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[TC20] 8830 Rally 6-Wheeler / Moon Buggy

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As many people started rebuilding their childhood favorites and first sets, I also felt like joining in, especially as I had previously thought of rebuilding my ever first technic set, albeit on a much larger scale. Nevertheless, after a quick inventory check, I realized I just have enough free parts in the right color to build 8830 with a bit of up-scaling (somewhere between 1.5x and 2x). Interestingly, the set has two names in many places (Bricklink for example): Rally Car and Moon Buggy. Actually I prefer the moon buggy, so I go with that, especially because I have 6 wheels from the Mindstorms set that look like moon buggy wheels to me :) The Rally car interpretation would require something like Jeep wheels, which I don't have, but if I win that, I'll try a wheel swap :D

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As the set does not have any functions besides steering, it would be pretty boring to replicate it as is, so I am adding some obvious functions to make it more interesting.

- pendular suspension on the first and last axle, with a bogie setup that averages the middle axle (and hence the body) between the extremes

- keep HoG steering + make the steering wheel at the front functional

- a small fake engine driven by the middle axle with differential

- maybe an upwards opening version of the front frame as if it was a cabin door

Here is my current progress, the pendular suspension, the HoG steering and the drive from the middle axle is already functional:

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Strange selection of wheels,they don't represent original model.

Just thinking out loud.

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I actually find the approach and the wheel selection perfectly in line with the competition's essence. Will follow with great interest. :classic:

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On 5/29/2021 at 6:55 AM, Jurss said:

Strange selection of wheels, they don't represent original model.

These were the ones at a roughly appropriate scale that I found 6 of (I only have modern sets with large wheels). But I also think they could be good if the interpretation of the model is a moon buggy. I agree though that it's not the best if I want to represent the original faithfully.

On 5/29/2021 at 8:45 AM, agrof said:

I actually find the approach and the wheel selection perfectly in line with the competition's essence. Will follow with great interest. :classic:

Thanks for the support, although I am a bit torn about the interpretation of the competition's essence :) On one hand staying as close to the original would encourage mainly replacement of studful beams to studless ones and staying with the original wheels, on the other hand rebuilding it with modern techniques would encourage a larger departure.. But I think a bit larger departure while keeping the overall looks sounds a bit more interesting and challenging. I'll see how it goes.

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Here's a progress update. I have been working on the remaining technical details (inline 3 cylinder engine in the middle, working steering wheel in the front, improved steering rack and suspension linkage), as well as the bodywork. As you can see, I also found some other wheels of which I have 6, that may be more appropriate.

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With the bodywork, I aimed to keep the core lines and replicate the slopes and tail with modern panels.

One thing I have never understood / liked about the original model is the rollover bars in the front; they have always looked kind of useless to me, as they are too low for the seat. I guess they have more of a cosmetic purpose. So I decided I give it a more moon-buggy like look with a more rounded frame in the front. Still not perfectly satisfied though..

Let me know what you think. Though, as I only have a day left before leaving for holidays, I won't be able to iterate too much more before making my submission..

 

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Okay, found a smoother and cleaner way of doing the front part..

Also, tested again with both wheel options. As much as I like the more modern Mindstorms wheels, I'd still say that the yellow ones are a better fit for this contest..

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I like the new front - and I agree the yellow wheels work better for this.

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I don't like those mindstorm wheels on this vehicle, but those wheels you have are not that common anymore, and yet it looks good with them.

The model is significantly bigger and this small fake mini piston engine feels out of place. You could fit something like full inline 6 cylinder with lego cylinders at the back instead.

Also the steering knob is moved off centre to the front - does it work/feel good at that location?

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5 hours ago, SaperPL said:

those wheels you have are not that common anymore, and yet it looks good with them.

Yeah, only found these old ones, but I think both the tread and the rims look cool on it.

5 hours ago, SaperPL said:

The model is significantly bigger and this small fake mini piston engine feels out of place. You could fit something like full inline 6 cylinder with lego cylinders at the back instead.

I did think about a bigger engine, but did not do it for two reasons. One is technical, as the lower part of the chassis is very dense, the drivetrain can only come up in the middle, so if I wanted to fit in something longer, more towards the back, it would just cut the main shaft in half (see grey gear in the middle below). Second, is that a moon buggy probably would not even have a combustion engine, would probably have electric motors :) So I did not want to give it too much focus, furthermore I wanted to keep the back as a cargo area (added some rock samples as well).

5 hours ago, SaperPL said:

Also the steering knob is moved off centre to the front - does it work/feel good at that location?

Again, primarily for reasons of density in the chassis, but it does actually feel quite good. In fact, steering is so smooth with a very small radius that I can't stop driving around with it :)

I have done some color optimizations and added some extra details, here are some cleaner images.

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I think this captures the feel of the original quite well.  

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I think you could fit the 6 inline if you moved the drive takeout from the differential, the 12 tooth gear, to the front side and used the blue 20 tooth gear with pin hole to go around the steering axle. This way you've got the input to the engine from the front. But yeah, as a moon rover/buggy, maybe it makes sense to have that storage space, but as a race 6-wheeler, I dunno. That's your decision here. I just think it's doable.

Also I just noticed the suspension - interesting approach in how you connected the axles with those links. Pretty neat idea.

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On 7/18/2021 at 1:51 AM, Hrafn said:

I think this captures the feel of the original quite well.  

Thanks :)

14 hours ago, SaperPL said:

I think you could fit the 6 inline if you moved the drive takeout from the differential, the 12 tooth gear, to the front side and used the blue 20 tooth gear with pin hole to go around the steering axle. This way you've got the input to the engine from the front. But yeah, as a moon rover/buggy, maybe it makes sense to have that storage space, but as a race 6-wheeler, I dunno. That's your decision here. I just think it's doable.

I understand what you mean, but as it is currently, the drive cannot go on the front, because that's where the HoG steering is routed and connected both to the front and the rear, so there it's not enough just to go around the steering axle with a blue gear. In the back, that's exactly what is happening (with a red gear going over the steering axle). I'll try to post clean renders of the drive and steering shafts to allow you to see what's happening.

14 hours ago, SaperPL said:

Also I just noticed the suspension - interesting approach in how you connected the axles with those links. Pretty neat idea.

Thanks, actually that suspension is the core of the whole build, I wanted to experiment with it, that's why I started building this model. That's why it's pretty dense, the steering the drive train and suspension crossing each other in a small space..

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