Toyota Land Cruiser 79

[2GodBDGlory]

I think this is my fourth model of a Toyota Land Cruiser 70 now, so yeah, I like these trucks. I've now done the 2-door SWB SUV, the 2-door LWB Troop Carrier SUV, the 4-door pickup, and the 2-door pickup, so I guess the only major body style I haven't done is the 4-door SUV. Maybe someday!

Anyways, this model was made to try to make a model that would both look good and perform well, and I think I was fairly successful in that! I think I talked about the wheels I'm using in a different thread, but they're ones I custom-modeled and 3D-printed to match the LC70 style. They are stretched in diameter a bit beyond the standard Lego Racing Small rims so that they can clear planetary hubs, but they still work fine with these 81mm balloon tires, and, I think, look really cool!

Aesthetics:

Spoiler

Functions:

• Folding bed sides
• Drive
• Steering
• Suspension

Folding bed sides

The three sides of the bed all fold down, as it appears some Australian-spec beds do, but I don't seem to have taken any pictures of it. I think it might be in the video, though.

Drive

Drive was done via two clone buggy motors, powered by a custom 3D-printed case for a 3S lithium battery, outputting nominal voltage of 11.1, just like a Buwizz, and a 2.4 GHz controller. Output came from the fast outputs, was sped up by a 20:12 ratio, and sent to the axles, where it met 20:28 reduction, followed by planetary hubs. The rear differential was permanently locked, while the front was left open. I think this gear ratio provided a respectable top speed, but also enough torque (even at lower motor speeds) to do about as much crawling as the ground clearance and approach/departure/breakover angles would allow.

Steering

Steering was done with a PF Servo motor, controlled by a MouldKing 6.0 battery for proportional control. Strangely, I actually ran the steering with an 8T gear attached to the Servo's rear output, which ended up right underneath the motor, which is certainly technically illegally close to the motor, but which actually worked quite well, and was quite compact. The use of only an 8T pinion really limited steering lock, though, which was a bit of a problem. Other than the low lock, the system worked quite reliably and well.

Suspension

This was the function that took the most trial and error to get working. Both the front and the rear had triangulated 4-link systems with a significant amount of travel. The rear was simply sprung with some orthodontic elastics that had to stretch upwards when the axle went up, while the front pushed 6L links upwards, where they had to rotate a lever that would stretch large rubber bands. These link and rubber-band based systems allowed for smooth, low-friction operation and good articulation, but in the end I had far too much articulation, so the truck would often find itself rolling over even when just taking routine corners at high speed. To remedy this, I installed a basic anti-roll-bar in the rear, which had a very dramatic effect on handling, really preventing that level of body roll! I was quite pleased with that, since anti-roll bars seem to typically be included in Technic MOCs as a novelty, but this proved that they can have huge effects on certain models!

Performance

I think the truck was fast enough to be fun, and had very responsive suspension, making rough terrain a lot of fun. The biggest issues were the fragile body and its tendency for its front driveshaft to fall apart. Probably in the future I should stick to simpler ball-joint based suspensions, even though ones like this are fun to design!

Complex Variant:

This model was actually originally designed with a completely different chassis, incorporating some more complex features. Unfortunately, they slowed the truck down dramatically, so I completely redesigned the chassis. Originally, it was driven via two PF L-motors, through a remotely controlled two-speed transmission, into an inboard rear differential, which had @JoKo's clever auto-locking differential design. I mounted the differential inboard to avoid having to push the bed too far above the rear axle, but this inboard placement added a lot of complexity, making the truck pretty lame to drive. I still love the basic diff lock concept, but I don't think this was the right model to try it in. I've got a basic video of that early version here:

Spoiler

 

Summary

I'm quite pleased with this model. A bit more reliability would be nice, but performance was fun, and I at least really liked the way it looked!

 

[Paul B Technic]

This is excellent, I see a lot of these around here on the road and you have captured the design of this well.

[Daniel-99]

Oh man... I am speechless! Thank you for a nice presentation and a great truck to look at! I found your post in the morning and it basically made my day! A few days ago there was a conversation on EB why Western Europe technic guys prefer SUVs to Supercars. I found a reasonable argument that time, but now I understand, how madly I am in love with SUVs! I was scrolling the EB forum for the couple weeks, skipping most of Supercar topics. Indeed they a very technical and has breathtaking look, but my heart does not stick to them. I am a performance-over-the-look guy, and you truck have healed my heart!

Another fun fact is that I build my own SUV lately and currently I am working on the presentation. It has the similar scale to yours as well as the same philosophy behind the build. I wish we could drive our SUVs side by side one day!...

