Daniel-99

Way cooler than the Batmobile !

Thank you! I will look forward to see your ideas about the drivetrain! With a FWD I cheated a lot by using custom hubs, which provide all suspension and steering geometry. Though I have another project in mind with independent suspension and planetary hubs, and there will be no way for me to cheat ;-) I understand why you would prefer not to use any custom parts, and I try to keep my solutions Lego-ish as well, but in some situation I have to use custom parts due to the practical purposes. I will definitely keep my Hornet in the garage for the future improvements. I agree, that both cable management and bodywork can be done better and I will work on in! Thank you! Exactly! Though they wont be able to compete with RC cars both in speed and durability. If I would need the driving experience only, I would have swapped from Lego to RC. But I really enjoy the development process, so I use Lego bricks but add some necessarily 3-d party components to make my cars alive.

I made a short introductory video !

Well, I made few attempts with lego panels but did not succeeded. The whole construction looked very bulky and it was hard to attach pannels to the bottom of the car since there is a half stud off-set under the differentials.. Also I did not liked how this panels stepped over the flat bottom... That is why i used plastic bottle to make a custom protection! NO GLUE is used, panels hold on the car by the inner tension of a plastic (bottle has a natural curve, and I used it in a smart way). As a result, bottom is almost flat, differentials are well-protected and no extra weight added! Who can do better? ;-)

Well done front page of the instruction! Though I would not use words "high performance" without performing us the driving tests in various terrain, jumps, bumps and so on...

Hey, @damian_kane_iv! Your question is very fresh and correct! Russian technic community is mostly based on Russian social media platform called "VK". There are 3-4 main technic channels, the biggest of which is Lego Technic Russia: (https://vk.com/technic_club). To register in VK you will need a valid phone number (I guess any number is okay, not necessarily russian one), after that you are free to join the group. Moreover some of Russian builders (Stas Revin for example) has Instagram accounts. It is worth mentioning that the English Technic community (mostly represented by Eurobricks forum) is a lot bigger than the Russian one! I don`t feel myself right to answer the question in general, but personally I build 4x4 off-road RC cars for the practical purposes.RC supercars in 1:12 - 1:8 scale do really struggle from bumps, which Russian walkways have a plenty of!

Thanks! I used Lego`s differentials in the Hornet, but also I tested Chinese clones. They have too much friction, but the problem can be solved by using Lego`s 12 gears. I will definitely protect the working gears in the near future.

As I saw in several projects one achieve a caster angle with lego hubs by moving lower suspension arm half a stud forward. This works with Lego hubs due to an admissible wobbling of plastic parts, but my custom hubs are designed for such off-set. And the kingpin is also achieved by a half stud off-set of the lower ball-joint. All together this allows me to achieve a good geometry easily. On the other hand, this wheels hubs are not than "universal" as Lego`s one. (Foe example, I would not use them in the solid axles). Thank you!

Yes, the beloved custom parts! The choice of electronics and the driving motor is great! ;-) Lol! I am a big fan of RC Lego creations and this boat looks very playable! Well done!

