[WIP] Ferrari 125s in 1:8 scale

[Divitis]

With only these 1, 2 and 3 (arguably) Technic creations built in the last 8 years and less than a handful of sets assembled meanwhile, last December I abruptly decided to MOC the Ferrari 125s - the first Ferrari ever built, and one apparently never attempted before in LEGO in any scale before - and to do so without cutting any corners.

Which means: a high fidelity replica of how things both work and look in a sturdy, smooth working, 100% legal way. And also motorized, since I'm at it.

Why? At the risk of making enemies: too many celebrated 1:8 models I saw around here and Rebrickable seem like nothing more than a generic copy-paste chassis covered up in some lazy paneling that falls shorts of the angles and curves of the original. And one can only think 'I could do better' that many times before wanting to challenge that thought.  

 

Today, after a rollercoaster of achievements and compromises, I decided I'd start a production diary that will hopefully also be helpful those crazy enough thinking of wasting some hundreds of hours on a similar project.

But enough with the intro and into the nuts and bolts of it. 

1. References - circa 15th December.

This is what the official Ferrari page says about this barchetta. Of course I intend to replicate it all.

Also this technical drawing came up. The source is unknown, but seems legit, and it immediately proved hugely helpful.

At first my eyes were on the rear axle: combining both shock absorbers and leaf springs seemed like the kind of overengineering I was bargaining for. But then, as I had to look up pretty much on the list, the steering system proved the most immediate challenge that needed solving.

 

I promise to include the first WIP in the next post. Meanwhile, questions are very welcome. Also sharing your honest opinion on my chances of success is highly encouraged! it's important to know where one's ambition stands against reality. 

Edited June 27, 2024 by Divitis
Linked images

[langko]

12 minutes ago, Divitis said:

sharing your honest opinion on my chances of success is highly encouraged!

The more time you are willing to put into the model the higher your chances of success will be. You will undoubtedly have failures along the journey, but it’s about how willing you are to persevere and find a solution. 
I spent 18 months on my first 1:8 scale MOC… only to pull it all apart again afterwards and spend another year redesigning nearly all of it from scratch…
Not saying it will take that long for you, but don’t be disappointed if the project takes longer than you expected. It’s worth it in the end. Good luck 

[Paul B Technic]

Good luck, I look forward to seeing your progress.

[1gor]

The only real problem in my eyes is how to replicate elegant lines of this  Carrozzeria Touring Superleggera barchetta bodywork. 

(Front radiator grille is relativelly simple - very boxy solution in comparisson to later Touring and specially Vignale masterpieces)

[Stereo]

I suppose I'm first curious about the wheel/tire, 5.00-15 should be about 57cm tall, 15cm wide, or 71x19mm in 1:8.  And Lego Technic for the most part jumps from 62.4x20 (large truck/crane) at kinda reasonable size to the very wide (for something like this) medium wheels with 68/82mm tires.

Maybe Vespa 75x20 tires work?  Ignoring that they have motorcycle profile.  I'd probably scale off of those (1:7.5) or the 'truck' tires (1:9).

Edited June 28, 2024 by Stereo

[Divitis]

2. Wheels and Gearbox - circa 16th December

This is a screenshot from the first .io file. It looks like I had a decent 2 views template already in place for scaling. (the front view is hidden here).

The spec sheet reports that the real car has bigger tires at the rear than at the front. So I purchased 4 Vespa tires (which at 1:8 scale fall in between front and rear, I think) and 2 x 81.6mm tires to see how'd they look at the rear. Maybe the extra width will not be noticeable given how tight the wheel arcs are?

Btw, I wish I had @Stereo's proficiency with doing the math needed btw. I had to ask chat GPT for clarification as 5.00-15 meant nothing to me at the time and a calculator isn't easily available on the web.

 

I'm working with a 3 studs high chassis, which gives enough space for this gearbox configuration.

The gearbox should:

• be manual
• transmit power (see the 2 L motors coupled through a differential) to the wheels
• have realistic separation between gears (another thing I see too often overlooked) including the R being slower that the 1st. This is especially challenging here because the 5th and R sit on the same ring.

haven't seen before anyone using a ball join for the movement of the stick. It'll be still a while before I am to build the first prototype, but I can report - Spoiler alert! -  it's a pleasantly realistic feeling to operate it. Recommended!

I also like the idea of system bricks for the bracing, gives off an old Lego vibe that I think matches the age of the real car.

 

To your points:

23 hours ago, langko said:

You will undoubtedly have failures along the journey, but it’s about how willing you are to persevere and find a solution. 

