[WIP] Jaguar XJR19 Le Mans Prototype concept

[Erik Leppen]

Ever since set 42039 hit the shelves, I feel attracted to building Le Mans prototype cars, due to their characteristic shape and almost futuristic looks. So I think you can imagine the delight I felt when during my random stroll on the interwebs a few months back, I stumbled upon the following concept car.

Back then, I tried building a Lego version of it and got quite far. But due to lack of pieces I had to abandon early. I have since bricklinked a thing or two and want to redo the model from scratch.

I think the actual car doesn't even exist in reality yet, and I think this is actually a rendered image. If I remember correctly, it is a concept that they want to try to build in reality in 2020. Personally I think it's the least car-like looking car there is (if you only count serious car models). If you forget the wheels and decals, it could be modern architecture as well. What's also cool is how the black wheel arches are actually almost shaped like Technic panels.

I will be using the wheels of 8070, 42039 et al. These are slightly less than 9 studs in diameter, which justifies the following side view:

The planned functions are:

• front steering
• rear drive, driving a fake engine
• suspension
• doors (powered by the damped springs also used in 8448)

There's little space, so I don't count on having a gearbox. With a bit of luck, I can find room for a 2-speed, which at least gives the idea of a gearbox. But it probably won't be a proper "supercar" in the Lego sense of the word. We'll see, and I might need some help from you guys with this later on.

OK, let's start. All I have so far is the two suspension modules. Here's the front suspension:

First thing you might notice is, I'm using the long wishbone arms. Personally this is what makes the suspension much more interesting to myself, because it's more challenging to make it work and looks much more like F1-type suspension. Also you see I'm using only 1 small spring per wheel. The suspension travel is very little (about 1 stud) so I hope having 1 spring per axle is enough. It'll have to be though, because the mechanism isn't very strong, so a stronger spring will result in parts coming loose.

The black axle on the left is the steering input, to that's where the rest of the car will come. Thanks to the pins with pin hole, the 5x7 frame is pretty rigidly attached to the whole thing. The chassis will be connected to that 5x7 frame.

The rear suspension is unsteered, and therefore less spectacular. But it holds the differential:

Those two modules is where I am right now. I do want to have said beforehand that I'm really not good at recreating existing car bodies, so it will be difficult and I will take some slack here and there. But how fortunate is it, that Lego has the perfect color for this car.

Older Technic fans know these panels from the great Offroader 8466 and its smaller brother 8465. I'm actually not even a fan of the old panels, but this car is really the perfect opportunity to put them to use (and indeed, I bricklinked some, so I have a nice collection of them). Unfortunately though, these four pairs of panels are the only pieces in this color (except a very rare ribbed hose I don't have). So the body will necessarily be a bit crude. A body with modern pieces would probably be better, but I want to see how far I can come using these good old panels. When we get there, your feedback will be very welcome. The gaps will be filled up with black, I think. But a word of warning: I will probably add some details in a second color, simply because I find black a bit boring to work with.

OK, that's it for the opening post. I hope you don't mind all the rambling I do between the pics. Next up will be a basic chassis connecting the two modules together at the right distance.

[Lakop]

Now thats a challenge. Body work will be the biggest hurdle, something i'm practising at the moment. I like what you've done so far. It all looks very compact, I will watch with interest.

H

[BrickbyBrickTechnic]

I look forward to some more progress because this is shaping up to be awesome already. Following with interest.

[1gor]

Front suspension is very good, since LMP cars have bery similar suspension to F1, and "H" frame gives nice posibilities to attach it to monocoque. Very good start 

[Erik Leppen]

New progress!

The color of the seat may not be to everyone's taste but it's a way to deviate from black-only. The two handles on the sides with the yellow axles have no purpose yet. Also, it's not rigid enough yet, so the connection to the 5x7 frame will have to be rebuilt, but at least the door mechanism is in place.

Here's the same mechanism when it's opened. (Left and right are independent)

[tomek9210]

Nice progress.

Use axles with stop to connect wheels, because they may fall off with current configuration.

[Erik Leppen]

3 hours ago, tomek9210 said:

Use axles with stop to connect wheels, because they may fall off with current configuration.

Yes, I will. But the axles fall out so long as the wheels are not on, so I use this as a placeholder.

