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I knew there would be backhoes with class tyres sure :laugh: . It was the first thing I thought but a backhoe deserves more time that I had, it is like build a wheel loader and a excavator all together, it has to be perfect because it has a lot of linkages and movements that I wanted to represent perfect, so I decided for something more reasonable for the time we have. Good luck with it is a shame not being able to see their development, build it perfect because I have the same eye for machinery as others for cars :wink: .

Just Unimog tyres. The problem with Claas tyres is that there's no proper scale bucket for the excavator, as far as I know, and even the long cylinders would be somewhat off-scale. And the front bucket is a bit too "specific" (from the Volvo). And most importantly, too big and too expensive :)

EDIT: Don't expect perfect linkages and movements as I'm not an expert in machinery and time is too short for deep research.

Edited by Lipko

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EDIT: Don't expect perfect linkages and movements as I'm not an expert in machinery and time is too short for deep research.

I'll be honest, most people copy what lego builds for machinery, another people places cylinders in any way and does not care if the machine moves realistically and a minority does really well, some machinery of great fame has a ridiculous movement but still has successful... I don´t know if you have seen my edit on my previous message, I write again. My advice would be to go for a medium-small backhoe with class tyres this way you will have maximum space for everything, like this, it is not impressive but it would be possible to put everything. Unimog tyres would be good too. I know I am crazy for machinery but for me failures in machinery are like failures in cars, everyone see them. You are right, right, right with the volvo bucket, it is too much specific and terribly long to tilt you lose the entire height you have gained with the arm.

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Edited by jorgeopesi

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Sorry, I only build models that look good in real life too. And I don't like those toyish "compact" machinery...

I think I can squeeze everything in. Maybe I'll have to sacrifice some stuff (like the suspension, joystick, sideways movement of the excavator). But if TLG managed to fit everything into 8455, I think I'll be okay with a bigger model.

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Sorry, I only build models that look good in real life too. And I don't like those toyish "compact" machinery...

I think I can squeeze everything in. Maybe I'll have to sacrifice some stuff (like the suspension, joystick, sideways movement of the excavator). But if TLG managed to fit everything into 8455, I think I'll be okay with a bigger model.

You know good that I don´t like compact machinery too :laugh: , everything you've done has been fantastic this will not be different.

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... go for a medium-small backhoe with class tyres ...

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That would be crazy huge creation right? Plus both front and back bucket would have to be brick built (unless you want to use Volvo shovel for the front, but then there is that wedge loader shape...). That would be crazy project :) And I agree with Lipko that such machine is not worth it :D The proportions of these small backhoes are funny - perhaps call them cute but who wants heavy machinery to be cute?? :D

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Maybe a stupid idea, but for the return to center you could use a soft shock absorber on each side, they'd stabilize the steering when there's no pressure in the small cylinder?

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Maybe a stupid idea, but for the return to center you could use a soft shock absorber on each side, they'd stabilize the steering when there's no pressure in the small cylinder?

I think it wouldn't work very well. Both shock absorbers would have to be half-compressed in the 'center' position. Given that the soft spring has close to constant stiffness on most of it's travel (invariant to the compression), there won't be much of an counter action when one is slightly more compressed and the other a bit released. Eventhough it wouldn't harm, there is a little chance that this could overcome just the damping in the small cylinders, not to mention the friction in the hinge and most importantly, the resistance against steering of the vehicle itself :)

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Return to center with pnuematics is possible, and I'm currently working on a road grader that uses it for both the articulation and front wheel steering. It uses a servo to control a valve. I'll have a WIP thread up in a couple weeks maybe.

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Return to center with pnuematics is possible, and I'm currently working on a road grader that uses it for both the articulation and front wheel steering. It uses a servo to control a valve. I'll have a WIP thread up in a couple weeks maybe.

I have seen servos for this but I don´t like the idea for this contest, I think everything manual is perfect for pneumatic functions. Servo and battery need a lot of space for a pneumatic no RC MOC but anyway good luck I want to see your grader too, it is a great contest to see machinery, I can see ideas, linkages, tracks everything I like :laugh: . I don´t comment the pneumatic ideas because I don´t know enough to do it, at the moment... in 3 or 4 pneumatic MOCs more sure I will.

Edited by jorgeopesi

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Fake v16 engine on board and working, It is not a function that going to help me to win but it's been fun inserting it. Now another challenge put an pneumatic openable hood, I don´t have any idea where to put the switch, the cylinder neither the tubes for them but it will be fun again :laugh: .