Of course you are right. However, I am not a prolific builder. I build and rebuild and perfect one project to the point of exhaustion until I am convinced that I have given it all and didn't overlook anything. I would also drop a project if I don't think I can make it happen to the level I had committed to. Probably doesn't for the best learning curve...

 

20 hours ago, 1gor said:

The only real problem in my eyes is how to replicate elegant lines of this  Carrozzeria Touring Superleggera barchetta bodywork.

I recall thinking in a moment of sanity: Why T. F. did I pick the curviest car ever?

And even considering - not sure if already three days into the build but soon enough - to only do the chassis and then give it to the community to finish things off.

 

 

Next up, something you might have heard me talking about before: worm and sector steering. 

[Stereo]

It's kinda specialist info, cause tire sizes before ~1965 didn't work the same way as modern ones.  5 means the width of the tread, 15 is the diameter of wheel it fits onto.  Unlike modern tires there's no measuring the height of the tire sidewall, it's just assumed to be a similar ratio to other wheels (about 75% the width).  So in modern terms it should be a 125/75r15 tire on the front, 155/75r15 on the rear.  But only approximately.  If you have a properly scaled side view it's better to measure off of that.

Edited June 28, 2024 by Stereo

[1gor]

Well, perhaps uou needed challemge, but one thing is certain - you have style

[Divitis]

2. Worm and sector steering - circa 17th December

I must have been working every waking hour in those first days, because the steering system is already present in the first Stud.io file - for reference, I am currently at version 107. 

I already presented worm and sector steering here: Worm and sector steering - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums and in a more advanced state. So I will only talk about this early implementation.

In a nutshell, worm and sector works like this: The worm screw moves the black box, to which the white gear rack in attached. The rack rotates the dark gray 8t gear and consequently the red liftarms. 
Eventually, I will learn which factors introduce play in the mechanism, and work to counter them.
- The 8t gear itself. A 16t or 24t gear meshes more robustly with the rack.
- The length of the red arm also amplifies of any slack or play. So one will want to shorten it as much as possible.

To make things worst, I don't even own the worm screw yet; so I have no way of determining how many revolutions are required to steer and the range of movement of the black cube. Eventually, I'll be watching videos frame by frame to figure out while the order arrived. 

Finally, the angular motor seemed like a good choice not only because I have two gathering dust in my drawers, but the double output would simplify making the steering wheel work (another must, of course).

 

To your points:

On 6/29/2024 at 5:01 AM, 1gor said:

Well, perhaps uou needed challemge, but one thing is certain - you have style

I think you mean to say: Clearly you bit more than you can chew, but at least chose a real looking car.

Well, I dare to say: stay tuned. Lots changes in 106 iterations. 

 

 

Next up: the V12 60° engine. 

Edited June 30, 2024 by Divitis

[1gor]

V8? This will be a kind of restomod (since it had V12 engine)?

[Divitis]

4 minutes ago, 1gor said:

V8? This will be a kind of restomod (since it had V12 engine)?

Of course, and well spotted!

V12 60° of course. Just as Gioacchino Colombo designed it.

Apologies , I was typing in a rush, the original post is now amended.

[Timewhatistime]

Maybe these videos can be helpful:

 

Moreover, I'm pretty sure it's possible to determine how many revolutions are required to steer and the range of movement of the black cube by looking carefully at images or stud.io renders.

My guess is that one revolutions equals a movement of 3L or 4L.

And even more sure: There will be some EB-members who own the 6L worm gear and know the answer...  :-)

 

 

[1gor]

2 hours ago, Divitis said:

Of course, and well spotted!

V12 60° of course. Just as Gioacchino Colombo designed it.

 

Yes, he constructed small block engines and Aurelio Lampredi made big block engines (usually for La Carrera PanAmericana)

[Stereo]

5 hours ago, Timewhatistime said:

My guess is that one revolutions equals a movement of 3L or 4L.

Yes, it has 4 teeth and they're spaced 1 stud apart lengthwise, so one revolution is 4L (moves the black box from one end to the other, since it's 2 studs long).  The other kind of gear rack is 5 teeth per 2 studs, so 4L is 10 gear teeth per revolution.  So on a 20t gear it would turn 180 degrees.  I imagine in that design you don't need more than 60 degrees on the red arm.

Edited June 30, 2024 by Stereo

[Divitis]

3. Engine, General blocking, leaf spring suspensions  - circa 20th December

v2 of the wip Stud.io file shows a lot of progress, let's go in order.

Engine
If there is one thing that screams 'sloppy' to me in both MOCs and sets is the engine angle, which is as important to its performance as the wheelbase is to the general handling of a car. So to not copy it, space allowing, is inexcusable.
And yet, this piece is in vogue.  

