[WIP] Chassis Project

[Phoxtane]

I've started on a chassis that will eventually be used to build a supercar with, as per the unofficial Technic rite-of-passage:

Notable features include a floating differential setup that's borrowed from Thirdwigg's 8081 RT MOC (found here: http://thirdwigg.com/2014/01/12/8081-rt/)

The always necessary underside shot:

The right and left sides, respectively:

The back end:

And a shot from the top:

A lot of this is placeholder; the entire front steered suspension setup is also borrowed from Thirdwigg's MOC and as such is held on with the power of Grayskull wishful thinking. In addition, the chassis is about as short as it will get due to the fact that the drivetrain is artificially long to avoid issues with the half-width offset generated by the floating differential, and the servo motor is set directly end-to-end with the L-motor. Finally, I think the chassis overall is a little too tall for a supercar, and I would like to lower that somewhat.

Basically, I'm looking for what I can improve to make this a bit more compact (and yet still have room for a battery, something essential I forgot to put into this) and what I can do to make it stronger. This project is derived from the thread I made recently about developing a compact suspension (http://www.eurobricks.com/forum/index.php?showtopic=97809) - as you can see, I ended up using Thirdwigg's solution as it was going to be much better than anything I could come up with in a reasonable amount of time. Let's finish off this post with some nice pictures of the rear drivetrain, with and without the various supporting elements!

[Zerobricks]

I suggest you to use a C frame to hold the differential as it will be less likely to slip. Aslo the 3 studded long axles are eventually gonna slip out of the differential.

[Phoxtane]

I suggest you to use a C frame to hold the differential as it will be less likely to slip. Aslo the 3 studded long axles are eventually gonna slip out of the differential.

I'll have to mock up another rear section to try out the C-frame, but how do I deal with the ball joint? Should I be using the female ball joint cup to hold the other end? If I do so, I run into the issue of the cup being offset a half-width from the rest of the frame. As for the 3L axles, is there a way to help keep them in place?

[Edwin Korstanje]

Your chassis looks promissing, but i don´t seen any supercar chassis in it.

I hope that i have it wrong .

Edited August 4, 2014 by VFracingteam

[Phoxtane]

Your chassis looks promissing, but i don´t seen any supercar chassis in it.

I hope that i have it rong .

I never said I was any good, mind you!

That said I do want to be able to drive it around, so I haven't got as much room to play with all the things that make a proper supercar. I do hope I squeeze in a fake engine somewhere... maybe it'll end up being a mid-engined supercar?

[Rishab N]

I like it although i feel like its more of a SUV or pickup chassis

[Phoxtane]

I like it although i feel like its more of a SUV or pickup chassis

Is that because of the dual shock absorbers in the back? I feel like that's a bit out of place... I will have to rebuild the back end around the new C-frame so I think I can change that as well. Perhaps I can cut down the blockiness as well.

[Bzroom]

Looks cool!

With all that space you could fit two XL's in there easy. What about batteries and receivers?

You'll notice in race car chassis that the main section of the chassis (not the roll cage) rare extends above the height of the tire. The lower and wider the better. It will often expand in width between the wheels to accommodate the passengers, fuel, transmissions. If you think of the chassis as a tube, you'll want to have the largest radius possible for a given amount of material. As the structure moves to the outside, it will produce a larger torque resistance to chassis flex and allow more room for the internal components. A smaller/denser tube will have less resistance to torque.

Great books on car chassis:

http://blog.autospeed.com/static/images/blog/2008/10/racing-and-sports-car-design.jpg

http://www.themotorbookstore.com/howtomayocar.html?gclid=CLfA09u4-78CFQg0aQodkDsAMA

Random inspiration:

https://www.google.com/search?q=gt40+chassis&es_sm=93&tbm=isch

[Jim]

Slightly off topic: How did you make the renders/sketches? Google Sketchup? They are pretty awesome!

[TheItalianBrick]

Slightly off topic: How did you make the renders/sketches? Google Sketchup? They are pretty awesome!

Sorry Jim for the off topic but I'd like to get the chance ,talking about renders. to make a deep post about it as I do these things daily for my job, if you let me!!

[Jim]

Sorry Jim for the off topic but I'd like to get the chance ,talking about renders. to make a deep post about it as I do these things daily for my job, if you let me!!

Feel free to make a post in the LDD forum. Always interesting. However, I am specifically interested in these renders.

