[TC25] 41999 4x4 Crawler Exclusive Edition

[gyenesvi]

Hi guys,

I suspect that the best set choices for the shrinking contest are large and mechanically rich sets, but I just had to stay true to myself and build an off-roader :) Especially that I don't yet see any such entries. So first I thought about the ground-breaking 9398 set, which I never owned because it came out in my dark ages, but then I realized that its redesigned version, 41999 is even cooler. Plus the recent Ford GT that I bought seems to be a good parts pack for the body in the right color.

Now as ground-breaking as these sets were in their time (for introducing PF motors and utilising relatively new ball joints and portal hubs), I find their (shared) mechanical side horrible; awful suspension and steering geometry, huge axles with unrealistic drivetrain, resulting in an awkwardly high stance and bouncing of the whole body as it rides. That should not be too hard to reproduce :))) So I'm going to aim for that at about 70% scale, using 68mm balloon tires (that I'll have to buy for this) on 43mm rims!

 

Planned features

- live axle suspension on 6.5L springs, keeping portal axles (okay, I'll probably get rid of the negative caster)

- all wheel drive, adding a mini fake engine for this to make sense

- all wheel steering with HoG, linkage based

- working winch

- openable doors and hood

- (I have been thinking that maybe doing a swappable body would be nice, to that of 9398, will see if it's possible / if I have parts for that)

 

Here's a sketch of the chassis and the axles I made. Besides of course the compact portal axles, one tricky point is to make the steering and drivetrains intersect each other in the right point to make it feasible. Another one will be to build a tiny enough fake engine to fit under the hood.

And here's some actual progress I made with the axles to test if the portal setup is strong enough to hold up. It seems to be okay (so far tested with non-ballon 68mm tires).

 

Edited August 3, 2023 by gyenesvi
Fixing image links

[Seasider]

So glad someone’s doing this as it’s such a great model

[gyenesvi]

On 7/4/2023 at 11:13 AM, Seasider said:

So glad someone’s doing this as it’s such a great model

Glad you like the choice, well I never saw it in real life, so this will be my first time :)

Here's some progress, I worked on the body last night and got it more or less done for the general shapes and main connection points. Indeed, the paneling from the Ford GT is perfect for this scale.

The original model does not have an opening bonnet, instead a big part of the body can be tilted, I guess in order to have access to the electronics that is deeper in the chassis. For a manual version that does not make much sense (and would be hard to do at this scale at the cost of weakening the structure and obscuring the looks I guess), so I went for an opening bonnet instead to be able to access the fake engine.

Here it is mounted onto the chassis. I think the stance is a bit too high though, so I'll try to lower it (raise the axles) at least by half a stud.

The front is still missing the which mount, and of course the internals need to be done as well.

 

Edited August 3, 2023 by gyenesvi
Fixing image links

[Thirdwigg]

You definitely understand the assignment. This looks perfect.

[SaperPL]

Why no white stripe on the front and red parts on the suspension (in studio design) ?

[gyenesvi]

On 7/5/2023 at 3:46 PM, Thirdwigg said:

You definitely understand the assignment. This looks perfect.

Thanks, glad to hear you like it :)

On 7/5/2023 at 5:10 PM, SaperPL said:

Why no white stripe on the front and red parts on the suspension (in studio design) ?

At first I tried to build the nose as in the original, one vertical layer of blue and one white beams. That looked too much, so I removed the white one to get the scale right. But you are right that I should keep the white one instead. As for the springs, the original has yellow springs, which are not available in soft version (but the red is). But maybe I'll put in the yellow harder ones just for keeping with the original.

As progress tonight, I have made an overhaul of the chassis to raise the axles by half a stud to get it more into scale. As a side effect, I also cleaned it up and strengthened it structurally. The original has many chassis parts in red, so to keep it closer I also recolored some parts there. Furthermore, the drivetrain joints had to be replaced due to the raising and changing of the angle (shortening of the axle), swapping out the U-joints to the new long sliding CV joints to account for the non-full-stud axle length required in this configuration.

