[MOC] Toyota Hilux Truggy RC 1:8 Scale (with custom electronics)

[gyenesvi]

 

Hi Eurobrickers!

This time I'm here with my first build that explores non-lego electronics components for maximum off-road performance :) I have always been curious about what proper RC electronics could do with Lego, how far the performance could be pushed without damaging lego parts or using metal parts. So this is the first chapter in this exploration. As usual, I am more interested in off-road stuff as opposed to super fast cars, such as crawling, precision, maneuverability and good suspension.

I start on a fairly large scale for two reasons. One is to see what the electronics and the parts can handle, and second is that on this scale I can maximize the performance os suspension / drivetrain. For crawling, live axles are great, planetary hubs are a must to minimize the stress on drivetrain components, and on this scale the axle design of @Attika is superior, especially with deep rims and 95mm RC tires, so I started with adopting that to my needs and building a generic chassis around them and the electronics components. For the bodywork, I choose a truggy because they are designed for crawling and are typically minimalistic, which is good for weight saving. And when I started searching for truggies, most of what I found turned out to be a Toyota Hilux, so I just went with that. The largest wheel arches are a good match for 95mm tires, and dark blue was a color in which they are available and I already had many parts in, so it was an easy choice.

Features

• All wheel drive with about 6.5% front wheel overdrive
• Triangulated long travel 4-link live axle suspension on both axles
• Independent 4-wheel steering, servos on the axles
• Detachable body (single piece), openable doors

Custom electronics

• Buggy motors inside L motor housing for drive
• GeekServos for steering
• Injora ESC
• 3s LiPo
• RC receiver and transmitter (FlySky)
• Custom cables with PF connectors

Chassis, suspension, drivetrain

I started with the design of the axles based on that of @Attika with the planetary hubs, but I made them 4 studs wider wrt the original 17 stud design because of using the deeper rims and also for a wider stance. My main objective was to integrate the GeekServo on top of it. A key simplification factor I used is the lack of open differentials (would be locked for crawling anyway), this way reducing the space requirement of the gearing, and allowing a flatter profile and lowering the servo while fixing it in a simple and solid way. The steering linkage has really small amount of slack, and the 8T gear on the rack allows very powerful steering. In fact the GeekServo is so strong (especially in this configuration), it can steer the wheel under any circumstances on any surface I tested. On the rear axle, I managed to lower the springs for a more compact suspension to leave space for the bed above it.

The suspension is a 4-link triangulated one using 9L links that keeps the axles in place even without a panhard rod.

In the drivetrain I wanted to experiment with front wheel overdrive. First I built one with 25% overdrive using 16:16 gearing on the back and 20:16 gearing on the front. It worked, however it felt a bit too much and was not flawless; the 20:16 gearing offset the front driveshaft to the side which created an asymmetric load at the point of the driveshaft entering the front axle which generated quite some wear over time. Also, first I used 12:12 gearing inside the axle as a closed differential, which also worn out after some time.

After seeing an RC video that tested 5-6% overdrive against 25-30% overdrive, and concluded that significantly more than 5-6% is not really beneficial for climbing, I thought I'd try a more modest one. The current one on the image below uses 20:12 = 5:3 gearing in the front, and 2 stages of 20:16 gearing on the rear, resulting in 25:16 ratio. The ratio of the front/rear is then 16:15 = 1.0666, so roughly 6.5%. Most importantly, this setup is symmetric, keeping both ends of the driveshaft centered. At the same time I used a 12:20 gearing inside the axle as a differential, taking some load off. So far it has not cracked..

Here is the overall chassis. The motors look like L motors, but they have their insides replaced with that of a buggy motor, as that has the same size as the L motor's, so fits perfectly. This modification is not my own, but was done by @Jantayg and he lent me the motors for testing (the pinion gear was replaced and the thermistor was taken off and soldered back in). They are quite amazing. I measured their speed and torque against the Lego L motors, and found that they have about 1.8x speed and 1.65x torque, so almost 3x power overall!! At the same time, their speed is also in a very reasonable range, about 900 RPM on a 3s LiPo, which means good speed control but a good amount of punch at the same time, quite perfect for lego crawlers. All in a very good form factor! I only wish such a motor was available off the shelf. Luckily, the red chinese PF replicas you can find on Aliexpress approach these ones in performance; I ordered some and measured that they have about 2.5x the power of a lego L motor, only a bit worse then these modified ones. I haven't yet tested those in a build though..

