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[MOC] Koenigsegg Jesko Drivetrain

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This model is the start of a potential series of drivetrain models. The idea for this came from the original Koenigsegg Jesko's unique transmission design. Between the transmission and several other notable features, I had considered building a full 1:8 scale Jesko model, but I'm still hesitant to spend much time on bodywork that could be spent building interesting mechanical features. Eventually, the idea struck to build a sort of display model showcasing the drivetrain of this car, but without the encumbrances of bodywork. In the end, the model is essentially the drivetrain and rear axle of the car, on top of a paneled base, with a pair of lever-operated controls as well as Powered Up control for other functions.

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Features:

Suspension

Rear-Wheel Steering

Drive

9-speed, 6-clutch nonsequential transmission

Differential Lock

 

Aesthetic:

There isn't really an aesthetic, though I tried to keep the mechanical bits black, and the base is a constant LBG.

Spoiler

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The bare base

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The bottom

 

Suspension:

Perhaps I would have limited this model to a basic transmission demonstration, were it not for Koenigsegg's unusual triplex suspension design. Taking inspiration from previous Lego renderings of this design, I designed a suspension with hard shocks for each wheel, the central spring (heave spring?), and the Z-shaped anti-roll bar.

Spoiler

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Steering:

Because the real car features rear-wheel steering, I did so too. There is a basic PF Servo design with a rack, with the motor being controlled by a PF switch connected to an external wheel. This switch is hooked up to the custom camera battery stuffed inside the PU hub. There is also castor angle and kingpin inclination.

Spoiler

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Drive:

There is a hidden PF L-motor, controlled by a switch, like the steering motor, which runs the V8 piston engine and then the rear wheels, after passing through the transmission.

Spoiler

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Transmission:

The transmission is naturally the highlight of this build, and aims to replicate the real car's complicated setup. The real car has six individual clutches, and is built in a 3x3=9 setup. There is then one clutch for each of the two sets of three gears, and because all the shifting is done by simply clutching and unclutching gears, without any mechanical setup, shifts can be wildly fast, and can jump from any gear to any other gear immediately. Additionally, there is a clutch to engage reverse, as well as a clutch controlling the rear differential, for eight clutches in all. In my simplified design, each side of each transmission driving ring acts as a clutch. The basic gearbox is, like the original, composed of two sets of three-speed gearboxes, with one also having an additional reverse gear, making it a 9+3R transmission (two Rs are ignored). I also connected a driving ring to the rear differential to simulate the locking of it, but in order to simplify design, it is connected to one of the other clutches through a linkage, such that the lock is always engaged in gears 1-3. This makes partial sense, given that slip situations in a car like this are most likely in hard launches, but is also kind of stupid in that most corners are taken in lower gears. I probably should have made an individual motor control it, but I didn't think of it in time. The shifting itself was controlled using all four of my PU motors, two Ls and two XLs, each one controlling one of the driving rings for the 3-speed and 3+R transmissions. With complicated programming, I was able to create a realistic control setup. This consisted of a 3x3 square of blank dots, which corresponded to gears 1-9 in the same pattern as my calculator. Beside this were three buttons with square symbols on them, controlling Park, Reverse, and Neutral. There was also + and - buttons to allow for sequential shifting through the gears, as well as a dial to indicate which speed was in use (1-9 for the normal speeds, and 17, 19, and 15 for P R and N, since they are the 17th, 19th, and 15th letters in the alphabet, respectively).

Screenshot_20210501-122355.pngThis control allowed for shifting in both sequential and nonsequential modes. Of note is the Park setting, which engaged two gears at once on the output gearbox, locking the wheels, while leaving the input gearbox in neutral, so that the engine could continue idling, as in a real car. To really understand its operation, it is probably best to watch my video, below.

Spoiler

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Overall, this was quite an interesting model to build, and I liked the basic concept of building an interesting drivetrain without having to build a model around it. The Powered Up was also very cool to watch as it shifted very smoothly and reliably through gears, directly to any gear I selected.

My images are at: https://bricksafe.com/upload

 

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Great work! Interesting read, I like the functions you managed to implement. The mechanics are the most fun part of a build, so doing a series like this seems like a good solution. Looking forward to your next builds!

Edited by Jerry LEGO Creations

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Nice work! Been waiting for this. The Jesko is an amazing piece of mechanics, and this is a very good rendition of it. I love that everything is visible, and not hidden behind panels. This does the advanced mechanics justice!

Hope to see more like this!

_ED_

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Cool project, and I thing the total RC shifting and "driving" is very cool. That way such a complex gearbox can be seen working without having to move 3 kg of weight. 

Only building the drivetrains seems like a pretty good solution for you as your mechanisms are very good, but your bodywork is often lacking.

 

Btw, that freemake ad all over the screen is just a real pain. Please do something about it in future videos to make them less irritating and more enjoyable to watch :wink:

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22 minutes ago, Gray Gear said:

Btw, that freemake ad all over the screen is just a real pain. Please do something about it in future videos to make them less irritating and more enjoyable to watch :wink:

Yeah, it is a huge pain. I have been using a different program for my videos with a much less intrusive watermark, but I run into problems with my powered up models, because I can't film with my phone and control it at the same time. I've taken video with my old digital camera (Ram TRX) and with my mom's phone (Jeep Cherokee and this model), but then I have had trouble getting them onto my phone in the right format for editing. This time, I gave up after an hour or so of trying to get the videos onto the phone, so I just used my old annoying converter. Hopefully I can come up with something better in the future!

 

I'm glad to see interest in this concept, so I'll plan on doing some more in the future. A likely prospect is a modern reinterpretation of Sheepo's fascinating Porsche PDK transmission, with separately controlled friction clutches.

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