[WIP] Miura concept [FKA Codename Silvestros]

[Jeroen Ottens]

Hi,

I have been working on a new 1:8 scale supercar, codename Silvestros. Here is a first picture of the chassis:

So far it has the following features:

4-wheel drive
4-wheel steering (with positive camber caster & Ackerman geometry)
4-wheel independent pushrod suspension
4D+N+R sequential gearbox
pneumatic diskbrakes on all wheels
V10 fake engine
The steering is dependent on the gear you are in:
R : front wheel steering
1: the wheels steer against each other
4: crabsteering
2-3: proportionally in between

Here is a view from the underside where you can see the linkages needed to control the steering of the wheels:

I plan to include the following features as well:

fancy doors (opening upwards or backwards or whatever as long as it is not regular )
convertible roof
maybe adjustable seats

What I would like your opinion on is the gearbox. As it is now it is a small 4D+N+R gearbox. The good thing about that is that it fits nicely below the low mounted engine (which should give some room for the roof later on) and leaves quite some space between the seats and the rearwheels for mechanisms for the doors, the seats and the .
The bad thing of course is that it is only a 4-speed gearbox, which is a bit lame for a supercar...

So what do you prefer? An 8D+N+R gearbox at the expense of some of the other functionality or keep it as is and fill the space with the other mechanisms?

I am not going to model this car after an existing car, which should give me some freedom with the styling.
And this is not going to be an exclusive model or anything, just a regular buildinginstructions for a small fee kind of project.

Leg godt,

Jeroen
 

Edited December 30, 2018 by Jeroen Ottens

[Leonardo da Bricki]

Already this far on another car?! Nice work! I am very interested in the steering mechanism, would it change/be removed if you added the 8D+N+R gearbox? Because I'd rather have the 4-wheel steering, and the smaller gearbox. And whatever other functions you can jam in there.

[Aventador2004]

leave it how it is, is it very close to the AMG GT R chassis?

[Jeroen Ottens]

12 minutes ago, Leonardo da Bricki said:

Already this far on another car?! Nice work! I am very interested in the steering mechanism, would it change/be removed if you added the 8D+N+R gearbox? Because I'd rather have the 4-wheel steering, and the smaller gearbox. And whatever other functions you can jam in there.

The steering mechanisms would not change, but it would shift from opposite to crab in smaller incremental steps (which actually could be an argument to limit the number of gears, otherwise the effect might be too subtle from gear to gear)

4 minutes ago, Aventador2004 said:

leave it how it is, is it very close to the AMG GT R chassis?

The AMG GT R was in a 1:10 scale, so dimensions are really different. Furthermore in this model the D-N-R switch also influences the steering, in my AMG GT-R it did not.

[TheNextLegoDesinger]

same opinion as @Leonardo da Bricki

[technic_addict]

I look forward to your progress and what kind of supercar you dream up!

[Leewan]

I think you should keep the current gearbox setup and use the available space to add other functions. It already sounds like a fantastic MOC, but I think it would be even better with additional and varied features.

[Didumos69]

Looking very promising! The only thing I don't really like is the engine bed, I personally like to see it more open.

[Aventador2004]

33 minutes ago, Jeroen Ottens said:

The AMG GT R was in a 1:10 scale, so dimensions are really different. Furthermore in this model the D-N-R switch also influences the steering, in my AMG GT-R it did not.

Right, I forgot that.

[tomek9210]

Will you use Porsche wheels?

I'd leave 4 speed gearbox and add some other stuff :)

[Jeroen Ottens]

1 hour ago, Didumos69 said:

Looking very promising! The only thing I don't really like is the engine bed, I personally like to see it more open.

The frame around the engine is still preliminary, I am not happy with it yet (it lacks 'efficiency' so to say). But if I add the convertible roof the engine will be mostly buried under the roof and the lid I think, so in that sense the frame doesn't matter too much.

52 minutes ago, tomek9210 said:

Will you use Porsche wheels?

I'd leave 4 speed gearbox and add some other stuff :)

Yes, I finally came up with a design that fits in the Porsche rims without using the standard LEGO hub.

[1gor]

4 minutes ago, Jeroen Ottens said:

Yes, I finally came up with a design that fits in the Porsche rims without using the standard LEGO hub.

