Jump to content

Photo

MOC: Second chassis experiment


  • Please log in to reply
15 replies to this topic

#1
apemax

Hello all. This is my second chassis experiment. I made this mainly to try and make live axles on both the front and the back which went fairly well. I also tried to do return-to-center steering which didn't go very well. Doesn't work overly well but for a first attempt i don't think it's to bad. :) Also this is the first time I made a pair of seats from scratch instead of just using the ones from my 8437 Future Car.

A few of the problems with this model: the springs for the suspension are too soft and i don't have any harder springs so hence i used them, I don't think the drive train would be strong enough if there was a whole body on it and finally i ran out of pieces. hence I only made the front cabin.

As usual it's powered by a XL motor for drive, a M motor for the steering and it has the IR receiver and battery box. It also has a V12 engine and a front fan to cool the engine down. (Doesn't really need it, Just thought it would be cool. :) ) I also had to nick the steering wheel from my 8110 Unimog as i don't have any spare ones. The tyres however i didn't take from my Unimog, i managed to get a spare set of 4 of them so now i have 8 Unimog tyres. :) On with the pictures:

Posted Image
Posted Image
Posted Image
Posted Image
Posted Image

And now some pictures without the cabin on.

Posted Image
Posted Image
Posted Image
Posted Image

more pictures here: http://www.brickshel...ry.cgi?f=518238 (once it becomes public that is.)

And finally a video of it:

http://www.youtube.com/watch?v=XIQnDmTuyhk

Hope you like it. Any comments/questions welcome. :)

#2
McJobless

I think it goes without saying that, once again, you've crafted something rather amazing. It looks brilliant, although it's a little bit depressing you didn't have the parts to do any more...Nice work, and please do keep it up.

Quick question, did you achieve top speed in the video, or can it go faster? Considering it's a V12 engine... ;P

#3
apemax

Thanks Extreme. Yeah it would have been nice to make a full body but oh well.

Yep thats it's top speed in the video. I don't think the gear train could handle it going much faster.

#4
Phoenyx

Yep thats it's top speed in the video. I don't think the gear train could handle it going much faster.


Knowing that Tamiya uses the same material for the gears in their entry-level RC car kits as LEGO uses for all injection-molded components, I'd say you could potentially make it a bit faster.

Anyway, try widening the wheelbase. It will really help with the turning radius.

#5
apemax

Knowing that Tamiya uses the same material for the gears in their entry-level RC car kits as LEGO uses for all injection-molded components, I'd say you could potentially make it a bit faster.

Anyway, try widening the wheelbase. It will really help with the turning radius.


It's not the actually pieces that couldn't handle much more speed but the connections between the gears. It's not designed very well really. I've still got a bit to learn.

I know LEGO itself can withstand quite a bit of speed. This model can go a bit quicker but then it starts to grind gears hence I choose this particular gear ratio.

Yeah that's another problem with it. I tried to make it as wide as I could but the chassis ended up being fairly thin so it ended up being fairly thin. My next model I plan on giving it a wider wheelbase. At the front anyway... I also plan on making it a bit quicker too.

#6
Phoenyx


Knowing that Tamiya uses the same material for the gears in their entry-level RC car kits as LEGO uses for all injection-molded components, I'd say you could potentially make it a bit faster.

Anyway, try widening the wheelbase. It will really help with the turning radius.


It's not the actually pieces that couldn't handle much more speed but the connections between the gears. It's not designed very well really. I've still got a bit to learn.

I know LEGO itself can withstand quite a bit of speed. This model can go a bit quicker but then it starts to grind gears hence I choose this particular gear ratio.

Yeah that's another problem with it. I tried to make it as wide as I could but the chassis ended up being fairly thin so it ended up being fairly thin. My next model I plan on giving it a wider wheelbase. At the front anyway... I also plan on making it a bit quicker too.


It's probably grinding gears because it's heavy. Maybe a smaller chassis in general would work, something more along the lines of 1/10th scale rather than 1/8th? That way you could kill two birds with one stone and improve handling as well.

A wider wheelbase at the front but not at the back... Hm...

Spoiler


#7
apemax

It's probably grinding gears because it's heavy. Maybe a smaller chassis in general would work, something more along the lines of 1/10th scale rather than 1/8th? That way you could kill two birds with one stone and improve handling as well.

A wider wheelbase at the front but not at the back... Hm...

Spoiler


Yeah it probably is a bit to heavy to go fairly quick but then again this wasn't meant to go that quick anyway. I have made quicker models years ago like this one: http://www.mocpages.com/moc.php/152552 That had a good top speed but not very good acceleration.