 

Now I want to speak about technical stuff.

Bodywork. Well done, the car is recognisable! Also I love the bed-design. I do understand what it takes to squeeze a rear axle under a flat bed without limiting its articulation. As I understand, your truck has no openable doors, and I am totally ok with it as long as It decreases the weight and add the rigidity to the chassis.

Drive and steering. I appreciate the efforts you put into V2 of a chassis. The SIMPLICITY ARGUMENT really works here! 2 Buggy motors works greatly here. Your words "I think the truck was fast enough to be fun, and had very responsive suspension, making rough terrain a lot of fun." was proved in the video! Not many people are honest in their presentations! An outdoor RC car should have enough speed (at least 5 km/h) to be "fun to play with", and your truck is even faster! Speaking of the steering... I am not pleased with it, to be honest. Are you planning to use GeekServo in the future (cause you already have RC controller on-board)? I will improve the steering of your truck a lot! At the same time you will not need a MK 6.0 which add its weight. Finally you will fully enjoy a responsive RC transmitter both with Drive and Steering.

Suspension. 4-link suspension is totally avoided in Lego sets, and I am so bored with both standard independent suspension and Live-axles using ball-connector as in 9398 set! Without the doubt, your truck has a great articulation, though it is too soft in my opinion. I am not a fun of rubber bands and prefer shocks! Due to my researches, the best way to make a responsive suspension with shocks is my mounting them as close to wheels as possible. There is a whole big deal to set the shocks correctly, keeping both articulation and stability on high speeds. As you have shown, anti-rowbar helps a lot, I used a carbon fibre anti-rowbar in my Buggy HORNET to achive high-speed cornering. I wonder why you put an anti-rowbar at the rear axle, but not to the front? It is well-known that front outer wheel has the most load in the fast corners, so there is a deep reason for placing ant-rowbar at the front. 

Finally, I am worrying about the front axle. It looks very compact and realistic, but it does not look strong enough to survive any bump on a high speed. I would use a classic solution with 5x7 frame. Also the front axle has negative caster angle, which is causes problems to the high speed stability.

Transmission. As I said, I love the simplicity of V2 transmission! The whole setup with planetary hubs, reinforced differentials works greatly! It is great to see how planetary hubs fit into rims! This should decrease the turning radius of a wheel a lot! The weakest part of your truck are the drive shafts! Legois U-joints are strond enough for this truck, since it has planetary hubs, but the geometry of a front shaft is wrong. It needs to be 3 studs longer (9 studs instead of 6) to mach the length of suspension arms. Otherwise you should use make  a length-varying shaft. Moreover, it is bent too much on my opinion, this increases the stress on it, and reduces efficiency. Especially, if you would put a front axle at a positive caster angle, you will need to redesign the front driveshaft. 

I saw in the video that the front driveshaft fell apart couple of times. I guess, it is caused by its wrong geometry. If the car meet a serious bump with the front wheels, the front drive-shaft faces the destruction wave because it is not well-secured by the lower links of the front suspension. To make a proper protection you should follow three steps:

• make the driveshaft parallel to the lower links of the suspension
• make sure, that the front axle does not wobble from front to back with the driveshaft removed (this will convince us that the drive-shaft does not carry any load from the front axle)
• reinforce the lower links by using brick build one.

The summary. I really appreciate the efforts you put in this car. It is an eye-catching piece of technicality! The whole chassis is very fresh comparing to the standard Lego solutions, but it has several problems, which require fixing. Hope to see more progress on this car soon! 

P.S. Some photos of the chassis will be appreciated!

 

 

[gyenesvi]

Great to see this build pop up now, I am just about to post my RC Toyota very soon :) Nice build, I like the drivetrain and suspension, especially the anti-roll bar, that is something I'd like to test in the future. However, I am not completely familiar with how it is supposed to work, I mean I get that it limits the articulation, but isn't that counter-productive? We want enough flex, no? In my builds, the flex usually is limited by the springs anyway. Maybe the anti-roll bar is less useful in that case?

The two buggy motor drivetrain is also nice and simple, I'd like to try that once in the future, but I guess I'd be okay with the speed from the slow output. With old diffs and planetaries, that seems to be plenty for me based on a previous build, at least using Buwizz motors and a Buwizz 3. Maybe these clone ones are weaker somewhat?

[2GodBDGlory]

Thanks for the nice comments, everyone!

I really appreciated your thorough response, @Daniel-99, so I'll try to answer your questions:

Yeah, I decided not to go for opening doors, largely because of rigidity, especially given the half-stud indented portion of the sides, and also because the interior was filled with functional elements, so it wouldn't look good with doors open anyways!

