[WIP] SUV-SuperCar

[AkiyamaWataru]

Hey guys,

now I'm posting a car I'm working on.

Following features are planned:

• 4 Wheel Drive
  
• Full indipendent suspension with doublewishbones
  
• Steered front axle
  
• Realistig Axle Geometry (no active camber for now)
  
• portal axles
  
• Transversal mounted midship v6
  
• 2 seats
  

Shape and other features are not fixed for now

An old portal axle i will have to reenforce due to splitting under torque

Thanks for comments

[Didumos69]

To be honest, the term SUV supercar sounds a bit controversial to me. However, there are examples that come close, like for instance the Lamborghini Urus, but I doubt whether such cars would use portal hubs.

Still I like the ground clearance that you have. I would love to see someone building an AWD supercar with substantial ground clearance - and preferably a little bit more than the usual 1-stud suspension travel. The Lamborghini-based Italdesign Parcours is one of my favourites. It comes with adjustable ground clearance.

Anyway. I'd say, get rid of the portal hubs, but hold on to the ground clearance. Good luck!

[JJ2]

Looks good but you should instead of using 2 M-motors is the front just hook the front up to the 2-L motors using U-joints

[Jonfensu]

Looks good but you should instead of using 2 M-motors is the front just hook the front up to the 2-L motors using U-joints

Maybe they are there just for testing (?)

[AkiyamaWataru]

Hey guys,

thanks for the comments.

First I won't build new portalhubs.

For the suspension travel: for now it's about 4 Studs.

I want to use a primary and a secondery drive train. There for I implemented 2 sets of Motors.

The L-Motors are for Main-Propulsion. The M-Motors are secondery. I want to keep them as an experiment.

Like hybrid super cars I wanted to build a secondery drivetrain for front-axle.

[Didumos69]

For the suspension travel: for now it's about 4 Studs.

:thumbup:

Edited May 12, 2016 by Didumos69

[AkiyamaWataru]

Hey guys!

A short update from my side. I just finished the rough chassis und positioned the steering rack.

What I did as a list

• flipped the outputs of the rear-wheel-drive-motors to the back of the car. It's more convenient for cable routing
  
• created the main longitudinal beams for the chassis and now have the geometry for the car
  
• simplified the front wheel drive. Dropped the 2 M-Motors and replaced it with a single L-Motor
  

Now some Pictures:

the chassis section

side view

total view

modified wheel hub with elongated attachment for steering link

engine config

And again: Thanks for Comments

PS for Didomus:

Ground Clearing of Chassis is 4 Studs, The Bearings for Lower Wishbones have 3 Studs Clearance

Suspension Travel: It's a bit shorter then expected but i have about 20mm (2.5 Studs) of Travel

And for now I drop the Portal Axles

[Didumos69]

Ground Clearing of Chassis is 4 Studs, The Bearings for Lower Wishbones have 3 Studs Clearance

Suspension Travel: It's a bit shorter then expected but i have about 20mm (2.5 Studs) of Travel

And for now I drop the Portal Axles

For a supercar that's still substantial clearance and travel. Nice to see that you are trying to incorporate such features.

[AkiyamaWataru]

Hey Guys,

an update from my side.

new stuff:

• Steering Rack has been build and testet with a testrig (i have no servo yet)
  
• Battery Boxes have now a mounting mechanism for them
  

I found a problem i still can not solve:

While driving the drive-shafts of the front axle move to the inside and dislodge from the wheelhub axle. I use the new

CV-Joints on the diff-side of the suspension. Is there a way to stop that or force the parts back while steering?

If further information about the construction is needed, I can upload a LXF-File with the construction

[TheNextLegoDesinger]

maybe some pictures can be handy. if i see some places for improvement, i'll be right here to help you

[Didumos69]

I found a problem i still can not solve:

While driving the drive-shafts of the front axle move to the inside and dislodge from the wheelhub axle. I use the new

CV-Joints on the diff-side of the suspension. Is there a way to stop that or force the parts back while steering?

If further information about the construction is needed, I can upload a LXF-File with the construction

Do you mean that also the U-joint dislodges from the wheel hub axle? Did you try placing two half bushes on the 3L axle between the CV-joint and the U-joint? That will at least prevent the 3L axle from being eaten up by the CV-joint.