Hello Eurobricks! A few months passed since I shared with you my creations. Well, I was working hard on two RC projects and now I am proud to introduce you one of them! It is called "Hornet" and it is an Ultimate 4x4 Baja Buggy. Technical specs: 4-wheel drive, open differentials Full independed suspension Brushless motor, 3S Li-Po, GeekServo Custom wheel hubs with metal bearings Carbon-fiber axes, metal U-joints Transmission sits on the metal bearings Positive caster angle, kingpin inclination, Ackerman Anti-rowbar at the front axel 98 mm RC wheels understeering Light tubular frame A story behind the build. Half a year ago I bought myself a Brushless setup adapted to Lego. It can provide a strong and stabled stream of power to my RC Lego cars. In two days after the motor arrived I build a first project with it to test its capabilities. Of course, this was a buggy! The main goal was achieved, I was able to test the new system and it performed greatly! Though I was not happy with the car itself. It had technical problems with both front and rear suspension, steering, overview and proportions... During the winter holidays I found a great set of RC wheels on AliExpress. They looked ten times better then all the other RC wheels I had, so I bought them and at once started a new 4-wheel drive project (which will be revealed in my next post). All I will say now, it has solid axle suspension and no planetary wheel hubs. So it appeared to be quite fast and somewhat unstable due to the soft suspension and high center of gravity. I decided to postpone that project and build a fast and more stable Baja truck with the front in-depended suspension and the solid rear axle. The fist prototype can be seen of the picture below (half-way dismantled) and it looks totally weird, especially the placement of the Brushless motor! With such layout I tried to load the rear wheels, but did not succeeded. Despite a completely failed project, I get two important ideas from it. 1) My custom wheel hubs allows to build an advanced front suspension and steering with king-pin inclination, positive caster angle and Ackerman geometry. Also I learned how to use a half stud off-set for the attachment points of the lower suspension arm. 2) The placement of the Brushless motor behind the rear axle greatly load the rear wheels. I was not ready to give up, and decided go bigger next time and use my favourite 98 mm RC wheels. By widening the wheel base significantly I decided to solve the front wheel drive problem! It is well-know that steering rack is usually interact with a differential. Also the steering rack must be placed behind the front axle to achieve the Ackerman geometry. So I decided to move the front differential one stud to the front. The first sketch of the front axle looked very promising, so I decided to "copy" it for the rear axle. Well, to keep the same wheel base as at the front i needed to use the half-stud off set once again and this time on both lower and upper suspension arms. That is why the rear differential is covered with a mess of connectors and beams... Solving all problems with axles, I connected them together via central driveshaft and had to decide how I should place the Brushless motor. The problem is that the motor has a size of a PF XL motor, and so it requires a 24 to 24 tooth gear combination to connect it to the central driveshaft (and place the motor on a side or on top of the driveshaft). I was not happy with it because big gears would stick out from the flat bottom of the chassis. The brilliant idea came right in time! I decided to place the motor behind the rear axle and place the another driveshaft over the rear differential. This allowed me to use a 12 to 20 tooth gear combination! In addition it loaded the rear axle to achieve the understeering feature. It took me another day to finish up the first prototype, and I took the Buggy to an extensive driving tests. These tests took me over a month to complete, since they were interrupted with a melting of the snow. The following improvements were made (one by one): Reinforcement of the upper suspension arm. First version of the front suspension was falling apart on each big bump. Lowering of the suspension by one stud. This was made to increase the stability on the straight line and make the overview of the buggy closer to references. Also I widened the tubular frame for the same reason. Playing with gear ratios: differential swap and swap from 12:20 to 16:16 gear combination in between the driveshafts. Adding an Anti-rowbar with a carbon-fiber axe to the front axle. It was added to increase the stability on the fast corners. Making 3.5 L axes to solve the problem of the front U-joints falling off from the differential. The results. A tremendous efforts had been applied to finish this Buggy. A lot of hard work, tricky decisions and big regrets... Does the Hornet worth it? - NO! As a result I build myself a balanced RC car with a precise control, decent speed (about 15 km/h), enduring transmission and good-looking bodywork. But I would not suggest anyone to follow my way, because it will cost you a lot! If you want to get a good driving experience you would better buy an RC car! LOL.

Pure awesomeness!

Hey, Viktor! Your Bouncer is a great example of technicality and RC performance which I miss with a current technic lineup. Your B-models are great, but they bring certain limitation both in bodywork design and technical solutions. So this creation reveals your hidden powers ;-) Well done!

Hey! Good tests were made! And I am impressed with a max speed of your truck even with planetary hubs the motor made the car a fast beast! I wonder if your truck feels stable on a hight speed? I suppose that off-road tires and the lack of positive caster affect on the control. Does your receiver has an SVC system with gyro?

Yep, this is always good for RC models if you cover the bottom. Though it is impossible to 100% protect the transmission from the mud and dust (as it is done in real cars). Even with covered bottom, you will find some dirt and water inside your car coming from the wheels: mud from rear wheels will cover the car from the very back to the front end of rear wheels, while the front wheels (since you have AWD) will cover the whole cockpit. Thai is why I made realistic mudguards from a plastic bottle for my latest project (also my Falcon has a mud-protection in the front, to save the electronics from the flow of stones coming under the front wheels). Finally, even with all possible protections, regular dust will be a problem forever. I drove my cars on a dusty roads last summer and had to wash the whole car after each driving session. Such kind of dust is deadly for the plastic transmission. Yes they are, it is easy to find them and the quality is good. Also they are cheaper than the original parts. So they will serve well as plastic parts which need a periodic replacement. Indeed planetary hubs relieve the transmission, which will not happen with normal hubs. Also you have both big wheels and powerful motor, so I can not tell you if I it is possible to build a transmission strong enough to transfer all power from motor to wheels without planetary reduction. You will have to test it by yourself (though it is quite risky). What is the max speed of your trophy truck? I tried to calculate it from the video and it seems to be about 10-12 km/h. Such speeds I achieve with 1200 kv brushless motor and transmission with metal bearings.