As far as the steering goes, I did think about using GeekServo with this RC setup for a while, but I'm now convinced that it can't work for me. The trouble is that my RC setup isn't actually a hobby RC-style one, but rather cheap replacement parts I ordered that matched this ~$100 RC car my brother had. It offers good control for the drive setup, and I have the original steering motor from the setup which can be used as well, but the trouble with GeekServo is that this board has non-standard servo control. Instead of a normal 3-pin setup, it has 5 pins, two of which are wired to a basic non-servo motor used for steering, and the other three of which are wired to a potentiometer that sends position signals back to the board, telling it when the desired position has been reached. I actually made a 3D-printed housing for this potentiometer and custom wiring that would allow me to use any PF motor for steering, so long as the sensor was attached to the steering shaft, but the printed part that interfaced with the potentiometer had to have an extremely thin part, and always broke, so it wasn't reliable. Additionally, the steering parts of the control board don't seem able to survive the 3S setup without dying, so when I was using that, I actually had a second identical control board on models with a secondary 2S power supply to run it, and a second remote to carry. So, I guess the short version is that I see no way to use GeekServo with setup, because of completely different steering logic. It could be fun to get actual hobby-grade control hardware, but it looks pretty expensive, and this works pretty good. The MouldKing box is actually surprisingly light for its size!

You're definitely right that problems are caused by having driveshafts of shorter length than the suspension links, but I'm not sure how I could practically solve it here. The front driveshaft is already as long as I can get it, because I was getting excessive wear when I tried having a HD CV joint on the top of the driveshaft. I suppose I could go to 6L suspension links, but then that's going to create more longitudinal motion of the axle throughout the suspension motion. As far as these three suggestions go:

6 hours ago, Daniel-99 said:

• make the driveshaft parallel to the lower links of the suspension
• make sure, that the front axle does not wobble from front to back with the driveshaft removed (this will convince us that the drive-shaft does not carry any load from the front axle)
•  reinforce the lower links by using brick build one.

I think the driveshaft is nice and parallel, at least without compression, and there seems to be minimal wobble. Why would you suggest brick-built links? My feeling would be that these would be strong enough in compression and tension, and wouldn't deal with other forces much, but I could be wrong about that.

Unfortunately, I think the only satisfactory way to solve my suspension issues without creating different ones (though the new issues might not be as bad) would be to increase my wheelbase, which isn't really possible in a scale model like this.

You asked why the anti-roll bar is on the back, and I guess that's because of an impression I had that that was more normal in real cars, though I guess that was wrong! Additionally, it was a bit of an afterthought, and I think I thought it would be easier back there. Looking at the model now, though, I see that I could just connect the front suspension levers together with an axle to put the bar up there, which wouldn't be very hard!

Sadly, this MOC won't be staying together long, because I need the parts for another MOC I'm working on right now!

Thanks for the reminder about chassis pics! I took those, and meant to post them, but somehow I forgot. Here they are:

 

Spoiler

 

48 minutes ago, gyenesvi said:

Great to see this build pop up now, I am just about to post my RC Toyota very soon :) Nice build, I like the drivetrain and suspension, especially the anti-roll bar, that is something I'd like to test in the future. However, I am not completely familiar with how it is supposed to work, I mean I get that it limits the articulation, but isn't that counter-productive? We want enough flex, no? In my builds, the flex usually is limited by the springs anyway. Maybe the anti-roll bar is less useful in that case?

The two buggy motor drivetrain is also nice and simple, I'd like to try that once in the future, but I guess I'd be okay with the speed from the slow output. With old diffs and planetaries, that seems to be plenty for me based on a previous build, at least using Buwizz motors and a Buwizz 3. Maybe these clone ones are weaker somewhat?

I think in general in Technic MOCs the anti-roll bar is counter-productive, because we definitely do want that flex! I think it was more necessary in my case because of the rubber band suspension I was using, which doesn't really have limits, and is very soft. Probably a suspension with springs wouldn't need them so bad.
Based on the tests I've seen, clone buggy motors are slightly weaker than original ones, and Buwizz ones are slightly stronger, so there probably would be a notable difference here. Maybe I just needed more speed to be satisfied, though!

[TexasEngineer454]

@2GodBDGlory, have you tested the carrying or towing capacity of the MOC yet? I only ask because I really like the rear axle set up and think it could be incorporated into a larger scale build for optimal towing/carrying. 

Also, did you notice any steering issues at high speed with the locked rear and open front differentials? 