I had something similar once. The shaft of the CV-joint allows the 3L axle to move in and out while steering, which is necessary given your steering setup. However, when torque is applied the shaft tends to pull the 3L axle in, bit by bit, turn by turn. In my case the result was that the CV-joint pulled itself out of the differential.

Edited May 18, 2016 by Didumos69

[AkiyamaWataru]

Didomus thats the failure I have. I will try the double half bushes as a solution

Edit: Your solution works :) Thank you

Edited May 18, 2016 by AkiyamaWataru

[Lakop]

I like this. Those battery boxes must add some weight. It's taking shape.

H

[AkiyamaWataru]

For now only obe is filled but yes its getting heavy. The bigger problem was fitting them.

[Didumos69]

Didomus thats the failure I have. I will try the double half bushes as a solution

Edit: Your solution works :) Thank you

As for the battery boxes; they keep the center of gravity low and that's a good thing.

You can read the increased weight from the suspension. You might end up needing two shockabsorbers for each axle . Or you could consider using independent lengthwise torsion bars for the upper wishbones.

Edited May 18, 2016 by Didumos69

[AkiyamaWataru]

Hello Ladies and Gentlemen,

I have a short update for you. I fitted a newly arrived servo and a steering system and what can i say: I am not satisfied.

After some drive tests I realized the turning radius is ginormous. I will be implementing a 4 wheel steering. For now a picture of the car

The wiring is preliminary. I still need a second s-brick. The black s-brick-like/case thing is just a placeholder.

But that will take some time, as I have to rebuild the entire chassis.

[AkiyamaWataru]

Excuse me for double posting. I'm wondering wether positiv caster is needed for a steered rear axle?

[MaxSupercars]

I can advise you to invest in LiPo battery and you save a lot of weight and gain better performance. BB weights ca. 200g x 2 = 400g only BBs. One LiPo which weights 70g can feed 2 L motors with no problems... You save 370g what is a lot...

Max

Edited June 12, 2016 by MaxSupercars

[AkiyamaWataru]

Thanks for the hint. But lighter batteries won't help with it's turningradius.

[Lego Nerd]

Excuse me for double posting. I'm wondering wether positiv caster is needed for a steered rear axle?

That's kind of an interesting question. According to this article, the castor in the front is to return the wheels back to center. I'm not really sure whether the back axle would need that, because the back axle would ordinarily only steer a few degrees.

If it's easier, I would mostly copy the front suspension setup to use at the back.

It might help the turning radius if your steering arms were shorter.

[Didumos69]

Positive caster - as in your front axles - means that the steering axis is tilted slightly backwards. This causes the tyre to touch the ground behind the point where the imaginary line following the steering axis touches the ground. The effect is that the wheel wants to trail the steering axis, just like a wheel of a shopping trolley wants to trail its steering axis. This gives a car straight-line stability. Unsteered rear axles don't have a steering axis, so they don't need this kind of effect. However when rear axles are steered as much as the front axles, then there would be as much reason to apply caster angle to the rear axles. In that case you also need a steering axis that is tilted backwards, just like the front steering axis (so not mirrored). If it's only a few degrees steering angle, then I wouldn't bother.

EDIT, when axles are driven, caster, camber and kingpin inclination need a fine balance. This is an easy to read article about proper angles.http://www.motoiq.co...-and-Scrub.aspx

Edited June 12, 2016 by Didumos69

[AkiyamaWataru]

Thanks Lego Nerd and Didumos.

@Didumos I'll have a read into the article you mentiond :)

[AkiyamaWataru]

Sorry for double post, but I have a reason. The chassis is redesigned. I went through 2 iterations to come up with this one.

I happen to implement some things:

• All Wheel Drive
  
• All Wheel Steering
  
• Existing Caster Angle and Kingpin Inclination
  
• Working double wishbone suspension
  
• Portal Axles with 1:1 ratio
  

Front Supension:

Now there is a furry helper (aka Cat/Jacky) for scale

And 2 other Pictures to complete the post: the belly shot

Picture with Wheels:

One thing is still to say: The wiring and the positioning of the SBricks (you read correct SBricks I have two now) and Battery Boxes are preliminary.

And now a hint: Every Picture is clickable

Greetings Akiyama Wataru

[Victor Imaginator]

Your cat is really small... Or your chassis is pretty big) I like scale and suspension setup, nice kingpin solution.

Edited July 12, 2016 by Victor Imaginator

[AkiyamaWataru]

It might be the size of the chassis. It has a wheelbase of about 40cm.