[WIP] JCB Fastrac Two

[JLiu15]

Here's a new project I'm working on. It is a model of the JCB Fastrac Two.

https://www.autocar.co.uk/car-news/features/christmas-road-test-worlds-fastest-tractor

A modified JCB Fastrac tractor, the JCB Fastrac Two is the fastest tractor in the world, and can reach 150mph. My model will feature drive, steering, an inline-6 fake engine, and a working steering wheel. The model uses the Control+ system and features 2 C+ L motors for drive and a large angular motor (from the 42114 set) for steering.

So far, I have done some initial modeling in Stud.io. I've modeled the drivetrain and the front axle, and the C+ hub sits between them near the bottom for easy battery access. 

Photos:

Edited July 28, 2022 by JLiu15

[1gor]

Looking forward to see your solution since it is on my to do list...(with same wheels as yours)

[Jurss]

Yes, I gave permission to 1gor to build it. 

But what I can see. Wheelbase is some 5 studs too long. It should be some 27. You have some 32, if I counted correctly. Yes, I did measurments on some photo, maybe You have some more correct blueprint.

Width seems OK.

In this scale I was planning to make nice rear axle (yes on my list is also bigger version). It is pretty iconic for that tractor. As You gave there drive motors, that axle wont be that nice. Maybe put those motors vertical, and hide in cabin rear extension. 

I'm also afraid, that there could be not space for fake engine to put in this scale. But maybe You are not going to fit in scale with wheels?

Good luck with it! I wan't to see paneling in this scale. At least bonnet should be easier to do, and closer to real one.

[JLiu15]

UPDATE 2/14/22

Made some more progress on the model. I've reworked the steering mechanism's connection to the working steering wheel, and now the entire mechanism sits lower to allow the crankshaft for the fake engine to rotate. The initial chassis design is pretty much complete, with all motors and mechanisms in place.

The fake engine does sit a little high, and as @Jurss mentioned the wheelbase is a bit too long, but there will likely be compromises due to the extra room needed to steer LEGO wheels. The mudguards on the real vehicle are very close to the front wheels. Because of LEGO wheels' pivots, there will likely be more space between the mudguards and the front wheels on my model to allow the wheels to steer, so given the compromises I feel the engine will most likely be fine where it is.

Photos:

[1gor]

I suppose that your version would be without suspension. If you want to make curvy good as it should be, I suggest you to move engine backwards for a few studs; you'll need space for making stiff front curvy part of the hood. Nice to see another tractor in development.

[Jurss]

Engine lenght is correct, also almost in right place lenghtwise (?), but it is really too high. And it looks like there is space to lower it. 

I think there should be room in this scale to fit everything.

As it is longer, then maybe that hood won't look too bad/high.

OK, it is clear, that this build won't be in scale with wheels.

[JLiu15]

16 minutes ago, Jurss said:

Engine lenght is correct, also almost in right place lenghtwise (?), but it is really too high. And it looks like there is space to lower it. 

I think there should be room in this scale to fit everything.

As it is longer, then maybe that hood won't look too bad/high.

OK, it is clear, that this build won't be in scale with wheels.

It is theoretically possible to lower the engine, but it would mean rebuilding the entire front end of the chassis from scratch. The stud below the crankshaft (which needs 3 studs to make a full rotation) carries the axle for the steering wheel, and below that is the bracing for the front axle's hubs. The steering motor is also as low as possible in this design. So lowering the engine another stud would mean a completely new front axle, with new steering mechanism and everything.

While I will definitely rebuild it if it proves impossible to model the hood and make it look good at the given engine position, I will keep it as it is as long as I can work with it. My philosophy is still that if I have to make major changes to the design for only a slight improvement in overall looks, then the change isn't worth the time and effort.

57 minutes ago, 1gor said:

I suppose that your version would be without suspension. If you want to make curvy good as it should be, I suggest you to move engine backwards for a few studs; you'll need space for making stiff front curvy part of the hood. Nice to see another tractor in development.

https://www.google.com/search?q=jcb+fastrac+two+engine&sxsrf=APq-WBuYXscYLvfmieGeahZRLtqE9FH0NQ:1644856517080&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiHvqCD0P_1AhVJMt8KHUezBF4Q_AUoAXoECAEQAw#imgrc=k8_eqgdGSosBqM

It looks like the engine is already in the correct place. Moving it further back would push it into the cabin space.

[1gor]

I have that image for a while on my mobile phone, so I know the engine position. My suggestion was based on my experience with Fastrac hood.

[JLiu15]

UPDATE 5/26/22

I finally got around to making some more progress on the model. It's still only a digital model so far, but I got the first parts of the bodywork modeled. I've modeled the lower body panels, which is primarily Technic but uses some System pieces as well. I'm pretty happy with how it turned out - the spacing between the bottom panels and the front wheels might be a bit too large to allow the front wheels to steer, but overall the proportions look alright. I've also incorporated two liftarms marking the rear of the cabin, as well as a switch to access the power button on the hub.

Photos:

[1gor]

Sides look good; I wonder if those slopes could be more suited than small panels...

 

 

[JLiu15]

UPDATE 5/27/22

Made some more progress on the bodywork. The interior, roof, and side panels around the cabin are now in place. I continued using a combination of Technic and System pieces, where larger sections are made using Technic pieces and System pieces are used to polish the look. The cabin has a driver's seat and working steering wheel inside.