Control Electronics

For control, I am using this Injora ESC. It's quite small, about 5x3x1 studs in a nice housing that can be easily attached to Lego parts with sticky tacks and has a turn-on button and status LED. It is designed for smaller scale RC crawlers, but for lego motors it is more than enough, and allows for quite precise speed control. In fact, in the video the model often moves slowly not because that is its max speed, but because I wanted to move with precision; its top speed is much faster than that. Apart from that I use a FlySky transmitter and receiver, and a 3s LiPo.

I also had to make some custom cables for connecting the motors to the ESC and splitting the output of the ESC for the two motors to avoid stacking them on the same PF port (I made several versions).

Unfortunately, currently the cables result in a bit of a mess.. It would be nice to house these electronics in a 3d printed box or something..

 

Bodywork

For the bodywork, I was aiming for something simple but rugged, but at the same time I wanted to test how the whole setup would work with some actual weight, whether I can later try to build a more detailed scale model at this large scale. I really like 95mm tires, both Lego and RC ones (I bought these inexpensive ones from Aliexpress, option TN1003), as they go really well with large 15 stud fender parts, both the Defender ones and the ones from sports cars. So as I mentioned in the intro, a Toyota Hilux truggy seemed like a good choice, and the Bugatti fenders went well with that, along with some long curved slopes for the hood available in dark blue. I wanted to replicate the characteristic front grille, which I managed by using large window pieces and a lot of small grille parts :) The rest of the body is a just a few large panels and beams, and a simple bed to accompany it with some roll-bars, all connected together to a single piece so that it can be mounted in the chassis on a few points, like in a 'real' RC car.

Here are some more renders and images of the complete model.

More images are available on Bricksafe.

I haven't made instructions for this because of the large amount of custom parts, but the Studio model is available on Rebrickable.

 

Altogether, the model has very good handling, both for speed and steering, and I am quite satisfied with the power of the motors. This all shows to me that Lego RC has much more potential, than the official electronics. And out of all these components, the only 'dangerous' one for the plastic parts are the powerful the motors, but even that danger is minimal in this setup; for smaller models it would even be less (even with this heavy model, the wheels rather spin under it than get stalled). It was really fun playing with this model and making all these video footages!

Let me know how you like it and what you think about all those possibilities with custom electronics!

Cheers,

Viktor

Edited October 27, 2024 by gyenesvi

[N1K0L4]

Awesome model, I especially like the front hood, looks very good.

I personally think the tires contribute a lot to the climbing preformance, it would be good to know if you tested it with the LEGO ones too to see the difference.

In terms of electronics, I have one idea for the future. Since you're using your own motors and speed controllers, you could find a brushless setup that fits in PF L/Buggy motor/BuWizz motor housing. That would make it even more powerfull.

[Aurorasaurus]

41 minutes ago, N1K0L4 said:

you could find a brushless setup that fits in PF L/Buggy motor/BuWizz motor housing. That would make it even more powerfull. 

I was looking for just that today, that motor size is 130. From my quick search, that size in brushless doesn't seem to exist. But I think it could be done somehow.

As for the truggy, I love it, the climbing is amazing. I'd love to see some more footage of it at top speed on gravel/sand too though.

[Lipko]

It looks lovely and very smooth! Though looks like more 1:10...1:12 to me.

[2GodBDGlory]

Very cool build!

You've been expressing interest in 3rd-party electronics for a while, but I guess I was subconsciously wondering how that rather messy category of build would contrast with your typically pristine presentation of models! You definitely did a good job in the end, though, with the usual clean digital build! What's the theory behind the front axle overdrive? That's not a strategy I've heard of before. It's cool that the buggy motors fit in the L-motor housings! I wonder if the same motors are used in clone buggy motors and those red L-motors.