[1gor]

Color of seat could associate on dynamic nature of this vehicle

[9 fingers]

Wery interesting car. I like that you will build it with old panels. Cant wait to see the end result. 

[AkiyamaWataru]

@Erik Leppen I foubd an issue with your seating position. If it is going to be a lmp-race car, the seat should be set a bit to the right or left. The regulations for this race car state the theoretical possibility to transport a second human in the cabin must be given. It has been a discussion on 42039 as well.

[Erik Leppen]

Technically, you're right @AkiyamaWataru. But I think I will keep the seat centered for several reasons. First of all, there's no room. Off-centering the seat would require spaced needed to enforce the chassis. Second, off-centering the seat would make the cabin wider. You see the effect of this in set 42039. Third, I find "theoretical room for a second person" not enough of a function in a Lego model. Fourth, the seat isn't realistic anyway, because there's already too little leg room. So yeah, I think the model would be better off with a centered seat, even though that would not be conform official Le Mans regulations.

The only reason to off-center the seat would be that I could use the space on the free side for a gearbox.

[AkiyamaWataru]

@Erik Leppen good I just wanted to raise this thought before, this change is to late and you think of could have beens :) All your points are valid and inside an LMP this room has a function for wiring, control units and fire extinguishig equipment.

[Aventador2004]

1 hour ago, Erik Leppen said:

... @AkiyamaWataru

The only reason to off-center the seat would be that I could use the space on the free side for a gearbox.

What they put in the passenger seat is the battery, it offsets driver weight. The 42039 did not have room to do that, with a huge seat.

[Erik Leppen]

I have progress!

I have added the engine (as low as possible). Also, I added a steering wheel for the driver. But the most important thing in this update is that I joined the front and rear modules I had into one and determined the length. It's going to be pretty long, in relation to other cars using the same wheels. But it's in scale with the image.

The engine is not connected to the rear wheels yet. I did move the drive axle further up, it now goes over the diff instead of under, because this way I can move the engine one stud lower.

What's most interesting is that there's a large empty spot between the engine and the seat. As you can see here, it's six studs.

So that might be enough to put a simple gearbox in between. The two yellow axles with axle joiners could be used to control the changeover catches. They probably won't be linked though, so you need to disengage one manually if you want to use the other. What I'm hoping for is to fit a 4-speed, with the left lever controlling gears 1 and 2 and the right lever controlling gears 3 and 4.

You also see three blue pins above the engine, that can be used to form a nice closed frame that hopefully makes things rigid and strong.

As a precaution, I changed the way the steering HOG is connected. I now used U-joints instead of a gear system. This uses much less space, as the axle now fits closely beneath the seat. The downside is that the HOG is currently turning the wrong way, but I have already found a spot closer toe the front axle where two 8t gears should fit to reverse the rotation, without flipping the steering wheel (which turns the correct way now).

This is the underside view. I replaced the rear suspension's 5x11 frame by a 5x7 because the engine block is in the way. If you follow the HOG axle you see a CV joint. That section of the axle can be replaced by two 8t gears.

[Lox Lego]

Wow, this looks fantastic. the structure is so compact with cool functions. I look forward to seeing the doors in action. I will follow this post! Thanks for sharing. 

[Aleh]

Looks professionsl 

And the choice of colours is very original! 

[1gor]

Very nice development. Chassis looks really good 

[Erik Leppen]

Update!

For take 4, I have added two important things:

• Wheel arches
• Gearbox

I'm really happy I got the gearbox in. It has 4 speeds. I had to rebuild the switchers because the first version of the gearbox was Porsche style: the gears were in the wrong order. (left up 2, left down 1, right up 4, right down 3). I realized I could fix this by mirroring the whole gearbox, but that was not possible. So I changed the switchers, so that moving the switcher up makes the driving ring go down. As an added bonus, I could use a 4x6 beam for the switch handle, a part that exists in purple.

The gears are pretty close together in ratio though. Each gear is 20/16 times the previous one. So the four gears are approximately 1 : 1.25 : 1.55 : 2. Personally, I like how the ratios form an exact exponential sequence. There is no way to prevent engaging the left and right driving ring at once, which will jam the system. I think there's no way around this.