I would say differently. It is possible to increase the ground clearance under the front axle by lifting the suspension (since it is independent). While the ground clearance under rear solid axle is fixed and require either bigger wheels or portal hubs to increase the clearance.

Hey! This is an interesting model indeed! Actually, it has several things is common with @Zerobricks universal 4x4 off-roader: Planetary hubs will last for long here, though they will fall into dust after extensive driving. In my builds I use Chinese version which can be disassembled and lubricated quite easily. Do you plan any future upgrades of your truck? I think it is worth upgrading the transmission with custom parts: metal bearings increase the mechanical level of a car dramatically from my opinion. Also if you are more aiming for speed and not for 4x4 off-roader, you might also enjoy wheel hubs with metal bearings (planetary hubs reduces the speed too much, and have a lot of unnecessarily friction). But this are only my thoughts, so keep up and have fun with your nice truck!

I found this video quite related to out topic:

1. I use carbon axles as well, they have been purchased at AliExpress. The quality is good. 2. I dont have the 3D model of the housing, and it`s designer sell only printed parts but not 3D models. I think this will be the best solution for Lego. Both hubs and beams will be great to use! Agreed! regular RC bring a bit of a mess into the cars. Though i love the fact that I can put components in the different places. It brings so much possibilities! Also it is easy to swap component to a new one, and upgrade your setup (it is easy to do since RC component are wide-spread). Finally, it is way cheaper than Buwizz products, and provide a lot more power. I wish they would do RC kits as well! Maybe we should make a collection of RC Lego cars to show the possibilities of the system, and after that contact CaDA.

I came to Brushless motors in the same way. Firstly I tried to power my creations with 2x Buwizz 3.0 units. They offer the best solution for Lego purists, and yes, Buwizz bricks (v. 3.0) are way more powerful than lego. But I was unlucky to drive into a garden pool, so both Buwizz units drowned. After an accident decided to experiment with custom Electronics, since It was way cheaper, more affordable in Russia and has an RC control system instead of Buwizz. I teated two different systems. First one is called "Leshy" it was not strong enough to power 2 Buwizz motors: batteries start degenerate quickly after I apply full gas (single Buwizz 3.0 unit has the same problem). Second system is called "WIxy" and they play a role of a RC controller for Brush motors (PF motors). This mighty units together with 3S Li-Po can give a plenty of power, but PF motors can not handle than much, so they start overheating of a full gas after 2 mins. This gives me the understanding that I should use a 100% RC setup to avoid any losses of power. I see. A baja truck made by @FriedlS is a very special one. It is rather small and light, so there is not much load in the transmission, not much load to the wheel hubs, so Lego parts could work here. If you are willing to build a bigger truck, you will have to deal with extra weight, and the weakest point here are the wheel hubs. I am sure you will build the car that drives good mostly with Lego parts, even in 1:10 scale, but you should be ready to swap some parts of transmission in between each ride. That is why I use metal parts (cause I am lazy) ;-) I think we should start a new topic all together with @FriedlS to discuss Brushless motor usage and related stuff. This way some other people might join our discussion!

Agreed! I am pleased with cars and do not need more. I love the bodywork of current lineup, but I am missing the functionality, a great example of such set is 42125 with a big hole instead of normal floor, interior and so on. Moreover I am frustrated by the technical solutions in the chassis. For example 42110 is a great set with many interesting functions, but it can not basically be motorised (in a straight way) due to the wobbling suspension arms. So I had to rebuild the whole chassis to get a working RC version of Defender. Current models are the great display pieces, but they are far from being technically and mechanically well-engineered. I am looking forward for the Lego sets developed by LPE Power (https://www.youtube.com/@nicjasno). Am I asking too much from Lego? But I am ready to pay for each brilliant technical solution is LPE`s cars!