The body looks nice too! It's fun that you modeled the slightly older Hilux than usual, too

[msk6003]

3 hours ago, Aurorasaurus said:

I was looking for just that today, that motor size is 130. From my quick search, that size in brushless doesn't seem to exist. But I think it could be done somehow.

As for the truggy, I love it, the climbing is amazing. I'd love to see some more footage of it at top speed on gravel/sand too though.

Kyosho Mini-Z use 130 motor and has brushless version. But Lego L/Buggy/Train/C+ large angular motor's internal motor is little bigger than 130. M/PUP M/EV3 M/C+ medium angular use 130 size but in my test, those motor use little higher voltage unlike normal 130 motor which used in Tamiya Mini4wd model.(Usally work on 3v) But it doesn't matter on this topic, so still can swappable internal motor.

 

PS. 8183/8184 also use 130 size for drive motor.

Edited October 28, 2024 by msk6003

[Igor1]

Further proof that Buwizz.chose the wrong implementation for the body of their Buggy motors. The L-motor body is ideal for more powerful solution.

MOC is beautiful!

Edited October 28, 2024 by Igor1

[gyenesvi]

Thanks for all the comments!

4 hours ago, N1K0L4 said:

I personally think the tires contribute a lot to the climbing preformance, it would be good to know if you tested it with the LEGO ones too to see the difference.

Sure they make it better, though I think these cheap RC ones are not that great either, they are not as sticky as I expected. In the 107mm range, I have some proper RC4WD tires, I'll test those next on a different chassis :) Also, I have been thinking of adding more weight to the wheels to make them more grippy. RC cars use lead on the rim, real crawlers use water inside the tires, in Lego it is possible in some cases to put another, maybe thinner tire under the outer one..

4 hours ago, N1K0L4 said:

In terms of electronics, I have one idea for the future. Since you're using your own motors and speed controllers, you could find a brushless setup that fits in PF L/Buggy motor/BuWizz motor housing. That would make it even more powerfull.

Yeah, I keep thinking about that as well, there are some nice experiments in other threads.. I think two promising directions are the A2212 type outrunner motors (either in XL housing, as you suggest, or in a custom 3d printed mount with 1-stage planetary gearing) or the 24xx type inrunner motors with a custom planetary gearbox attached. I haven't seen any that would fit into the L motor housing though.

3 hours ago, Aurorasaurus said:

I was looking for just that today, that motor size is 130. From my quick search, that size in brushless doesn't seem to exist. But I think it could be done somehow.

31 minutes ago, msk6003 said:

But Lego L/Buggy/Train/C+ large angular motor's internal motor is little bigger than 130. M/PUP M/EV3 M/C+ medium angular use 130

As far as I understand, as @msk6003 says, the M motor uses 130 size, and the L uses something like 180 size maybe.

31 minutes ago, msk6003 said:

Kyosho Mini-Z use 130 motor and has brushless version.

And yeah, that's the only one I know of that would fit there, but it's quite expensive, about $50. Maybe in a custom 3x3 housing (3d printed) it could work, and the planetary gearset of an M motor could be reused. That would be an interesting direction to try..

3 hours ago, Aurorasaurus said:

As for the truggy, I love it, the climbing is amazing. I'd love to see some more footage of it at top speed on gravel/sand too though.

Thanks, unfortunately I don't have such footage, not sure if I'll be able to make some before I dismantle it..

3 hours ago, Lipko said:

It looks lovely and very smooth! Though looks like more 1:10...1:12 to me.

Thanks, I had some trouble determining the scale, but I figured that wheel arches come from a 1:8 car, which uses 81mm tires, so this one with 95mm ones should be around that scale as well. Also, 1:8 scale translates to 76cm wheels in real life, which is kind of believable for a stock version at least.. In any case, I would not think it would be smaller than 1:9, but definitely bigger than 1:10.