[TheItalianBrick]

Feel free to make a post in the LDD forum. Always interesting. However, I am specifically interested in these renders.

You cheeky! :tongue:

[Lipko]

More off, if you do make an LDD topic, please link it here.

[Phoxtane]

The renders were done with LDD-to-POVRay. The model itself was built in LDD, then put through the converter, and finally rendered via POV-Ray. It's a pretty good service but it requires that you build your model with LDD, which is a bit of a problem considering the bugs I've run into with the latest LDD update.

[Jim]

The renders were done with LDD-to-POVRay. The model itself was built in LDD, then put through the converter, and finally rendered via POV-Ray. It's a pretty good service but it requires that you build your model with LDD, which is a bit of a problem considering the bugs I've run into with the latest LDD update.

So the Sketchy look can be achieved by using LDD-to-POVRay?

More off, if you do make an LDD topic, please link it here.

Yes, please do!

[Phoxtane]

So the Sketchy look can be achieved by using LDD-to-POVRay?

Yes, it is the outline option when in the converter. I have found it speeds up the render dramatically, and is reminiscent of cel-shading!

[Phoxtane]

I am having issues with coupling the L-motors to the new back end, and I'm not really sure where I can go from there. I'll try and get pictures once my shift is over (super helpful, I know).

2 L-motors makes sense to me, as that's double the power I can send to the wheels and they're a lot easier to work with than XL motors. The problem is that darn C-frame. Although Zblj is right (the old frame let the bevel gear deflect away from the differential any time load was applied), the ball joint is getting in the way of making a clean connection between the back end and the motors. I would connect the motors perpendicular to the drivetrain, one on each side of the chassis, but they would end up being wider than the wheels themselves, which is a bit of a problem. XL-motors, which are shorter, have the same problem as well! I'd like to do two things: see if I can't replace the C-frame with another part that will do the same thing but without the ball join, and connect the motors to the drivetrain.

On another note, I shortened up the back end a bit as I was able to remove the now unnecessary second shock absorbers. So that's one thing accomplished!

Edited August 7, 2014 by Phoxtane

[Thirdwigg]

Thanks for the shout out. I found the rear suspension worked well, but I never gave it a lot of power. If you need to add a lot of power consider removing the wheel hubs and creating your own so you may use a U-Joint rather than the CV-Hub connection. Like this:

[Bzroom]

It sounds like you're trying to space optimize way too early. You wont need to get the motors in absolutely tight with the rear end. You may find that puts the motors in the way and you actually need to spread them out to make room for more crucial components. Best to keep things iterating and loosely connected until you're absolutely sure that all components have been given a home, then you can optimize.

[Phoxtane]

So I've run into an issue that isn't so easily solved with a few bricks being moved about. I'll be going into my first year of college here in a couple weeks, and because I am living in a dorm, I won't be able to bring my Lego collection with me!

Naturally of course this means I can't exactly work on any of the projects I'd like to...

Considering how small my Technic collection is compared to the rest of my Lego hoard, I may however be able to move some of it into my dorm temporarily. Either way, my parents have told me that I can't come back to the house for at least three weeks after move-in day, so as to have me get out and doing things for once. As such, I'll be putting this and any other projects on hold for at least five weeks, if not until I can get something worked out where I can come back to the house and work there*.

So, there we have it. I'll still be lurking around here, just unable to actually build anything myself!

*We live in the same town as where my college is, so it's not like it's all many hours away!

[Hrafn]

So I've run into an issue that isn't so easily solved with a few bricks being moved about. I'll be going into my first year of college here in a couple weeks, and because I am living in a dorm, I won't be able to bring my Lego collection with me!

Consider it an opportunity, rather than a problem! Lego will be there whenever you want to return to it, but college can (and should!) be a tremendously valuable experience, both in terms of academics and personal growth and exploration. Have fun, try a lot of new things, and get to know a lot of different people. You'll make lifelong friends and memories.

Back on topic, I like your chassis but the proportions are a bit off for a supercar (or a non-super-car), at least with those wheels. I suggest going with smaller wheels (maybe the new 49.5x20 tires). Most cars have a wheelbase of around 4-5 times the diameter of the wheels. Your wheelbase looks to be about 23 studs = 184mm, so tires of diameter ~45mm would be about right.

The ratio of width to length looks good if slightly narrow.