Here you can see my attempt at a true 60 degrees setup, which required a change in motor.

 

General blocking and relative size

There is barely enough space for the hub in the back!

I started this project thinking that in a 1:8 model I would have all the space in the world and more. Turns out, not quite.
The 125s is a very tiny car, especially by today's standards. You can see it racing along the LaFerrari in the video below to get the idea.

 

Leaf springs suspension

This is another area where I think I'm innovating after worm and sector steering; I haven't seen anyone using the wishbone piece before - happy to be proven wrong of course 
I had the idea early on but since I wanted to make sure it is -legally- intended to bend. After checking all its usages on BL, I got my answer. It is at least in set 7002!

On the right, the alternative tire I'm considering.

As usual, I'm using a piece I don't own - the Vespa tire - and couldn't even find the right wheel hub in Studio so I put that in as a placeholder. A choice I'll pay a price for, eventually. 

 

To your points:

11 hours ago, Timewhatistime said:

My guess is that one revolutions equals a movement of 3L or 4L.

And even more sure: There will be some EB-members who own the 6L worm gear and know the answer...  :-)

5 hours ago, Stereo said:

Yes, it has 4 teeth and they're spaced 1 stud apart lengthwise, so one revolution is 4L

Thank you! I reckon back then I was too shy on this forum to just bomb everyone with questions. Now it's all figured out.

 

Next up: Caster angle

Edited June 30, 2024 by Divitis

[Timewhatistime]

This is the right occasion to ask a question which has been bothering me for a long time.

I'm sure, here are the experts to answer it!

The steering is - as everything else in this MOC - very realistic. But what's exactly the point in converting a rotation into a movement (by 6L worm gear and black counterpart) and then in turn converting it back to a rotation (by 4L gear rack and 8T gear)?

Wouldn't it be easier to use a bunch of gears or maybe a cardan or a chain or whatever? Everything seems to be easier than a two-fold sliding mechanism, which needs bracing, lube, and which consists of many moving parts which can hardly be protected against dirt or moisture?

What is the advantage of this mechanism? (It must be a big advantage, I believe, because it wins the trade-off with the alternative solutions...)

Edited June 30, 2024 by Timewhatistime

[Paul B Technic]

You are making great progress with this :)

 

[Stereo]

35 minutes ago, Timewhatistime said:

Wouldn't it be easier to use a bunch of gears or maybe a cardan or a chain or whatever? Everything seems to be easier than a two-fold sliding mechanism, which needs bracing, lube, and which consists of many moving parts which can hardly be protected against dirt or moisture?

Lubrication/durability seems to be most of the answer, the worm gear is desirable for its high reduction ratio (remember this was invented well before power steering so 20:1, 30:1 ratios aren't uncommon) but because the teeth slide against each other, it uses ball bearings for the worm in a sealed compartment, and then the other rack acting on the Pitman arm is just a simple motion with much less sliding.

 

Might be a  bit of a factor of hand building vs. mass production as well, rack & pinion gears need a whole bunch of teeth cut into the rack, this seems to get by with fewer.  Like a rack and pinion might have a 10 tooth pinion and 60 on the rack to get the same kind of ratio.

Edited June 30, 2024 by Stereo

[2GodBDGlory]

I LOVE the ambition of this model! Unique/realistic engineering solutions are what make me excited about models, so I love seeing the worm-and-sector steering and the 60 degree V12! The ball joint for the shifter is a neat idea, but I worry about how high the joint is above the gearbox. It seems like you'll need a really long lever on top of it to regain your mechanical advantage to shift properly! (Though you hint that it's working, so I'll reserve judgment). The leaf spring idea is also nice! I bought a few of those parts not too long ago, but haven't found a need for them yet. This looks like a nice one, especially since you can add a spring to add stiffness while still being reasonably realistic.

I do question whether the studded bracing for the gearbox will hold up in practice, though. 1:8 cars take a lot of effort to drive, and adding a complex gearbox like that requires a lot more force, making any weak points very susceptible to problems. I do love the willingness to use some wild half-stud offsets in there, though! I'd recommend giving that some real-world tests before you get too far, though even then without having the full weight of the model it might be deceptive. I hope it works out well, though!

[Divitis]

4. Caster angle  - circa 21th December

Version 3 of the Stud.io file introduces caster angle.

By this time I am avidly consuming this forum, and caster angle comes up a lot. I also remember reading in Sariel's book something along the lines of 'It's considered a great display of skills among builders to include...'. So I naturally want it. 

And after reading that a positive caster angle was firstly proposed in 1896, it seemed legitimate to imagine the 125s had it.

For the implementation, I have to give credit to an unknown user of this forum - please do credit yourself - who thought of simply offsetting the suspension arms, rather than inclining the whole forward section of the car.