1 hour ago, 2GodBDGlory said:

Very cool build!

You've been expressing interest in 3rd-party electronics for a while, but I guess I was subconsciously wondering how that rather messy category of build would contrast with your typically pristine presentation of models! You definitely did a good job in the end, though, with the usual clean digital build! What's the theory behind the front axle overdrive? That's not a strategy I've heard of before.

Thanks, yeah, the digital build helps with the presentation, and even GeekServos are available as custom parts :)

As for the front wheel overdrive, the idea is that for crawling, it is better if the car tries to pull itself up instead of pushing itself, because then it's less likely to flip itself over. Also, if it catches a ledge with the front wheels, those have more grip than the rear ones. At this point I don't know if that actually makes a difference in lego because it might not have enough weight / tire grip, but it was a simple but interesting challenge to make it. Actually, real crawler buggies go even further, the most versatile ones have separately detachable front / real wheel drive, and they can change on the go where they want to put the power. So instead of overdrive, they simply can switch off rear wheel drive.

1 hour ago, 2GodBDGlory said:

It's cool that the buggy motors fit in the L-motor housings! I wonder if the same motors are used in clone buggy motors and those red L-motors.

That's a good question, might even be so!

1 hour ago, 2GodBDGlory said:

The body looks nice too! It's fun that you modeled the slightly older Hilux than usual, too

Well I did not overthink that part, maybe because that's what truggies are like in reality and RC models.

38 minutes ago, Igor1 said:

Further proof that Buwizz.chose the wrong implementation for the body of their Buggy motors. The L-motor body is ideal for more powerful solutions.

MOC is beautiful!

Thanks! Yeah, I wish Buwizz made these kind of motors, they seem to have part of the resources for it already. I actually proposed the idea to them, but they think the buggy motor has a better form factor.. Sure, if you want direct drive to the wheels then it's good, but if you want to build a drivetrain, then they are super difficult to work with, take up a lot of extra space (and half stud offsets) and have too high RPMs for slower cars.

[Lipko]

18 minutes ago, gyenesvi said:

Thanks, I had some trouble determining the scale, but I figured that wheel arches come from a 1:8 car, which uses 81mm tires, so this one with 95mm ones should be around that scale as well. Also, 1:8 scale translates to 76cm wheels in real life, which is kind of believable for a stock version at least.. In any case, I would not think it would be smaller than 1:9, but definitely bigger than 1:10.

A real Hilux is about 190 cm wide, your model is about 17cm wide (the body) therefore the scale is about 1:11.

Yes, I am not fun at parties.

[NV Lego technic]

I think I saw this in the Buwizz camp this year, it looks really cool, especially in the Dark blue color. As much as I remember, you had some sort of problem with cracking noises, did you fix it?

[gyenesvi]

23 minutes ago, Lipko said:

A real Hilux is about 190 cm wide, your model is about 17cm wide (the body) therefore the scale is about 1:11.

Which model year? :)) For a 1980 model, which this one is modeled after, I found 161 cm body width, which would result in about 1:9.5 scale if we scale it by the width. But I suspect that scaling it to other parts would result in something different. For example the stock wheels on those ones were just 73.3cm in diameter, that would translate to 81mm stock tires on 1:8 scale.

But anyways, this is not a scale model, that's not the point. I just tried to illustrate the size of it, and it definitely feels bigger than 1:10 scale lego cars. It's something like your Dakar car in size. What scale is that? I think I could settle on 1:9. How about that? :))))

5 minutes ago, NV Lego technic said:

I think I saw this in the Buwizz camp this year, it looks really cool, especially in the Dark blue color. As much as I remember, you had some sort of problem with cracking noises, did you fix it?

Yeah, that was it with the original 12:12 gearing in the axles and asymmetric drivetrain I write about above. Since then I have redesigned it with less overdrive and 12:20 gearing in the axles, which relieves some stress from the gear mesh. Seems better now, but maybe over time it would also wear out somewhat..

