. I'm far from done but it is an improvement in my opinion. The boom extension and elevation are functional but not controlled. I'm a long way from putting the radio and electronics in.

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Any thoughts about limit switches for the worm drives? They'll keep trying their hardest to move if you hit a firm mechanical stop, and possibly strip gears.

What do you think about some slot car track brushes for the pickup? The sponginess might make more consistent contact with the power rail...

The ideas and mods are looking good; I'll be following this to watch progress.

-Paul

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Thats a geart start dave . Have you though about powered jack leg supports ? The tamiya truck trailer legs would do the job well .

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Nice progress to date. Every project you start states this one will take some time but 2-3 weeks later it's all done !

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The limit switches would also need an over ride so that would be pretty hard to do. The slot car brushes will probably happen and a great idea. I did look at the semi legs x 2 and the price is a bit steep, same goes for retracting landing gear. Right now it's 6 of 7 channels used so outriggers will be tough. The rotate is going to be a hard one since it sits over the axles and no place for a servo or gearbox. Dave, I know what you mean and it's why I picked this one. I'm already stuck and far from what looks like the hardest part. Where on earth do I put a gearbox for the cable itself? The size cable it needs is something I couldn't find for the rothmans truck too.

The control of this is already giving me headaches. The 2 worm drives max out at 6 volts so how to do that with ESCs. The boom extension needs to be somehow tied with cable extension and then controlled seperate too. This came with sound and I'd like to use the diesel sound and beep beep revereing but it's 4.5 volt and originally controlled by a tethered control. The cable gearbox looks like it's going in the counterweight area and from there through the rotating ring and pivot point. Then offset to go around the inner boom then out the end, something like 6 90 degree turns to get it where it needs to be without hanging up or needing a winch to pull it out is a tall order.

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The limit switches would also need an over ride so that would be pretty hard to do. The slot car brushes will probably happen and a great idea. I did look at the semi legs x 2 and the price is a bit steep, same goes for retracting landing gear. Right now it's 6 of 7 channels used so outriggers will be tough. The rotate is going to be a hard one since it sits over the axles and no place for a servo or gearbox. Dave, I know what you mean and it's why I picked this one. I'm already stuck and far from what looks like the hardest part. Where on earth do I put a gearbox for the cable itself? The size cable it needs is something I couldn't find for the rothmans truck too.

The control of this is already giving me headaches. The 2 worm drives max out at 6 volts so how to do that with ESCs. The boom extension needs to be somehow tied with cable extension and then controlled seperate too. This came with sound and I'd like to use the diesel sound and beep beep revereing but it's 4.5 volt and originally controlled by a tethered control. The cable gearbox looks like it's going in the counterweight area and from there through the rotating ring and pivot point. Then offset to go around the inner boom then out the end, something like 6 90 degree turns to get it where it needs to be without hanging up or needing a winch to pull it out is a tall order.

lol @ Tall Order - well it is a crane

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I think I have every gearbox that Tamiya makes and it looks like the worm drive is the only one small enough for the winch cable or probably nylon line. If I cut the back of the boom cover and the counterweight enclosure I could get a straighter shot but I still have to go outside the inner boom to get there. I have a feeling the entire boom has to be redesigned with maybe a spring to return or something yet to be seen.

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I thought I was stuck on the cable lift but I found a gearbox that fits in the end of the boom so I don't have to route the cable or in this case nylon line everywhere to get it up there. It fits good and has plenty of torque at over 200:1 ratio. Now I'm completely stuck with no visible way to get power to it. The boom extends about a foot and it's a tight fit everywhere. Any ideas?

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How about a coil cord from a telephone handset? It'll stretch as the boom extends, and it will retract/take up the slack as the boom retracts.

It's not clear to me how much or how little space you have from the pic...

-Paul

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How about a coil cord from a telephone handset? It'll stretch as the boom extends, and it will retract/take up the slack as the boom retracts.

It's not clear to me how much or how little space you have from the pic...

-Paul

the middle piece is inner and outer booms together in the full retract position. The inner has the two gearboxes in it. If I cut the end by the black cased gearbox completely out I might have 2 inches and part of that is the circular pivot point on the left.