I think i've found a way to get good torque and top end speed by combining a XL and M motor through a differential but i need another M motor to use that idea in a model.

Something like that yeah...

#8
Cyrem

Cyrem

    Founder

  • Administrators
  • PipPipPipPipPipPip
  • 3,835 posts
Have you tried a belt driven motor? This would reduce wear on your gearing and make it 4 wheel drive. You'll need two belts, one to the front wheels and one to the back.

#9
apemax

Well thats a interesting idea. I'd need to find some sort of belt to use though. It would certainly make the drive train a lot simpler but i'm not sure how good it would be with more heavy models.

#10
Phoenyx

Depending on how heavy the model is, you may end up having to use components from an RC touring car to build a belt-driven setup that doesn't slip under normal use.

#11
apemax

Very true. You can only get so much out of a LEGO motor and Gears before you start to have issues. Now if i had a LEGO buggy motor or two i could make a LEGO model go quicker as they are more powerful than most LEGO 9V motors. Alas they a bit expensive to buy. Might get one eventually.

#12
Cyrem

Cyrem

    Founder

  • Administrators
  • PipPipPipPipPipPip
  • 3,835 posts

Depending on how heavy the model is, you may end up having to use components from an RC touring car to build a belt-driven setup that doesn't slip under normal use.

Very true. You can only get so much out of a LEGO motor and Gears before you start to have issues. Now if i had a LEGO buggy motor or two i could make a LEGO model go quicker as they are more powerful than most LEGO 9V motors. Alas they a bit expensive to buy. Might get one eventually.


For best performance I'd consider buying an RC motor (maybe just a cheap 27T). You'll probably end up modding some LEGO for it to accept the belt (I'm sure you can figure something out here).

Actually... an experiment (This probably won't turn out great, but worth a shot) on the front and back end of the vehicle where your gearing is use a LEGO wheel and run the belt around it(you'll probably need some sort of edging to make sure it won't run off)... but you'll need a wheel with the cross hole '+', and put that to the actual wheels.

I'd try this myself, but by RC isn't belt driven.

#13
apemax

For best performance I'd consider buying an RC motor (maybe just a cheap 27T). You'll probably end up modding some LEGO for it to accept the belt (I'm sure you can figure something out here).

Actually... an experiment (This probably won't turn out great, but worth a shot) on the front and back end of the vehicle where your gearing is use a LEGO wheel and run the belt around it(you'll probably need some sort of edging to make sure it won't run off)... but you'll need a wheel with the cross hole '+', and put that to the actual wheels.

I'd try this myself, but by RC isn't belt driven.


That's actually a good idea. If you use two LEGO wheels with the tyres on them, connect one directly to the motor and then connect the other one directly to the rear wheels then use something like a fairly wide elastic band then that should provide a good amount of grip for the belt and lessen the amount of gears needed thus making it simpler and stronger.

I'm going to have to try that idea out on my next model.

#14
Cyrem

Cyrem

    Founder

  • Administrators
  • PipPipPipPipPipPip
  • 3,835 posts


For best performance I'd consider buying an RC motor (maybe just a cheap 27T). You'll probably end up modding some LEGO for it to accept the belt (I'm sure you can figure something out here).

Actually... an experiment (This probably won't turn out great, but worth a shot) on the front and back end of the vehicle where your gearing is use a LEGO wheel and run the belt around it(you'll probably need some sort of edging to make sure it won't run off)... but you'll need a wheel with the cross hole '+', and put that to the actual wheels.

I'd try this myself, but by RC isn't belt driven.


That's actually a good idea. If you use two LEGO wheels with the tyres on them, connect one directly to the motor and then connect the other one directly to the rear wheels then use something like a fairly wide elastic band then that should provide a good amount of grip for the belt and lessen the amount of gears needed thus making it simpler and stronger.

I'm going to have to try that idea out on my next model.


Great!

And if there is too much acceleration and you don't have the belt ridiculously tight it SHOULD cause some slip... resulting your LEGO being saved from snapping.

#15
apemax

Great!

And if there is too much acceleration and you don't have the belt ridiculously tight it SHOULD cause some slip... resulting your LEGO being saved from snapping.


Precisely. I've already snapped a 12T bevel gear in half because I tried to put to much torque through it. That was in my AP41 Trial Truck. Granted that's not the only LEGO piece I've broken...

I just realised I never spoilered the pictures in this thread.