[2GodBDGlory]

That's interesting about the overdrive!

1 hour ago, gyenesvi said:

Also, I have been thinking of adding more weight to the wheels to make them more grippy. RC cars use lead on the rim, real crawlers use water inside the tires, in Lego it is possible in some cases to put another, maybe thinner tire under the outer one..

In the past, I've stuffed Lego tractor tires with marbles to up the weight. It's worked pretty well for me, and I guess it could be done puristically with the ball bearings used in some Mindstorms sets, but I think water would also work fairly well!

Also, that's a beautiful picture of the real truck up there... Now I want it as a desktop background or something! Have you considered building a stock-style bed for it? It wouldn't perform as well, but it would probably look pretty nice!

[Lipko]

4 hours ago, gyenesvi said:

Which model year? :)) For a 1980 model, which this one is modeled after, I found 161 cm body width, which would result in about 1:9.5 scale if we scale it by the width. But I suspect that scaling it to other parts would result in something different. For example the stock wheels on those ones were just 73.3cm in diameter, that would translate to 81mm stock tires on 1:8 scale.

But anyways, this is not a scale model, that's not the point. I just tried to illustrate the size of it, and it definitely feels bigger than 1:10 scale lego cars. It's something like your Dakar car in size. What scale is that? I think I could settle on 1:9. How about that? :))))

The Dakar car was 1:10 scale and I think that is bigger model, whole the real car is about the same size.

[gyenesvi]

7 hours ago, 2GodBDGlory said:

In the past, I've stuffed Lego tractor tires with marbles to up the weight.

Yeah, I was thinking either that or sand.. I guess water would be hard to keep inside (and even fill).

Quote

Also, that's a beautiful picture of the real truck up there... Now I want it as a desktop background or something! Have you considered building a stock-style bed for it? It wouldn't perform as well, but it would probably look pretty nice!

Indeed, I did play with the idea of building a complete pickup variant as a more scale model when I saw some RC model of it this year at an exhibition over here. Now that @Lipko keeps me thinking about the scale, I found a pickup version that I really like and could be used for scaling. Maybe indeed it would end up closer to 1:10, because it seems to have bigger wheels.

Here is a rough sketch I cooked up quickly in Studio for the bed. I guess I'll have to get two more of those fenders..

BTW, these fenders are really not great for these kind of cars, they just curve in the wrong place / direction, the bottom should go inwards, instead of coming outwards.. I wish there would be different fenders as well..

Edited October 28, 2024 by gyenesvi

[Krxlion]

There you go Viktor! You have reached the dark side of non-lego electronic, and now we have an evidence of it, haha. How do you like it? Are you gonna build from time to time your future models with this RC gear? I really like that you have put overdrive on front, it shows that you studied RC off-road cars, or off-road cars in general, great work! Regarding the chinese L-motors I heard they have good RPM, but very poor torque, like they took one stage from two-stage planetary setup in their housing, but I might be wrong, and you can correct me on that one. As always you made sure you pack your model in a nice body, which I really love. Don't worry about messy cables, I think that in future you will find solution to that as well. :)

Really looking forward to your next build, I always know it will be something good when you publish your MOC here, great work once again!

PS I forgot to mention that your 4-link setup looks great, the model has so much ground clearance thanks to it!

[gyenesvi]

3 hours ago, Krxlion said:

There you go Viktor! You have reached the dark side of non-lego electronic, and now we have an evidence of it, haha. How do you like it? Are you gonna build from time to time your future models with this RC gear? I really like that you have put overdrive on front, it shows that you studied RC off-road cars, or off-road cars in general, great work! Regarding the chinese L-motors I heard they have good RPM, but very poor torque, like they took one stage from two-stage planetary setup in their housing, but I might be wrong, and you can correct me on that one. As always you made sure you pack your model in a nice body, which I really love. Don't worry about messy cables, I think that in future you will find solution to that as well. :)

Really looking forward to your next build, I always know it will be something good when you publish your MOC here, great work once again!