@1gor I tried using System pieces as an alternative to the #21 and #22 panels. However, I wanted to keep the 3x11 Technic panel in place as it forms a very robust connection. Because of this, I wasn't able to come up with a solution that makes the System pieces fit nicely around the Technic pieces due to their height differences.

Photos:

[Jurss]

Pretty OK so far.

I need to tell, what bother me - engine needs to be at some angle, leaning down at the back. I did it in my smaller model, should be possible in this size.

[JLiu15]

10 hours ago, Jurss said:

Pretty OK so far.

I need to tell, what bother me - engine needs to be at some angle, leaning down at the back. I did it in my smaller model, should be possible in this size.

Thanks! Making the engine angled might be a bit tricky at this point without a radical redesign, since it is surrounded by structural elements. The shafts for the engine and the working steering wheel would both need to be angled.

[JLiu15]

UPDATE 6/4/22

Made some progress on the rear of the model. The yellow part behind the cab is made primarily with Technic panels, and there is a black panel for the JCB logo. The air tanks (not sure what they contain in the real vehicle) sit just behind the cab, and are attached at an angle like on the real vehicle. Lastly, I reworked the bottom of the chassis a bit at the very rear in order to mimic the diffuser (I think) on the real vehicle.

Overall, I feel that there were some parts that could be improved here. For instance, the black JCB logo panel is slightly recessed in the real JCB Fastrac Two. However, there was not much space to model anything with depth right there (I already had to rework the positioning of some beams in order to allow more space there), and any result would likely be a weird setup in LEGO, especially as I would likely have to use System pieces to make the recessed part look right. The rear diffuser is also not the most accurate - the one on the real vehicle is much thinner and angles upwards near the wheels, but building anything thinner that 1 stud would likely require System pieces such as plates, and the connections to the chassis won't be as robust.

At this point, the only things I need to do are making the hood and wheel arches. The wheel arches will probably be the hardest part of the build due to their complex curves, as well as providing enough room for the wheels to steer (as the wheel setup I'm using don't pivot at the center of the wheels, requiring more space for them to steer). The hood will be built as a separate module, as it needs to be openable to reveal the fake engine.

I created some renderings of my current progress with Stud.io:

[Jurss]

Rear is really OK.

6 hours ago, JLiu15 said:

The rear diffuser is also not the most accurate

I would tray something with panels #3 and #4 on the sides.

[1gor]

I like your approach using technic parts

[JLiu15]

10 hours ago, Jurss said:

Rear is really OK.

I would tray something with panels #3 and #4 on the sides.

I've thought of using panels #5 and #6 for this part at first. However, I'm not sure if the ground clearance will allow for it as the chassis is already quite close to the ground.

5 hours ago, 1gor said:

I like your approach using technic parts

Thanks! Overall pretty satisfied with my progress so far.

[JLiu15]

UPDATE 6/5/22

A small update - I've added dish pieces to the rims to hide the spokes, as well as windshield pillars. The rim inserts are similar to those on the 42054 CLAAS Xerion. I originally wanted to use flexible hoses for the windshield pillars, but decided to use rigid pieces instead as there's very little curvature to the real JCB Fastrac Two's windshield pillars. Additionally, positioning flexible pieces is a pain in Stud.io (I could never get it to work right), so this will also make it easier for me to make instructions for this model. I've also changed some blue pins/red axles to black, as well as changed the firing order of the fake engine to match a real straight-6 engine. While real straight-6 engines use crankshafts spaced 120 degrees apart (which is not possible with LEGO axles as they only allow for 90 degree spacing), I still prefer it over the seemingly random firing orders of mini piston engines in official LEGO sets.

Stud.io rendering:

[Philtech]

I like your model. Looks really like the real one so far. I am curious how it is going to look like when it is finished.

[JLiu15]

1 hour ago, Philtech said:

I like your model. Looks really like the real one so far. I am curious how it is going to look like when it is finished.

Thank you!

[JLiu15]

UPDATE 6/6/22

Added some more paneling to the bodywork. I added some panels above the rear wheels to form the wheel arches. This was a difficult part - there's not many LEGO pieces small and thin enough to create the distinct curve here. I ended up using the new 3L extensions for the #21 and #22 panels. They're thin and have a bit of curvature to them.

I also added the paneling around the hood. In a video, it's shown that when the hood opens, the black section below it does not open with it, so all the paneling here right now is connected to the chassis instead of the separate hood module which I will be making later. It was difficult getting the paneling here right due to the complex flowing nature of the black sections, and the panels here are all placed at angles. Speaking of the hood, I also added the attachment point for the hood behind the fake engine, as in the video the hood opens upwards and is hinged near the cab.

Photos:

Edited June 6, 2022 by JLiu15

[Jurss]

Pretty good solution for that rear fender.

[JLiu15]

10 hours ago, Jurss said:

Pretty good solution for that rear fender.

Thanks! Dealing with complex curves in LEGO are the worst, lol.

[1gor]

7 minutes ago, JLiu15 said:

Thanks! Dealing with complex curves in LEGO are the worst, lol.

This is somehow familiar...

[Milan]

58 minutes ago, JLiu15 said:

Dealing with complex curves in LEGO are the worst, lol.

But so satisfying when done right.