I don't think there's enough open space for a coiled cord. I have the 2 contact runners but I'd need 2 more since both gearboxes will probably be ESC controlled however I don't see a place for any more. I may try a loop under the inner boom but there really isn't enough open space or length to keep it from jamming things up.

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Thanks Paul. Coiled phone cord is 4 wire and that's how many I should have been thinking about. Sometimes I get caught up in adding something I forget the obvious. I'll remove the 2 brass tracks and do something that supports all of it, not just part. Ribbon cable or doll house tape spring to mind.

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I Removed the brass rails and made a 4 wire twisted pair. It loops all the way to the end and back down where the tracks were. I've run it quite a bit and it doesn't snag up on anything so one more problem solved.IMG_1520.jpg

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Since some of the motors are now in place and the body is coming along. I figured I'd better start looking ay the control issues. Here's a rough idea of how I think it might work.

Cable control and boom extension run on the left stick with a Tamiya DMD T01 dual controller.

Boom elevation on aux 1 using either a TEU 104 or a Tazer 15'

Boom rotation I'm hoping to use a high output metal servo on aux 2.

The right stick will be crane forward/reverse and steering.

One big question I have is the voltages for the 3 gearboxes now in place. If I turn the rates way down will it limit the voltage? Or do I need to resistor the outputs? I'd really hate to fry something but it's more than likely something will get cooked. Any advise on this?

I'm still thinking about legs but I'm down to one channel left and I'm not overflowing with great ideas on it at this time. The only channel left is meant for landing gear and it's just up and down.

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This is the light version of the crane controls so far. The DMD unit doesn't seem to like being programmed so it's out of there. I'll just use two normal ESCs in it's place. One thing that will be an issue is the on off switch for this. It will end up with 4 ESCs and the radio on off, so 5 poles. I've never seen one or even heard of one. Maybe just leave everything on and switch the battery? The battery or batteries are a question yet to be addressed.

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Dave the weight of the batterys should at least make it very stable when doing a lift lol . I'd try to mount them as loow as possiable and rearwards .

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The chassis has 2 mounting trays for batteries. I just hooked up multiple batteries so I could test it out. Part of this will have to be on a 4 cell battery to keep the voltage down. The rates didn't drop the voltage but the end point did just not enough for the lower voltage gearboxes. I'm going to have a look into mini ESCs since I'd rather not use that many of my tazers on a project that really can't use what they're meant for. I'm a little concerned about fitting all of that too.

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Well, I'm not sure if it's good news or bad. I can't find any ESCs at a reasonable price that will run on 4 cells. The tazers will but they are 250 amp and a bit much for the little gearbox motors. Everything I found for minis sell in the 65 to 80 dollar range and that's a bit much for what I'm doing. Part of the bad news is it would take all the spare ESCs I have to run everything. However Horizon has replaced the 15T with a new waterproof version and on Ebay they are as low as 29. It'll take a bit of rationalizing and some measuring but it looks like I'll be using the older 15Ts and replacing stock with the new waterproofs.

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Well, something had to go wrong. After 2 coats of grey primer and 7 coats of white Krylon the yellow is still bleeding in. I couldn't live with the cheesy color and decided on at least a primary white since every crane I see is that way. This is just the body not the boom so far and the boom would never take that much paint and still work. It looks like scrap to me. I'll pull the gearboxes and shelve the chassis for now or until another body comes along for this mess. Oh well

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I haven't checked up on this project for a while. Looks like you were making AWESOME progress!

Now it appears you are tossing the body? ACK! I guess some projects just don't work out, that's the nature of the hobby... :(

Seems odd that some primer wouldn't cover up the yellow..? Would love to see a pic of it?

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Dave i'd give it coat of black primer - yellow is a PITA to cover . Then use grey and finnally white . Dont chuck it as it is saveable .. Have you thought about doing it in RED - lots of cranes are that colour this side of the pond .

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We have 3 dominant crane companies here locally. The one that has red cranes is part of my job security. Whatever they touch they break, so red wasn't an option. I figured it would eventually cover but it didn't show any signs of it. It was getting thick enough to start loosing detail and with the white additions to the body it just looked hideous. I've already chucked it out. I was already to the point it would have to be stripped anyway.

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