Hi, @Krxlion! I have neither a qualification of an electrician nor any experience with RC cars world, and I started using brushless motors in Lego builds just 3-4 months ago, so do not judge me strictly if I am mistaken ;-) Melting axles is the first potential problem on a list. These problems usually happens one after another, so you will not face problem 5 on a least before you have not solved problems 1-4: Problem: melting axles. Solution: lubricate the transmission with a silicone grease. Problem: axle twisting. Solution: Build the drive shaft with axle connectors Problem: CV-joints and U-joints breaking. Solution: Use metal U-joints compatible with lego Problem: Gear cracking (especially an angular gear to the differential). Solution: tighten the connection with plastic or metal washers Problem: braking of gear connection points. Solution: unload the transmission 1) use planetary hubs (for 4x4 cars is the best solution) 2) Use 28:12 gearing in differential 3) Use smaller (and lighter) wheels 4) use a weaker motor The motor you use is way overpowered! One AFOL in Russia tested motors with similar strength in his Lego cars and it was impossible to overcome its power! Plastic transmission could not basically handle such power. I am using A2212 1000-1200 KV motors. They have enough strength to overcome 3 Buwizz motors. I mostly build fast cars with a total weight under 2 kilos, and this motors bright them to live easily, though I have to deal with problems 1-4. I can not tell you anything about Pinions, since I bought the whole RC setup from another Russian AFOL. He develops custom 3D printed parts for Lego cars. Here is a link to his original video: As you can see, he printed a planetary gear similar to one used in XL motors. So I dont have to deal with Pinions at all. Instead of that I have to lubricate gears regularly. If you will need some details from the video you could ask me for translation and explanation! After we get ourselves a right motor and solves all problems from the list, we should figure out our goals: what do we want from our Lego car with RC motor? My answer is the following: brushless setup beats all existing PF and C+ systems, the best ways to build cars with brushless system are presented by RC cars industry, but we will never achieve the same level of performance with Lego. My technical requests for Lego RC cars are the following: speed of 10-15 km/h for fast cars (like trophy trucks) and 3-8 km/h for 4x4 off-roaders. Faster cars will not survive crashes, and it will be very hard to control even with physical proportional control provided by GeekServo (due to the wobbling in the steering system). Slower cars are too boring to play with. Further, I wish to make my cars as durable as it possible. Here I mean not the durability of the chassis and body, but the wear resistance of transmission and Lego parts during regular driving sessions. To achieve the goal, I use custom parts with metal bearing made by few AFOLS from Russia. Also I lubricate all the gears which spin fast. Most important parts here are the wheel hubs with metal bearing since the whole weight of the car sits of this fast-spinning parts. I was lucky enough to buy a few sets of custom hubs both with metal bearing and metal U-joints adapted to them, so I can build FWD and AWD fast cars with them. For off-roaders, I am using planetary hubs from AliExpress, because they are not glued from the fabrics and can be easily taken apart, lubricated and glued into a single piece. Also they are wide-spread and cheap. For the next level of improvements, I use metal U-joints and carbon axles in the transmission, 5x7 frames with metal bearings (to install differentials), which avoid any cracking in the transmission. To sum up, extra power and extra speed requires many NON-Lego-ish solutions and it will cost you a lot. So if you want yourself a fast and durable RC car for every day, you would better by an RC car. But if you are looking for a serious development process, if you like test your cars and improve them to the max level, then this is for you! I wish a good luck to every person who is building Lego cars with Brushless motors!

By the way, when the planetary hubs appear, one made a modification of Madoca`s floating front differential with planetary hubs! (I will look for a reference, but i definitely sae several projects on YouTube). I think this modified version will fit greatly to Bronco (RC version).

Thank you! It seems to me that there is only a small group among AFOLs that enjoy brushless motors. Do you have any new projects with you brushless motor, by the way?

Rather unusual RC model. It is interesting to see how you managed to squeeze all electric components inside ;-) Though this car seems to be a little bit uncontrollable due to the fast gear and negative caster angel. Good experiment! I guess it would be cool to see two or three of RC models made from Monster Trucks racing agains each other!

Sorry if I am mistaken, but the designer of the front wheel drive of this type was Madoca! See, for example, his Dacoma: https://rebrickable.com/mocs/MOC-25520/Madoca1977/dacoma-4x4-redux/#details