The gearbox is tightly fit into a frame consisting of mostly half-width beams, which makes it difficult to build and fit in, but I love this way of building because it can be so compact. I used the old 2L driving rings and dark-gray 16t clutch gears (the red 16t gears are just freewheeling on fixed axles).

I also fitted some wheels on.

What do you think about the yellow rims? I can try black ones too next time. It remains to be seen which color would be the best fit.

The wheel arches look very big, but this is I think the smallest possible, because there has to be room for the suspension and steering, and I wanted them to be the same front and back. The way the wheel arches are attached is temporary, and needs to be reinforced somehow later.

What I also changed, but you might not see it immediately, is, I reinforced the part of the chassis right behind the front suspension (the vertical 5x7 frame) and inverted the direction of the HOG by adding two 8t gears (see the yellow 9L axle). This section will be quite nightmarish for the instructions though. Speaking of which, I'm keeping a (new) digital file, and want to say in advanced that the build will not be modular. It's difficult enough as it is already. :)

OK, so this is the last update before starting with the panels. Next update will focus more on the body and will have some green, at last :)

Edited November 30, 2017 by Erik Leppen

[agrof]

Looks very good so far, super flat chassis. I especially like the axles, very very compact in this scale. 

I vote for black rims (I always do), but if it is possible, I would add some brick built brakes (yellow/red) to the wheel hubs. It would be a nice detail.

[ginger-snapped]

I can't wait for the final product. The suspension and chassis are very impressive. Keep up the good work and good luck!

[Aleh]

Cool! I wonder how front suspencion works  

[Erik Leppen]

On ‎25‎-‎11‎-‎2017 at 5:30 PM, Aleh said:

I wonder how front suspencion works  

It's very similar to several Formula 1 car sets, like 42000 or 8458; where a 9L link acts as a pushrod. I only changed the lengths of the various levers to decrease the suspension travel and make it possible to use a softer spring. Here are two renders using color coded parts for easy legibility:

The idea is that the wishbones form a parallellogram that can be deformed. Gravity pushes the center down, or, the wheel hubs up. This will push the dioagonal pushrod inwards, which is connected with a towball-pin to thethat rotates around a vertical axle (see the yellow connector). This in turn compresses the spring. (or, reversely, the spring pushes the wheel hubs down to hold the car up.)

Anyhow, there's new progress!

I think @agrof is correct that black rims work better here. Makes it much more "serious". I do realize black is a difficult color to photograph, so I hope things are clear. I only have a tablet to take the pictures, and I wait for daylight to take them. The reason I put the rims "backwards" is that on the rear axle, I used the CV joints which have only one stud of axle useable, and the wheel rims have an axle hole only on the outside, so the rear wheels need to be outside-facing-inwards. So I put the front wheels the same way.

I added a lot of black panels in the central section, and I added the first green panels around the suspensions.

In an all-black build, the blue pins look a bit messy, so I might try to find a way to use black pins there.

I also took a really low picture showing the ground clearance and the shape of the roof. Yes, there is a beam in the middle of the windscreen. The reason is to add the necessary rigidity (That's also why the front of the roof is shaped this way. This way, it's a rigid structure, minimizing the amount of flex (at least vertically. The torsional flex is very hard to beat in studless Technic). The gray frame on the side will be covered by a tile.

Edited November 29, 2017 by Erik Leppen

[Aleh]

Just now, Erik Leppen said:

It's very similar to several Formula 1 car sets, like 42000 or 8458; where a 9L link acts as a pushrod. I only changed the lengths of the various levers to decrease the suspension travel and make it possible to use a softer spring. Here are two renders using color coded parts for easy legibility:

The idea is that the wishbones form a parallellogram that can be deformed. Gravity pushes the center down, or, the wheel hubs up. This will push the dioagonal pushrod inwards, which is connected with a towball-pin to thethat rotates around a vertical axle (see the yellow connector). This in turn compresses the spring. (or, reversely, the spring pushes the wheel hubs down to hold the car up.)

 

 

Oh, thanks for explaining!

[1gor]

Jag is taking shape, really nice. I also prefer black rims

[Aventador2004]

Good progress, but could you fix the pics so they center. The one picture goes halfway off the page.