[HELP] Building a MAN TGM 18.290 4x4

[Beck]

Hello everyone!

I have been working on a MAN TGM 18.290 4x4 fire truck and have almost completed the chassis. I worked on the front axle and rear axle+gearbox separately. After completing them and successfully connecting them, I reworked the rear axle+gearbox. I tried to put the two modules back together and found that the two modules don't line up (in the vertical axis) since I tampered with the rear leaf spring setup. Both modules are decently sturdy.

More Pictures

The truck will be longer than I had expected so I will have room to connect the two modules. Thus far I think there wouldn't be any consequences to continue building. What do you think? Do you agree with me or do you think I'm making a mistake?

[mahjqa]

I can't really comment on wether rebuilding it would be an advantage in this situation, but on the whole I've found that rebuilding something over and over and over again is an intrinsic part of building with Technic. It's something I've grudgingly come to terms with.

[AkiyamaWataru]

I would try to find a way to attach it properly alligned. Starting over would be needed if your chassis would be to soft and to weak. But you said it's solid. So try to get it to align. Maybe redo the connecting part. But dont start over completly

[jorgeopesi]

I've found that rebuilding something over and over and over again is an intrinsic part of building with Technic. It's something I've grudgingly come to terms with.

I can't be more agree.

[Bricksonwheels]

Mahjqa is speaking the truth. Its a design proces. I rebuild stuff all the time.

[Didumos69]

To me building itself - and designing in LDD - is the actual fun part, but I have to admit that the fun is even bigger when it all leads to something satisfying.

When you're building, your whole model is on top of your mind and you - sometimes slowly - progress to something that feels good. When all is finished, your build slowly moves to the back of your mind and after a few months you can't even remember why some design choices were important. So I would encourage you to not be reluctant when it comes to rebuilding over and over again if it get's you where you want to be. To speed up the design process you could also use LDD, but that's a matter of personal preference. LDD doesn't realy give a feel of how sturdy something is.

About your chassis. Even though you stated it is sturdy, it doesn't realy look sturdy. It bends a little under it's own weight. This is not necessarily a bad thing, because some of the rigidity can come from what you're building on top of the chassis. But to get the chassis itself more sturdy I would make sure all modules (front, center, rear) are connected on at least two levels. It appears to me that your front module is connected to the center on just one level. Another thing that's important to make a chassis sturdy is to make use of beams in all dimensions, vertically, widthwise and lengthwise and also make use of parts that make square angles (5x3 liftarm, 5x7 frame etc.) in all dimensions.

For my Steppenwolf chassis - also composed from a front, center and rear module - I started with a main structure of lengthwise and widthwise beams that run from bumper to bumper. I added vertical stability during the build process, mainly with 5x3 liftarms and 5x3 frames. Throughout the rest of the design process I never made any compromise to this main structure.

Edited September 1, 2016 by Didumos69

[Kristof]

I don't recall any instance where re-designing and further re-building had negative effect on my model. In fact, in nearly 100% occasions, I find out to my surprise that I can include worthy improvements which I didn't see before.

[steph77]

+1.

I build about 14 versions of my last truck frame and about the same amout for it's crane.

The important thing in this process is to fix all the problems one by one and coming at last with the cleanest design as possible.

This is what you can think about are for instance :

-do i have use as few parts a possible?

-Can i simplify it with the same functions?

-Can i eventually compact this design?

-Do all axles and movig part rotate and work smoothly?

-Do my frame have neutral effect on moving parts when stressing it?

-Do my build fits with the design i am searching for?

Once you answer yes to all these questions a the same time....you probably will have build and taken it in parts a few times

Edited September 1, 2016 by steph77

[jorgeopesi]

For me there is not more fun that design arms and linkages for machines, one millimeter makes the difference and you have to test over and over again looking for best travel possible.

[Victor Imaginator]

When i building, i just rush and add more and more parts. When i think that i achieved desired functionality - i start to remove parts or replace complex connections with simpler ones. I never rebuilded my MOCs, changed almost 80% of them while building - yes, but if i rebuild it from scratch - it's another MOC for me.

[nerdsforprez]

Ditto to all that has been said. Also, keep in mind that many builders, myself included, have many projects going at once. Because so much rebuilding goes on, it can be helpful to have several projects going at once to break up the monotony.

[jorgeopesi]

Ditto to all that has been said. Also, keep in mind that many builders, myself included, have many projects going at once. Because so much rebuilding goes on, it can be helpful to have several projects going at once to break up the monotony.

I think just the opposite, I can´t have more than one MOCs at the same time... and in that rare case, until I dismount one of them the other does not begin to flow properly. Now is this rare case I am working in my TC10 entry and I still have the Porsche 911 of rebrick contest and every day I look it wanting to unmount .

[TheMindGarage]

I think just the opposite, I can´t have more than one MOCs at the same time... and in that rare case, until I dismount one of them the other does not begin to flow properly. Now is this rare case I am working in my TC10 entry and I still have the Porsche 911 of rebrick contest and every day I look it wanting to unmount .

I tend to be limited by parts - I only have enough electronics and panelling for one model. But when I'm doing the bodywork of one MOC, I find it hard to focus since the part I really enjoy is making the mechanism. So I tend to overlap my MOCs a little bit - while I'm doing the bodywork of one, I make a start on the mechanisms (such as the suspension) of the next.

As for rebuilding, I do it all the time. I recently dismantled the entire rear axle of my current WIP in order to build a better version. When working on new gearbox designs, I rebuild many, sometimes dozens of times. The more you rebuild, the better your end result will be - you might have more space for another function!

[Beck]

Thank you all for your comments, they were very very helpful! I will probably opt for a rebuild now.

About your chassis. Even though you stated it is sturdy, it doesn't realy look sturdy. It bends a little under it's own weight.

The bending you see is the result of no actual connection at the moment the 1x4x2 L beam slots in-between the two liftarms on the gearbox which held the two parts upright so I could take the picture.

Edited September 1, 2016 by Beck

[Imanol BB]

Maybe you could make a similar chassis of the 8110, or make an smaller version of Efferman´s Unimog UHN, which has a very flexible but yet robust chassis, which bends like many real life firetrucks like this one you are building.