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I discovered an awesome machine while I was waiting for the class tyres, the caterpillar 994 mono boom and it is my chance to achieve a medium, realistic, very playable and strong MOC. Its main feature is the narrowness, only 6 studs between wheels in order to get a giant appearance using the 8265 bucket and unimog wheels, I am very happy with it, of course it has a large travel of arm and bucket, using the entire travel of the cylinders.

I love the way the 16 cylinder engine looks, but if you still building this Cat 994 it (must)belong to be yellow and not LBG. :wink:

Edited by Edwin Korstanje

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I love the way the 16 cylinder engine looks, but if you still building this Cat 994 it (must)belong to be yellow and not LBG. :wink:

You are right but there are parts of the engine that don´t exist in YELLOW so I preffer LBG or BLACK or even BLACK with YELLOW I don´t know yet. I want to cover the MOC and then see what is the best or less worst color to use.

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I like the progress that you are making on this project. Your mining truck worked out really well and I think this will too!!

Thank you, IMO the mining dumper is one of my best MOCs, I would like to see them together.

More progress, pneumatic cylinder to lift the bonnet placed (instead the red liftarm, I haven´t got more small cylinders :wall: ). It will be under the bumper so we can´t see it, I just need to put the switch and tubes.

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I think it wouldn't work very well. Both shock absorbers would have to be half-compressed in the 'center' position. Given that the soft spring has close to constant stiffness on most of it's travel (invariant to the compression), there won't be much of an counter action when one is slightly more compressed and the other a bit released.

Just a note, LEGO shocks are just simple coils and therefore follow Hooke's law i.e. compression force is linearly proportional by some factor to their compression). Having two in half compression in the center position would work in theory. You'd just need stiff shocks to do this, because of the model's weight and the tyres' friction against the surface. Consequently you'd probably also need the normal sized pneumatics instead of the mini ones to turn the model.

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^ Correct. (well in the matter of fact, Hookes law is simplification - Castiglian theorem is more suitable for coil springs, but the base is the same). The thing is that for soft spring, the factor is very, small - the slope of the (almost) linear function is minimal. Therefore, the difference between the force for, lets say, 1/4 compression and 3/4 compression is insignificant - not in theory surely in this application.

Not even stiff shock absorbers would be suitable for this, I believe. But then again, It may work bettet than I anticipate :D

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I am sorry guys, my google translator is fuming and I don´t understand almost nothing :blush: . A easy poll, v16 fake working engine vs air tank.

V16 advantages - realistic engine and transmission.

V16 disadvantages - increasing the number of parts, reduced structural integrity, less like a Lego set, it adds nothing to the contest.

Air tank advantages - with one more switch I could choose when to use it for increase the speed, more simplicity, better structural integrity and Lego set appearance, adds to the contest.

Air tank disadvantages - you may never use it :laugh: , unnecesary transmission.

Edited by jorgeopesi

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Since it's pneumatic contest, I think that the air tank is considerable option :) I have never got my hands on it though - does is in fact do anything? Could you possibly make a video of the functions WITH and WITHOUT the air tank?

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Since it's pneumatic contest, I think that the air tank is considerable option :) I have never got my hands on it though - does is in fact do anything? Could you possibly make a video of the functions WITH and WITHOUT the air tank?

You already have a video using the air tank in the first page, but I put it again. It is fast and abrupt, but can switch between one system and another (direct manual pump or with air tank) using a switch would be fine, after all the fake V16 engine was a challenge for me and I saw that I was able to overcome it.

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More progress or not, I'm stuck in the engine, if I do a 988 instead a 994 I could put a smaller engine (only 6 cylinders) and a bigger cabin. I put together all switches and I added one more pneumatic function, it could be an adjustable blade or a log loader for wood. The new manual pump will be between the engine and the steering switch. 5 pneumatic functions I think will be enough for a medium MOC.

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Edited by jorgeopesi

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I have new pneumatic pieces, a new manual pump and 3 large thin cylinders, I think the old pump works better but new one is fine. After one week out from home with my children (2 and 4 years) playing with the wheel loader I am glad to say that only the fake engine was disassembled, so the machine is as strong, compact and playable as I wanted. I will try to finish it but working far from home I will build without Lego, I hope I can do it.

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Nice, but what's with the adhesive tape? Is it even allowed? How about using rubber rinds instead?

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