[HELP] First time building in a long time!

[wumsi]

Hello people!

I coudn't resist and bought a 42030 and was fascinated by all these new parts(Im was stuck in the year 2000 :D). I discovered LDD and started building a car. With these new remote controll capabilities and motors and stuff - it's quite a lot to think about.

I'm looking for some guidance. I'm not really sure about my design so far. I really want to be able to drive around with it. I don't know how strong the new motors are, if my axles make sense. Would be nice if someone could take 5 minutes and look over my progress so far. I uploaded the .lxf file

thanks!

[Saberwing40k]

Okay, not bad for a first timer, but there are a number of issues.

1. You've got some extra parts in the .LXf file that make the bounding area for the model really large. I tried zooming out, and it is so large that the model becomes invisible. You should probably revise that.
   
2. Live axle and independent suspension do not really mix, at least not the way you've done it. An axle should be either live axle , or independent, not both.
   
3. You have not really geared down enough. if this vehicle were built, it would be really fast, but have no climbing power. Also, Power Functions XL motors have an enormous amount of power, relatively speaking. 4 may be a bit much for a first creation.
   
4. There are a number of bracing issues as well, especially by the motors. a half stud offset like that is not a good idea, especially how you've go the motors braced. If this thing were actually built, the gears coupling the motors would start skipping, as the motors would naturally want to force themselves away from each other. Also, the torque tubes are not connected that well. your suspension connections are also probably not going to work, there is no linkage to keep the axle straight, and two gear racks on each side of the axle is unnecessary.
   

You've also made a fairly common mistake, and used LDD as a design tool for Technic models, which is really hard to do, as there are some connections in LDD that are difficult if not impossible to make in real life. Also, if you are inexperienced, it's all too easy to make things that will not hold together in real life, where we have to deal with gravity and torque, and all that nonsense.

But, there is hope, and other ways of gaining experience. Try building other people's creations, and seeing what works for them. Also, there are several databases with set instructions, which will help as well. Rebrickable.com is actually a great resource for beginners, as all of the creations posted there have instructions in some format. The site also allows you to plug in the set numbers of sets you already have, and will tell you what else you can make with those sets.

Finally, I'd suggest that you keep things simpler at first. Maybe just make a simple vehicle with rear wheel drive and front wheel steering, and work up from there.

[DrJB]

The main comment I have is that the frame appears rather weak (not stiff enough in bending and torsion), and it will most likely bend. It is the intent that the springs (shock absorbers) take on the deformation, not the frame.

Also, you're using 4 XL motors and that is quite an amount of power. Some demanding applications I've seen use one motor per axle (per tire). Here you're using 2 (in tandem) for each axle. While this for sure will give you more grip/climbing ability, I'm not sure the weak elements (axles and gears in the differential) can handle the high torque.

[Rockbrick]

LDD is great - building and realising all of the above, priceless - go build, make mistakes then ask some more questions and of course share photos!

[Zerobricks]

This is your first LDD model? Putting asides some technical issues, you are really good at LDD! I like the way you made independent suspension. But as others said one suspension type is enough

Edited January 2, 2015 by Zblj

[wumsi]

Okay, not bad for a first timer, but there are a number of issues.

There are a number of bracing issues as well, especially by the motors. a half stud offset like that is not a good idea, especially how you've go the motors braced. If this thing were actually built, the gears coupling the motors would start skipping, as the motors would naturally want to force themselves away from each other. Also, the torque tubes are not connected that well. your suspension connections are also probably not going to work, there is no linkage to keep the axle straight, and two gear racks on each side of the axle is unnecessary.

You've also made a fairly common mistake, and used LDD as a design tool for Technic models, which is really hard to do, as there are some connections in LDD that are difficult if not impossible to make in real life. Also, if you are inexperienced, it's all too easy to make things that will not hold together in real life, where we have to deal with gravity and torque, and all that nonsense.

I think, there shouldn't be any impossible connections, but i really didn't think about the motors torque and how they would probably just bend themsels apart. I did the double suspension just for fun, but it really would be easier(and sensible) to only do live axles. Thank you for your imput. I guess i will start completly new. Didn't take that much time to begin with !

This is your first LDD model? Putting asides some technical issues, you are really good at LDD! I like the way you made independent suspension. But as others said one suspension type is enough

I know "real" CAD Software and Lego, i just didn't know something like LDD existed :D

[wumsi]

So, I started from scratch, i put the steering on the axles. If these XL motors are so powerfull i guess i could try my luck on one of these cool transmissions :D

[Zerobricks]

I see you were inspired by 9398. Few remarks. Its too long and high. You can try to reduce the suspensiona ngle and length. Also shorten the steering arms so you get a better steering angle.