[Teo LEGO Technic]

That's a sweet MOC!! I'm especially impressed by the speed it achieved, perhaps I should look into a similar power setup as well, as the physical remote is an improvement in my opinion over a smartphone touchscreen controller. The suspension is also an interesting approach and seemed to work very well, especially once you added the anti-roll bar. 

I'm excited to see your entry for the truck trial competition .

[Daniel-99]

59 minutes ago, TexasEngineer454 said:

@2GodBDGloryAlso, did you notice any steering issues at high speed with the locked rear and open front differentials? 

There is no easy answer to your question. It depends a lot on the traction of each wheel, wheel profile, wheel base, weight distribution, steering angles of a front wheels and the overall speed and other things.  If I would build a new car, I would test it with both open and locked differentials to see the difference in your particular case. 

 

[Daniel-99]

2 hours ago, gyenesvi said:

Great to see this build pop up now, I am just about to post my RC Toyota very soon :)

Spoilers, spoilers, spoilers ;-) Cant wait for it! Does it relate somehow with the new chassis you have posted today?

2 hours ago, gyenesvi said:

Nice build, I like the drivetrain and suspension, especially the anti-roll bar, that is something I'd like to test in the future. However, I am not completely familiar with how it is supposed to work, I mean I get that it limits the articulation, but isn't that counter-productive? We want enough flex, no? In my builds, the flex usually is limited by the springs anyway. Maybe the anti-roll bar is less useful in that case?

The discussion about row-bar usage is a small part of the car stability problem. With the Supercar it is well known that the suspension needs to be stiff and responsive. Road cars are build for medium speed, safety and comfort, so they need to have a soft suspension to deal with bumps, but at the same time they need an anti-rowbar for "fast" driving on the Highway for the safety reasons (in order not to fall off the road on speedy corners). Crawlers does not need an anti-rowbar for the maximal flexibility, but they are not pretending for the fast driving. The stability of SUVs is somewhat questionable to me, because SUVs should go both fast on- and off-road.

This problem is not widely-presented in Lego builds because most of Lego Technic RC SUVs are remarkably slow (under 9 km/h). On such speeds any spring suspension will work (especially if the springs are mounted to the live-axles directly). Currently I am working on a presentation of my new RC SUV and I will try to mention the stability VS off-rad performance topic there. As far as I am concerned, modern SUVs widely use electronics to have both stability and off-road capabilities. A  smart independent suspension (with pneumatic setup), ABS and several other electronic assistants replaced classic solid axles and mechanically lockable differentials. Sadly I can not use this Ideas in my Lego cars...

[2GodBDGlory]

1 hour ago, TexasEngineer454 said:

@2GodBDGlory, have you tested the carrying or towing capacity of the MOC yet? I only ask because I really like the rear axle set up and think it could be incorporated into a larger scale build for optimal towing/carrying. 

Also, did you notice any steering issues at high speed with the locked rear and open front differentials? 

No, I haven't tested that, and I don't think it would work well in this particular model, simply because the suspension is very soft, and not optimized for heavy loads.

I think the axle could potentially work for towing, but there's probably a bunch of things I'd change for that. Probably lower axle gearing with 12:28 or 12:36, and then I'd reinforce the bottom half of the axle better. Here I was trying to keep a lot of ground clearance, which limited the reinforcement I could do on the bottom, but I think a more towing-focused MOC could sacrifice clearance for strength.

I didn't have any issues with steering and my locked differential, but I also had an unfortunately low steering lock, so I didn't really anticipate any problems regardless of what I did with differentials! I think I could have gotten away with a locked front as well easily.

40 minutes ago, Teo LEGO Technic said:

That's a sweet MOC!! I'm especially impressed by the speed it achieved, perhaps I should look into a similar power setup as well, as the physical remote is an improvement in my opinion over a smartphone touchscreen controller. The suspension is also an interesting approach and seemed to work very well, especially once you added the anti-roll bar. 

I'm excited to see your entry for the truck trial competition .

Thanks! I'm quite liking the power and control of this setup, though it is a bit unwieldy to set up

[gyenesvi]

3 hours ago, Daniel-99 said:

Spoilers, spoilers, spoilers ;-) Cant wait for it! Does it relate somehow with the new chassis you have posted today?

Yes of course :) it is built on that chassis, so you already know the technical side :)

Thanks for all the detailed insights about the anti-roll bar, it does make sense. Things become quite different when one steps out from the world of slow lego motors/cars (crawlers) to the world of fast RC ones I guess, different problems/challenges surface..

[maicel]

very nice moc really like it