[WIP] Supercar chassis with 3 steering modes (Optimized, abandoned)

[BrickbyBrickTechnic]

@Jim's stellar review of the 42056 gave me this idea.

The chassis itself is mostly done, but I wanted to create this topic to get some tips because I am no supercar expert.

Here is the chassis:

It has independent suspension, RWD, 4speed gearbox, and 3 steering modes: front, 4 wheels, crab steering.

Shifting is the interesting part:

-if gear 1 or 2 is selected, 4 wheels steering is selected.

-if gear 3 or 4 is selected, crab steering is selected.

-if no gear is selected, front wheel steering is selected.

This is (at least somewhat) realistic because:

Quote

Fitted as standard, the new rear axle steering with sport tuning combines performance and everyday driveability. An electromechanical adjustment system at each rear wheel enables the steering angle to be adapted based on the current driving situation, steering input and vehicle speed.

The advantage for day-to-day driving: during low-speed maneuvers, the system steers the rear wheels in the opposite direction to that of the front wheels. This has the virtual effect of shortening the wheelbase. The turning circle is reduced to make it easier to park. The advantage for sporty driving: during high-speed maneuvers, the system steers the rear wheels in the same direction as that of the front wheels. Driving stability is increased by the virtual extension of the wheelbase and agility is enhanced by the simultaneous steering of the front and rear axles, especially during overtaking maneuvers on the racetrack.

One of the coolest feature about the real 911 GT3 RS is the fact that it has rear axle steering. It even alternates between steering modes! At low speed it counter steers (to improve the turning radius) and at high speed it steers in the same direction (to increase driving stability). That's so incredibly cool. And it's definitely something we expect to see in The Ultimate supercar TLG is releasing.

6

(From Jim's review)

The gearbox:

So that's what it is. I will post 1 more update before putting this to rest while I wait for parts to arrive. So leave a comment!

BrickbyBrickTechnic

Edited October 21, 2017 by BrickbyBrickTechnic

[Leonardo da Bricki]

Interesting idea, I like the concept. Couple of questions:

1. How much backlash does this system have?

2. Did you use blueprints or a scaling mechanism? Because the engine looks like it is too tall for the car...

Otherwise, cool idea, I like the direction this is heading. Can't wait to see the finished product.

[1gor]

Interesting concept, but I think tires are to small

[Didumos69]

Interesting and ambitious project !

It's hard to comment on the steering without a video showing it's operation. Rear wheel steering as found in the Porsche confines itself to angles that are smaller than angles resulting from LEGO's slack tolerance in steering setups. Therefore it would be interesting to see how much angle the rear wheels make in the different steering modi.

As for the rest of the chassis; the engine sits very high as @Leonardo da Bricki already mentioned. For a supercar I would say you should either place the engine in front of or behind the rear axles or change the push-rod suspension setup to a setup with the springs placed between the upper and lower wishbones, so you can lower the engine.

Edited September 18, 2017 by Didumos69

[Aventador2004]

Meh, it's okay, a little messy, but if it works, that's a different story.

[BrickbyBrickTechnic]

Just now, Aventador2004 said:

Meh, it's okay, a little messy, but if it works, that's a different story.

Of course it works.

[Aventador2004]

Just now, BrickbyBrickTechnic said:

Of course it works.

Works well I meant, with little backlash.

[BrickbyBrickTechnic]

2 hours ago, Aventador2004 said:

Works well I meant, with little backlash.

Oh. Well, in that case it could be better.

7 hours ago, I_Igor said:

Interesting concept, but I think tires are to small

I will be buying some bigger tires.

6 hours ago, Didumos69 said:

It's hard to comment on the steering without a video showing it's operation.

I will post one later today (had some complications yesterday). I'll mention you so you get notified.

 

8 hours ago, Leonardo da Bricki said:

How much backlash does this system have?

2. Did you use blueprints or a scaling mechanism? Because the engine looks like it is too tall for the car...

1. Some, but I think I can remedy it by gearing up the rear steering.

2. No, but I need to replace the engine with a mini v10. It is too big.

6 hours ago, Didumos69 said:

push-rod suspension setup to a setup with the springs placed between the upper and lower wishbones, so you can lower the engine.

I could try, though this may be difficult due to some space constraints. Thanks for the suggestion!

[Aventador2004]

4 hours ago, BrickbyBrickTechnic said:

1. Oh. Well, in that case it could be better.

2. I will be buying some bigger tires.

 

1. Yes, it is bound to happen while using clutch gears.

2. I suggest 68 x 36 zr tires.

[BrickbyBrickTechnic]

1 hour ago, Aventador2004 said:

2. I suggest 68 x 36 zr tires.

Well, we had the same thought, because those are the tires I wish to buy.