That is best way when car has to be 100% genuine LEGO. Nice progress 

[Erik Leppen]

I like how you used red for all the gearbox and steering stuff, but I still understand nothing of it, even seeing the whole underside. So I'm curious to how this works. Have you built things in the plastic yet to test, or have you just got this digital design? Also, do I understand correct that in 4th gear you can't make turns? (That would a bit weird). Also, what does the rear steering do when the 4+N+R gearbox is in N or R?

What's the steering angle like? And is it correct to assume the part with the gear rack is the front? Concerning the number of gears: personally I couldn't care less whether it's 4 gears or 8 in a Lego model. We get the point either way. So I'd vote for just keeping four. 4+N+R with linked steering is quite an achievement by itself (and actually a function I have tried to do once, but failed badly (but this was before the Claas Xerion set existed)).

The pneumatic brakes are very nice addition. Does it fit within the wheel? Do the pneumatic valves just push the red 5L beam against the inside of the rim, or is there something else going on?

Curious how you will do the styling. Do you have any ideas yet for the color scheme?

[BrickbyBrickTechnic]

Beautiful so far. Following with interest.

[Jeroen Ottens]

2 hours ago, Erik Leppen said:

I like how you used red for all the gearbox and steering stuff, but I still understand nothing of it, even seeing the whole underside. So I'm curious to how this works. Have you built things in the plastic yet to test, or have you just got this digital design? Also, do I understand correct that in 4th gear you can't make turns? (That would a bit weird). Also, what does the rear steering do when the 4+N+R gearbox is in N or R?

What's the steering angle like? And is it correct to assume the part with the gear rack is the front? Concerning the number of gears: personally I couldn't care less whether it's 4 gears or 8 in a Lego model. We get the point either way. So I'd vote for just keeping four. 4+N+R with linked steering is quite an achievement by itself (and actually a function I have tried to do once, but failed badly (but this was before the Claas Xerion set existed)).

The pneumatic brakes are very nice addition. Does it fit within the wheel? Do the pneumatic valves just push the red 5L beam against the inside of the rim, or is there something else going on?

Curious how you will do the styling. Do you have any ideas yet for the color scheme?

I have build it in the flesh and it works smoothly (especially without wheels, I still have to test it with wheels and the added friction that that will give)
In 4th gear you will get crabsteering, in reverse the rear steering is locked, so you have just normal 2 wheel steering. When in neutral the front wheels steer normally and the rear wheel steer at half the amplitude of the gear-dependent steering (if that makes any sense). But since you normally can't drive a car in neutral I don't bother about it.
The steering angle is not too brilliant due to the positive camber. These suspension setups with positive camber and a gearrack behind the wheels are always a fight between sufficiently small travel, sufficiently large steeringlock, form-locked wishbones and an as symmetric as possible structure to lead the suspensionforces through. The gearrack in front of the frontwheels is actually part of the gear-dependent steeringmode selector (in fact almost everything in front of the front wheels is the gear dependent steeringmode selector.
The pneumatic brakes fit nicely in the wheel, they brake on the sprocketwheels, not on the inside of the wheel.

I really want to use dark azure for the bodywork now that almost all the panels are available. But, not having any flexaxles will likely mean that I will use a secondary colour as well. Maybe a Chiron-like blue/black/silver scheme...

As for styling I really want to try to have a more open styling this time, with holes and gaps to show the inner workings, but usually I start adding panels together and before I know it I have some large closed surfaces and then it becomes tempting to close everything

[Leonardo da Bricki]

2 minutes ago, Jeroen Ottens said:

I really want to use dark azure for the bodywork now that almost all the panels are available. But, not having any flexaxles will likely mean that I will use a secondary colour as well. Maybe a Chiron-like blue/black/silver scheme...

That sounds like it would look awesome. Would you do the front blue, or the back blue? Front is traditional, but with no flex axles, it might be hard, depending on the style.

[tomek9210]

Why camber and not caster and kingpin inclination? It could help the steering to straighten the wheels after turning.

[Jeroen Ottens]

16 minutes ago, tomek9210 said:

Why camber and not caster and kingpin inclination? It could help the steering to straighten the wheels after turning.