Thanks a lot! Of course I will make more models with this gear, I have several sketches on different scales. Also, with this chassis I'm thinking of different bodies. And I bought another set of batteries, ESC, receiver.. I'm especially curious about smaller models with a single (red) XL motor and a GeekServo and small battery.

About the motors, you are right that there are some chinese variants that have high RPM but low torque, I think those ones are black / dark orange-ish color, called furious L motors, or something like that. But these red ones seem better, I have measured them to make sure :)

3 hours ago, Krxlion said:

PS I forgot to mention that your 4-link setup looks great, the model has so much ground clearance thanks to it!

Thanks, glad you appreciate it!

[Zerobricks]

Well done. May I ask what's the advantage of having the front axle geared up compared to the rear?

Regarding the question of L motor housings, that was the original idea, but the motors are too enclosed for proper cooling and can't be stacked easily.

[rm8]

Toyota. Love it all

[orangetrialtruck]

Wow, amazing rock crawler!! :))

On 10/27/2024 at 10:56 PM, gyenesvi said:

Unfortunately, currently the cables result in a bit of a mess.. It would be nice to house these electronics in a 3d printed box or something..

To reduce the amount of cables in my models, I decided to solder PF connectors directly to the ESC. So I don't need to use extra XT60/90 - PF cables - this really improved the cable management. 

[gyenesvi]

8 hours ago, Zerobricks said:

Well done. May I ask what's the advantage of having the front axle geared up compared to the rear?

Thanks! About the front wheel overdrive, often used in RC crawlers, the idea is that for crawling, it is better if the car tries to pull itself up instead of pushing itself, because then it's less likely to flip itself over. Also, if it catches a ledge with the front wheels, those have more grip than the rear ones, especially if the car is at a pretty steep angle. At this point I don't know if that actually makes a difference in lego because it might not have enough weight / tire grip, but it was a simple but interesting challenge to make it.

8 hours ago, Zerobricks said:

Regarding the question of L motor housings, that was the original idea, but the motors are too enclosed for proper cooling and can't be stacked easily.

I think the stacking would not be a real problem, because the L motors can be geared together really easily due to their possible distance, in a way it is even an advantage that the gearing can be adjusted. Actually, I find that stacking the buggy motor format to the same axle is more problematic, because it wastes a lot of space and results in half stud gaps.

As for cooling, I wonder if that's actually required that much. I haven't had any problems with overheating so far, I mean I never felt the motors would heat up, and maybe the more down-gearing due to the planetary gears help with that, as the motor has more torque with less struggle? I don't know the physics of that. But this is with a totally enclosed motor housing, and some cooling gaps could definitely be added as on the buggy motor, no? Or would that make it structurally weaker?

8 hours ago, rm8 said:

Toyota. Love it all

Thanks, thought you'd like it for that reason :)

7 hours ago, orangetrialtruck said:

Wow, amazing rock crawler!! :))

To reduce the amount of cables in my models, I decided to solder PF connectors directly to the ESC. So I don't need to use extra XT60/90 - PF cables - this really improved the cable management. 

Thank you! Indeed, I realized that even XT30 connectors take up a lot of space because they don't allow the cables to bend in their immediate neighborhood. And actually the first connector on my cables picture above does exactly that, one end plugs directly to the ESC and the other is the PF port. But I did the other ones to be able to split the cable to two PF ports. Did you have a solution for that, like soldering two PF connectors onto the same output? Or did you just stack multiple motors on one PF port? I'm not sure if it could handle that, I've heard some people melting the plug with 2 buggy motors..

[ILoveSeatron]

Nice truck! I like it,especially the four wheel drive and suspension.

[orangetrialtruck]

18 hours ago, gyenesvi said:

Or did you just stack multiple motors on one PF port? I'm not sure if it could handle that, I've heard some people melting the plug with 2 buggy motors..

Yes, I've also heard about melting PF connectors (especially non-original) with two buggy motors. But decided to experiment and connect two motors to one PF port - so far so good :) But this might also be an indication that I don't play hard enough :)