EDIT: @Didumos69 here is the video. Hope this explains some stuff.

 

Edited September 18, 2017 by BrickbyBrickTechnic

[Aventador2004]

A bit to much backlash for my taste, it happens due to the clutch gears.

[BrickbyBrickTechnic]

7 minutes ago, Aventador2004 said:

A bit to much backlash for my taste, it happens due to the clutch gears.

Correct. I so far have tried to gear up specifically the rear wheel steering, which seemed to alleviate some of it.

[Aventador2004]

9 minutes ago, BrickbyBrickTechnic said:

Correct. I so far have tried to gear up specifically the rear wheel steering, which seemed to alleviate some of it.

Make a new video too, with different gearing.

[offroadcreations]

Will you be making a body?

And in the video, It appears that the rear wheels don't move in sync with the front ones, but they lag. Is this how it really functions? I think it would be much better if the front and rear steering racks moved proportional to each other, even though the front one moves farther and faster.

[BrickbyBrickTechnic]

6 hours ago, Offroadcreat1ons said:

Will you be making a body?

And in the video, It appears that the rear wheels don't move in sync with the front ones, but they lag. Is this how it really functions? I think it would be much better if the front and rear steering racks moved proportional to each other, even though the front one moves farther and faster.

Yes, I will be making a body.

I think this is due to the backlash created by clutch gears. I have some idea of a solution, so I will try to remedy the lag. It would be better if they move proportionally.

[Appie]

Nice project, looking forward to you solving the backlash puzzle. I tried a similar setup for the Porsche mod I was trying a few months ago and this is exactly the point where the concept stranded. I tried gearing it up as well and even cheating the system by using a clutch gear to re-align wheels, but the end result was still not to my satisfaction. Not to mention the Porsche tyres nulled any advantage I gained from the clutch gear due to their friction on any surface.

Edited September 19, 2017 by Appie

[BrickbyBrickTechnic]

4 hours ago, Appie said:

Not to mention the Porsche tyres nulled any advantage I gained from the clutch gear due to their friction on any surface.

The tires are much more narrow here, so this should be less of a problem.

As for the backlash, I think I have an idea, but can't try it out for a few days.

[mocbuild101]

Interesting idea, but I need to ask the obvious...

What happened to your TC12 entry? Is this the start of it, or have you decided not to enter?

[BrickbyBrickTechnic]

3 hours ago, mocbuild101 said:

What happened to your TC12 entry? Is this the start of it, or have you decided not to enter?

Good question. Either this will be the start of it, or I won't enter. If I do, I'll add some wacky function to it and change the title to "[TC12] Name of entry".

Edit: If this becomes a [TC12] entry, I'll finish the chassis to make sure it works for a generic supercar, and make a full video for it before changing it to TC12.

Edited September 20, 2017 by BrickbyBrickTechnic

[BrickbyBrickTechnic]

UPDATE TIME!

This update mostly concerns the rear suspension and the engine. The engine is lower than before, and its a mini v10. The suspension is harder and more responsive.

As for steering modes, gearing up additionally only added resistance and the rear wheels didn't steer. Adding a clutch on both sides didn't help. I only have 1 more idea, which I will reveal if it works. The front was rebuilt to add durability.

Of course, some outline was also added for scale. Here are some pictures:

So that's it. Leave a comment!

[1gor]

I see some progress, but my verdict will have to wait until you have bigger tires that you wrote about few days ago. The onl thing that is not my cup of tea is engine with axles instead of pistons...

[BrickbyBrickTechnic]

Just now, I_Igor said:

I see some progress, but my verdict will have to wait until you have bigger tires that you wrote about few days ago. The onl thing that is not my cup of tea is engine with axles instead of pistons...

I have yet to purchase these. Unfortunately, an engine with genuine pistons doesn't fit the scale.

[1gor]

20 minutes ago, BrickbyBrickTechnic said:

I have yet to purchase these. Unfortunately, an engine with genuine pistons doesn't fit the scale.

I know about engine scale problem - this was the reason for abandoing few telehandler projects (for now)...

[aminnich]

Are your modeling this after something specifically? I have never seen a super car with different steering modes. 

I like this build, something different. I will be following this :)

[BrickbyBrickTechnic]

11 hours ago, aminnich said:

Are your modeling this after something specifically? I have never seen a super car with different steering modes. 

I like this build, something different. I will be following this :)

Thanks, glad you enjoy!

This isn't based on anything specific, just the quote from Jim's review in the very first post.

@I_Igor I have ordered the tires that come with 42039 (not sure about the exact size). They should fit nicely.