Here it is with the full body in its current state:

I think the height is better this way, and with the red parts, it does look closer to the original.

Edited August 3, 2023 by gyenesvi
Fixing image links

[2ndgen]

I love this. It looks great, and by lowering it it definitely looks alot better. 

[mpj]

You must look closer to see that it is not the original one. Well done!

[Jundis]

That looks fantastic! This really is hard to tell appart from the original, great work!

[Alex Ilea]

This will win, no doubts.

[Seasider]

Those latest mods to change the colours and a bit of the dimensions are spot on. Can’t wait to see this in real bricks. Might have to dig my 41999 out and then build this if you’ll provide the digital file once this competition is over

[SaperPL]

13 hours ago, gyenesvi said:

 At first I tried to build the nose as in the original, one vertical layer of blue and one white beams. That looked too much, so I removed the white one to get the scale right. But you are right that I should keep the white one instead. As for the springs, the original has yellow springs, which are not available in soft version (but the red is). But maybe I'll put in the yellow harder ones just for keeping with the original.

Now I can see why the white was a bit too much. To make it perfectly, you'd have to make that section with half stud wide liftarms probably. Also the yellow shock absorbers weren't in my mind at that point, but the fact that there's a lot of red in the original model's suspension.

3 hours ago, Alex Ilea said:

This will win, no doubts.

That depends on what will jury vote for... and also there still a lot of time. This is a good pick, but I'm not sure how it compares to some other builds that seem more challenging.

[1gor]

It really looks spot on. 

[gyenesvi]

On 7/6/2023 at 5:20 AM, 2ndgen said:

I love this. It looks great, and by lowering it it definitely looks alot better. 

On 7/6/2023 at 7:08 AM, mpj said:

You must look closer to see that it is not the original one. Well done!

On 7/6/2023 at 8:26 AM, Jundis said:

That looks fantastic! This really is hard to tell appart from the original, great work!

On 7/6/2023 at 8:45 AM, Alex Ilea said:

This will win, no doubts.

On 7/6/2023 at 11:58 AM, Seasider said:

Those latest mods to change the colours and a bit of the dimensions are spot on. Can’t wait to see this in real bricks. Might have to dig my 41999 out and then build this if you’ll provide the digital file once this competition is over

On 7/6/2023 at 9:33 PM, 1gor said:

It really looks spot on. 

Thanks for all the positive feedback, glad you all like it! I'll surely provide the digital, probably even free instructions. I am already also thinking of motorizing it after the contest, since it turns out to be my favorite scale :)

On 7/6/2023 at 11:59 AM, SaperPL said:

Now I can see why the white was a bit too much. To make it perfectly, you'd have to make that section with half stud wide liftarms probably.

I did also think about that, will give it a try, but it will definitely be harder to  make it hold together. Now it relies on the 4x2 beam (and the black tubular frame), which I cannot build out of half liftarms. But maybe first some hypothetical renders to see if it would actually look better. Though I think it's already better than I initially thought.

[GerritvdG]

58 minutes ago, gyenesvi said:

I'll surely provide the digital, probably even free instructions. I am already also thinking of motorizing it after the contest, since it turns out to be my favorite scale :)

Really interested in building this fantastic model! Good job!

[1gor]

Motorizing it? One L motor for drive and servo for steering? I'm affraid that you should streagthen axles...

Edited July 10, 2023 by 1gor
Typing error

[gyenesvi]

12 hours ago, 1gor said:

Motorizing it? One L motor for drive and seevi for steering? I'm affraid that you should streagthen axles...

Yeah something like that, and indeed the axles probably need strengthening in that case (or just dropping the portal setup). But let's not run forward too much. First the manual one :)

[rhplus]

love your version so much, all proportions are spot on! 

anyway I had the same idea as you to shrink this set so I hope you will be OK with that. 

[gyenesvi]

On 7/10/2023 at 8:24 PM, rhplus said:

love your version so much, all proportions are spot on! 

anyway I had the same idea as you to shrink this set so I hope you will be OK with that. 