You are right, I mixed up the terms (again). The steering has positive caster, not camber

Kingpin inclination would make the steeringsetup even more complicated (read less robust). The steering point is still within the wheel (albeit not at the center), so adding kingpin inclination would not help too much for minimizing the space around the wheels when steered.

[technic_addict]

16 hours ago, Jeroen Ottens said:

 

I really want to use dark azure for the bodywork now that almost all the panels are available. But, not having any flexaxles will likely mean that I will use a secondary colour as well. Maybe a Chiron-like blue/black/silver scheme...

I would  a closed supercar in medium blue or dark azure.  I have made a spreadsheet of all Technic parts in both colours and it will be a challenge.  Both colours are lacking in certain areas.  Dark azure has more panels.  Medium blue has more connectors.

I look forward to the final results.

[grego18f]

As @Erik Leppen mentioned, having a 8 speed gearbox is not that necessary due to the steering mechanism. And I would say 4 speeds are better in comparison with 8 because the difference in gear ratios between the first and the last speed is smaller, causing less friction…

The color scheme you have chosen will make the car even more special

I look forward to seeing the end result!

 

[KD123]

I am really interested in seeing how your pneumatic brakes develop.    What do you think about using a part like 45590 (rubber double connector) like a breakpad?

Following with great interest.

[Jeroen Ottens]

34 minutes ago, KD123 said:

I am really interested in seeing how your pneumatic brakes develop.    What do you think about using a part like 45590 (rubber double connector) like a breakpad?

Following with great interest.

The brakes are finished as they are now I think. I have tried to incorporate the rubber double connector, but I couldn't find the space for it. I may add some parts for aesthetics though, as it is now you can see the red 5L beam through the spokes, but since it is sideways you can't really see the colour pop out.

[Rudivdk]

Looking impressive so far...

Few questions out of interest:

How do you plan on controlling the gears, D-N-R selector on center console and paddle shifters at steering column for gear change? Or all from single shifter (I see only 1 shifter in center console...)

And how will you control the brakes? Mini-pump under foot pedal would be awesome (but not very playable I think). Or an air tank and the valve attached to foot pedal with spring for auto release...

I would love to see dark azure bodywork, seems like a very good color to work with.  I am designing my current MOC in such a way that it should be buildable in dark azure as well, but having a secondary/contrast color is mandatory given the available parts (I chose red on mine).

Will be following this one for sure

[steph77]

Hi Jeroen,

Good jo until now. For the gearbox I would personally keep it simple and get place for other functions. I am sure your creativity will find a way to use this extra space

 

 

[Jeroen Ottens]

13 hours ago, Rudivdk said:

Looking impressive so far...

Few questions out of interest:

How do you plan on controlling the gears, D-N-R selector on center console and paddle shifters at steering column for gear change? Or all from single shifter (I see only 1 shifter in center console...)

And how will you control the brakes? Mini-pump under foot pedal would be awesome (but not very playable I think). Or an air tank and the valve attached to foot pedal with spring for auto release...

I would love to see dark azure bodywork, seems like a very good color to work with.  I am designing my current MOC in such a way that it should be buildable in dark azure as well, but having a secondary/contrast color is mandatory given the available parts (I chose red on mine).

Will be following this one for sure

Thanks
The center column shifter is the D-N-R switch. I haven't decided yet on the sequential shifter. I will at least have some HoG shifter (a gear, or a lever) and maybe I will add paddleshifters as well. The latter will depend on the space near the steeringcolumn, which depends on the answer to your second question...

For the brake control I do not have a clear picture in my head yet. Having a brakepedal is more authentic, but in terms of play-value pretty shitty because of the location. I am not sure if one stroke of a minipump is enough to engage the brakes, definitely going to test that though, because that would be an elegant solution. I like the idea of using the volume of the pump to increase the pressure in the system. If a minipump is too small I can also try the big pump (it probably will become a HoG brake then)
The alternative is indeed an airtank and a switch. But the airtanks are rare, bulky and expensive and the switch has a lot of friction which means it will be difficult to let it return automatically, so that is not my preferred solution

I am looking forward to your model, very interested what you come up with in terms of bodywork. In terms of inspiration I have three styles that I am toying with in my head: The tough, masculine lines of the Audi R8, the angled, sharp surfaces of the Lamborghini Aventador or the curved, open bodywork of the McLaren Senna. Very different styles... so choices are needed at some point