[TC18] N-Box

[howitzer]

I thought a while about whether to enter this contest or not, as I'm not a car enthusiast nor I have many proper car-parts to make good axle assemblies etc. But I have never really built a car of my own design, so I wanted to take this as a challenge to build something new. The next obvious problem was choosing a car I want to build. I spent a while browsing different kinds of cars and stumbled upon the Japanese concept of kei cars, which is a category of small, practical cars especially designed for crowded metropolises of Japan and from those I chose Honda N-Box as the model I'm attempting to build: https://en.wikipedia.org/wiki/Honda_N-Box

My basic problem in building cars is my lack of parts, especially for steering and exterior so I won't be able to sculpt it to perfection nor will there be driven front wheels unlike the real counterpart, which comes with front-wheel-drive and all-wheel-drive. I'll probably omit the suspension too, but I'm not there yet so we'll see.

I started with modeling the exterior in LeoCAD, with continuing to the interior once the exterior is complete enough:

[syclone]

Kei cars are very interesting vehicles, too bad there's no lower tax on such vehicles outside Japan as many of them are fantastic feats of minituarization and ergonomics. Looking forward to this model!

[brickless_kiwi]

Kei cars are great fun. Lack of parts leads to being creative with what you have trust me I have had to redesign mine three times now as I don't have the right parts.

[sirslayer]

and remember, it should fit into the trailer of Lego set 42098 !!!

[1gor]

Since it has 3 cylinder transverse engine you can make proper engine and use old 24tooth (4L) differential, but without proper suspension at the front 

Boxy design could be pretty good replicated with LEGO

[howitzer]

12 hours ago, sirslayer said:

and remember, it should fit into the trailer of Lego set 42098 !!!

The red beams in the screenshot mark the maximum dimensions of a car in this contest.

Which is a funny thing, considering that I scaled the model around the wheel I'm using and that means it's almost going to fill the available space. In reality these cars are as small as proper cars can be, while the Car Transporter is a lorry, so with my scaling, it's more like a van compared to the Car Transporter set. But at this point I don't care, as the wheels in question are the only ones I could use and even then they are on the smaller end of the contest-approved wheels.

11 hours ago, I_Igor said:

Since it has 3 cylinder transverse engine you can make proper engine and use old 24tooth (4L) differential, but without proper suspension at the front 

Boxy design could be pretty good replicated with LEGO

Thanks for the tip, but unfortunately I don't own that differential, only the oldest 28-tooth ones and the newest 28-tooth (not Torsen) one. I've yet to determine which kind of engine I'm going to build but it's going to be connected to the rear wheels. The problem is more about the steering assembly, as I don't have any parts that would enable the wheels to be both driven and steered at this scale or at least the turning pivot would be placed too far away from the wheel.

[1gor]

Perhaps you can use old one and transfer drive to 12 or 16 tooth gear? For  (a bit) closer steering point to outer sides is to use CV joints and to place wheel like on 42093 set...

[Go-Kart]

16 minutes ago, I_Igor said:

Perhaps you can use old one and transfer drive to 12 or 16 tooth gear?

This transfer works with the 16 tooth gear. I used it for my TC18 WIP (need to upload some pictures). However, my solution requires some play and flex because it does not seem to fit easily in the Lego geometry.

First post here :)

[1gor]

47 minutes ago, Go-Kart said:

This transfer works with the 16 tooth gear. I used it for my TC18 WIP (need to upload some pictures). However, my solution requires some play and flex because it does not seem to fit easily in the Lego geometry.

First post here :)

Thanks for clearifying, since I remember that this solution is used on 8865 set.

Perhaps you can post an image to help @howitzer; of course it is @howitzer's topic and topics "owner" has last word. 

[howitzer]

1 hour ago, I_Igor said:

Thanks for clearifying, since I remember that this solution is used on 8865 set.

Perhaps you can post an image to help @howitzer; of course it is @howitzer's topic and topics "owner" has last word. 

I actually have 8865 but it doesn't have driven front wheels so I'm not sure how to adapt it's parts for such a purpose and neither has 42093. Any tips on how to accomplish this without dedicated steering parts would be welcome though :)

At the moment I'm trying to throw together some assemblies to see if they can be made to work here.

Edited April 10, 2020 by howitzer
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[1gor]

1 hour ago, howitzer said:

I actually have 8865 but it doesn't have driven front wheels so I'm not sure how to adapt it's parts for such a purpose and neither has 42093. Any tips on how to accomplish this without dedicated steering parts would be welcome though :)

At the moment I'm trying to throw together some assemblies to see if they can be made to work here.

Perhaps this could help you a bit (I've build it in the meantime...but photos are not something special...)

https://bricksafe.com/pages/igor.ipsa/cars/steering_idea

[brickless_kiwi]

or how about a radial departure... go rear engine rear wheel drive like a group b rally car...

[Go-Kart]

23 hours ago, I_Igor said:

Thanks for clearifying, since I remember that this solution is used on 8865 set.

Perhaps you can post an image to help @howitzer; of course it is @howitzer's topic and topics "owner" has last word. 

Sorry, I got you wrong. I was referring to the new differential and a 20 tooth bevel or double bevel gear. I have a picture of my (probably illegal) solution in my TC18 WIP

[super-jaschka]

I do not impose, but KIA is easier to do front or not...

https://www.turbosquid.com/de/3d-models/3d-model-kia-soul-2020-1392598

[howitzer]

Hi, and thanks for all the comments. I found the solution for steering with driven axle (after a bit of searching I found that after all I do have the parts necessary). Then another problem arose in how to fit an engine under the hood. The fake engines I knew of previously were far too large so I had to think of something new to make it fit. This is what I accomplished so far:

(Ignore the steering joint, it's just a placeholder)

Now I will only have to find a way to route the engine to the differential while supporting everything properly.

[howitzer]

Ok, so it was much harder than I anticipated to make a structure that both works (drivetrain+steering) and is supported well enough to actually hold together and still be functional. I went through numerous iterations in CAD and had to start over many times but I think I finally managed to achieve what I wanted to. The front of this car is of course very cramped but along with it the main problem was the difficulty of managing half-stud offsets that resulted from the combination of my parts limitations and the required size. 1 stud more in width would have eased up things considerably. The current parts palette for making half-stud offsets is very limited so I had to get quite a creative to make it work.

Here's a couple of photos:

Edited April 18, 2020 by howitzer
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[NoEXIST]

I have to try same crazy little engine

[Mechbuilds]

I would use an half beam and have those bushings in the bottom side so the pistons wont fly out. 

[howitzer]

I had to abandon this project for now, as I found out that there's no good way to sculpt the front of the car with parts I currently have. I'm going to buy some more at some point and attempt to finish it later, but there was no time to order more parts and still be able to finish the design. CAD building didn't seem to work for me either, as it's not that easy to make sure your build is structurally sound while still allowing all the moving parts move, but the biggest problem for me was the missing mudguard parts and my inability to model the flex axles properly. So at the very least I would have to make test builds with real parts to make sure all the parts fit, but that was impossible in the timeframe of the contest. I'll continue with the bodywork at my leisure time and hopefully finish it some day.