The bracing is still non-existent, but already the motors configuration has changes substantially. I don't advice you trying to keep track. (This is still file 3 out of 107) 

I was apparently also toying with some other solutions such as the one below, but they were short lived and never made it to the 'main' model.

After much reading and looking at the car schematic (first post) it seems like the shock absorber is mounted perpendicular to the ground, so the first solution is the more accurate one.

 

To your points:
 

22 hours ago, Timewhatistime said:

What is the advantage of this mechanism? (It must be a big advantage, I believe, because it wins the trade-off with the alternative solutions...)

 

22 hours ago, Stereo said:

Lubrication/durability seems to be most of the answer, the worm gear is desirable for its high reduction ratio (remember this was invented well before power steering so 20:1, 30:1 ratios aren't uncommon) but because the teeth slide against each other, it uses ball bearings for the worm in a sealed compartment, and then the other rack acting on the Pitman arm is just a simple motion with much less sliding.

 

Might be a  bit of a factor of hand building vs. mass production as well, rack & pinion gears need a whole bunch of teeth cut into the rack, this seems to get by with fewer.  Like a rack and pinion might have a 10 tooth pinion and 60 on the rack to get the same kind of ratio.

These are an excellent observations!
What I also read is that with this set-up, if a wheel hits a bump, the vibration doesn't reach the steering wheel,becasue the worm screw cannot be backdriven. Admitdelly, the Lego one can, so this advantage is negated here.

 

10 hours ago, 2GodBDGlory said:

The ball joint for the shifter is a neat idea, but I worry about how high the joint is above the gearbox. It seems like you'll need a really long lever on top of it to regain your mechanical advantage to shift properly!

The biggest limitation I found is the range of movement of the ball joint, which is not as ample as one might think.

So one has to 'multiply' it by using a long stick (from the ball joint to the driving rings).
Other than that, it's mostly about fixing the joint holder properly.

 

10 hours ago, 2GodBDGlory said:

I do question whether the studded bracing for the gearbox will hold up in practice, though. 1:8 cars take a lot of effort to drive, and adding a complex gearbox like that requires a lot more force, making any weak points very susceptible to problems.

You're absolutely right. However at this point in time I still know next to nothing about the forces that come to play as this is the first car with a gearbox that I design.

 

10 hours ago, 2GodBDGlory said:

The leaf spring idea is also nice! I bought a few of those parts not too long ago, but haven't found a need for them yet. This looks like a nice one, especially since you can add a spring to add stiffness while still being reasonably realistic.

Thank you! I am quite proud of it actually. The only disadvantage is that the part is rather long, so probably out of scale in most models, including this one.

An alternative solution I explored in real life was this one:

 + 

But the lack of connection points and excessive softness made me scrap it. Could be interesting for a smaller scale model though.

 

Next up: Connecting the fake engine and steering, choosing wheel arches and general bracing.

[Timewhatistime]

Oh yes, the property to absorb bumps and to prevent the steering wheel (and the driver) from vibrations is a very convincing aspect of the steering setup with a worm gear. Thank you very much for mentioning this!

[Paul B Technic]

Wow, you are making great progress. I love the level of detail in this.

[Divitis]

5. Connections and wheel arches  - circa 22th December

A lot of gears are needed to transfer motion from the gearbox to the V12 (and also from the steering motor to the wheel). This is the biggest drawback of these early designs.

I decided to work on the chassis and the bodywork separately. Breaking this monumental - at least for me - project in two seems the only feasible way to be able to make it.

So, some blueprinting is going on, to understand how to distribute the available space in a way that won't come back to bite me in the butt later on, even if it means facing harsh constraints for the mechanics right now. In hindsight, this is probably the best decision I took in these early stages.

The orange axle represents the tapering of the hood.

I also wanted to define key aesthetic pieces early on. Again, to make sure there's enough space for them. The 13 long wheel arc immediately looked like the obvious choice, despite the odd connection points.

 

To your points:

On 7/2/2024 at 2:42 AM, Paul B Technic said:

Wow, you are making great progress. I love the level of detail in this.

Thank you for your continue support, it means a lot. And speaking of details, believe me, my hands are hitching to show you what's lying on my desk now. 

 

Next up: Fast forward through the evolution of the front axle and the self imposed rule of  ±30 degrees of steering. 

[2GodBDGlory]

I'm enjoying your serialized presentation of the model's development! It must be a lot more work for you to type so many updates, but it's fun to see a sort of WIP thread without the long waits between updates you'd have in a normal situation

[NV Lego technic]

From my experience, it's much quicker and kind of fun to write updates.