Glad you like it, and of course I am okay with someone else shrinking the same model, as long as it's not a copy of mine :) I can see your chassis is quite different, though I wonder how different you can make the body at the same scale.. Do you already have plans?

[rhplus]

48 minutes ago, gyenesvi said:

Do you already have plans?

Glad to read your words.

Well, I have not much plans yet... maybe I will try brick built front but not sure with the rest of the body (openable doors, trunk etc.)

This week I want to "finish" the chassis with winch and engine and next week start to experiment with the body

[gyenesvi]

Some progress in between two holidays.. :)

I have added the fake engine. It has to be a really flat one to fit under the hood, as there's not much vertical space, only about 1.5 studs. I made a V6 engine that relies on the 112 degree connectors and half pins. Those connectors just fit into the 7x5 frame, the piston rows cannot tilt sideways, but is loose enough to let the main shaft spin without friction. Due to the use of the half pins as pistons the whole engine is not super smooth, but good enough, doesn't jam, I have built it in real life to test it.

Here it is inside the chassis; it just fits in between the shock mounts (tested that as well, tight fit, but okay).

 

The other thing I did is the bull bar and the winch. I wanted to make the mounting of the bull bar similarly triangulated as in the original, which uses angled liftarms in a smart way. On a smaller scale, angled connectors can be used similarly.

The winch is functional with a ratchet mechanism and release lever (also built it in real life).

Also, I have realized that parts that hold the top are not DBG (as I thought based on the official instructions) but black in the original, so I have recolored them to black.

On 7/6/2023 at 11:59 AM, SaperPL said:

To make it perfectly, you'd have to make that section with half stud wide liftarms probably.

I have also given this a try, but not so many thin liftarms are available in dark blue (the key 4L is missing for example), so I could not even build a structurally weak version of it. Also, the thin stripe would be different from the rest of the stripes (especially the cross stripe on the tail), so I think it would not end up any better than now, so I won't pursue this any more.

Edited August 3, 2023 by gyenesvi
Fixing image links

[Saruzeufel]

Almost the same engine solution I came up with for my model. When I tested it with the 120° connectors the pistons barely moved (rather got stuck after 2 strokes) so I went back to 90° and even those are unreliable at best.
Looks good so far, very recognisable!

[gyenesvi]

6 hours ago, Saruzeufel said:

Almost the same engine solution I came up with for my model. When I tested it with the 120° connectors the pistons barely moved (rather got stuck after 2 strokes) so I went back to 90° and even those are unreliable at best.

Did you add round 1x1 tiles on top of the half pins? Those give them more weight and help them get stuck less often. But it's not a critical thing, so no big deal even if it skips a few strokes.. Glad you like it btw.

[Saruzeufel]

29 minutes ago, gyenesvi said:

Did you add round 1x1 tiles on top of the half pins?

I did, the ones with a pin connection on top even but even that extra weight does not do much sadly. Maybe my pins are not worn in enough to be smooth and slide properly, who knows

[gyenesvi]

After ordering missing parts (like tires) I finally started building the whole model in real life, got done with the chassis. It required adding some Panhard rods to fix the axles' sideways movement, and then I started pushing it around a bit as a test just be completely surprised that if I try to steer, the axles bind completely and the model won't move. Just to make sure, I disengaged the whole drivetrain, just left in the connection between the left and right wheels in both axles, and it still binds. So I am guessing this is because

- the axles don't have differentials, and

- it has a big scrub radius due to the portals, and

- it has all wheel steering and a resulting small turning radius

All these factors together build up so much difference between the left and right wheels' rotation rate that they simply cannot rotate together (and the tires also have enough grip so that they don't slip).

I guess I'll have to redesign the axles to add differentials, which is a problem because leaving them out was what made the portal setup possible in the first place (otherwise the axles would get too wide). So I either let the portal setup go (which is a key feature of the original) or make the axles wider.. :(

I also thought about splitting the drive axles in half and only drive one wheel, but that feels like cheating..

Edited August 2, 2023 by gyenesvi