Variteck

Hi everyone, I want to share this project with you: building a brushed motor-driven version of Didumos' Red Wolf. Of course, let me know if you think this is off-topic, okay? Since the Greyhound days, I've greatly appreciated Didumos's work: I think he's one of the best creators of Lego RC cars. I bought the Red Wolf instructions without having enough Buwizz and Buwizz motors yet, so I decided to start building a 4x4 drive system with what I had: a large brushed motor. I've long been passionate about using RC motors in the LEGO world, finding information online and following the Eurobricks forum "Brushless motors in the LEGO world - general topic." Introduction: While I tried to make the drive system as compact as possible, it's clear that miracles can't be achieved with such a large motor. Better performance and easier installation could be achieved with a brushless motor. For now, I had this one at home, and I decided to proceed anyway! Driving a similar model through an RC system (ESC, transmitter, receiver, 3S 11.1V lipo battery) offers several advantages over the Buwizz + traditional motors system, but this could be the subject of another topic. The motor I used is supposed to have a lot of torque (it's recommended for crawlers) and not much speed, but I think it's sufficient for a LEGO model. The transmission system begins with a 12-tooth Mod 1 metal pinion tightly connected to the rotation axis with an Allen key, followed by a 36-tooth gear that transmits the rotation to two 46490c01 planetary wheel hubs positioned in opposite directions. Up to this point, we have a reduction of about 15 times, which after passing through the yellow differential increases to about 23 times. To support the high rotation speed of the red axis, I squeezed a ball bearing between the arms and joints. It's a very simple and versatile solution, and I can't wait to put it to the test! Here are examples of other ways you might use this technique: I'm very pleased that I managed to maintain the 35 stud length from wheel to wheel! As for the steering, I had some trouble positioning the Geekservo. Due to space constraints, I couldn't insert the steering axle directly into the servomotor hole. Instead, I had to use a system of three gears spaced three studs apart, resulting in some backlash. I couldn't use two because I needed the axle crosspiece positioned vertically both at the start of the servomotor and at the end resting on the rack. I'd never thought of this, but this is impossible with two LEGO gears. Now the challenge is to fit the Red Wolf body to my modified chassis! If you like I will update you on the performances Thank you Didumos!

Hey everyone, I'm back with an update on my brushless trophy truck. I'm happy to report that after about 45 minutes of driving everything is working fine, no plastic parts have melted, and it's pretty fast! Short summary: - It's a modification of the original Goober Reboot trophy truck - Weight: 1,5 kg. - Width: 27 stud. - 3200kv brushless motor, powered by a 3S 11.1v LiPo battery, through a 45A ESC. - Red differential. - The transmission mechanism as a whole allows for a 29-fold reduction, including the approximately 5-fold reduction provided by the 46490c01 wheel hub. The only metal parts added to the original LEGO pieces are ball bearings to house the pinion shaft rotation and a few washers. In this photo you will see a 7x5 frame ruined by previous attempts: To support the high rotation speed of the axes I used the hole-in-the-hole technique that I have already described in this forum: the axles did not spin directly in the technic holes, but instead inside pin connectors that in turn spin in 1x2 stud housings, for example part 92907 (Axle and Pin Connector Perpendicular Split). In this way the friction is shared between the housing and the connector. The backlash between the rotation axes is really minimal and does not affect the final result. https://bricksafe.com/files/Variteck/trophy-truck-panoramica-/trophy-truck-aggiornamento/IMG_20251008_090618.jpg Here are two videos of the transmission in action: https://bricksafe.com/files/Variteck/trophy-truck-panoramica-/trophy-truck-aggiornamento/VID_20251008_091255.mp4 https://bricksafe.com/files/Variteck/trophy-truck-panoramica-/trophy-truck-aggiornamento/VID_20251008_091627.mp4 Soon I plan to install larger wheels (104mm tractor tires or slightly larger RC tires) and take a speed measurement!

Of course: all the damage reported is the result of a few minutes of use on the road. The photos I have inserted refer to the untouched rear axles, before the road test. Here instead is a photo relating to the damage to the central wheel of the differential. You will notice the 12t metal wheel of the MTP, the original Lego one had disintegrated immediately.

My truck asking me when it will be able to speed on the ground... I am testing 2 different rear axles, both with differential this time, reduction 1/18 and 1/14 approximately (this one with Didumos wheel housing). In the first case the differential is too weak, the central bevel gear wears out and the teeth jump, in the other version I obtained the fusion of an axle with a beam. Still working on it...

Thanks HorcikDesigns and Aurorasaurus. In the end, after extracting the Omega clip, I solved it thanks to my son's hammer ;)

Hi all. Can anyone help me? How do I remove the pin and make it pop out the other side?

Oops sorry I missed the final part of the post.

Great. Thanks Didumos. Could you give us some more details also on this type of tires and rims with possible references? In the meantime I'll start dismantling the Greyhound Buggy....

Speaking of wheel hubs: I'm working on fitting my 1,5kg Trophy Truck driven by brushless motor with Didumos turntables-based wheel housing . Has anyone ever tried it, have you ever tested their resistance at high speeds?

Good morning everyone. I have a question: I bought these two brushless motors with the shaft completely smooth, without grooves. How do you apply a gear to them?

Hi Didumos, great news! I think there are many of us eagerly awaiting your new project. But seriously, start by telling us what pieces we need to buy to be ready ;)

Hello everyone. Here are some updates regarding my brushless motor application project. After a test on an off road RC track with jumps my model suffered various damages: fracture of a rear wheel axle, front wheels ejected several times from their housings, and above all some elements of the transmission were irreparably melted, creating a Picasso of gears. https://bricksafe.com/files/Variteck/broken-parts/IMG_20241221_212448_edit_166444152809690.jpg Luckily the carbon fiber axle came out incredibly intact, and was able to be extracted. https://bricksafe.com/files/Variteck/broken-parts/IMG_20241223_212931.jpg I subsequently intervened with some adjustments: in particular I applied part 92907 (Axle and Pin Connector Perpendicular Split) to both ends of the second transmission axle, and I added a metal washer with a 5mm hole next to the 20-tooth gear (after having thinned it slightly with sandpaper). https://bricksafe.com/files/Variteck/hole-in-hole-technique/IMG_20241229_211108.jpg/640x480.jpg https://bricksafe.com/files/Variteck/hole-in-hole-technique/IMG_20241229_231233_edit_176602055156295.jpg I tested the trophy truck on the road again and was very satisfied with the result: the hole-in-hole technique worked perfectly and after several minutes of driving there was no melting. The 2L pin connectors were found to be perfectly free to rotate inside their housing, and the axle free to rotate inside them. I measured the speed of the vehicle with my old Honor 8 and a ffp2 mask ;) The overall weight (without the bodywork, and with the phone on board) was 1430 grams: with the ESC power set to 75% I measured a maximum speed of 21 km/h. The driving environment was not optimal, I think I can achieve even better results by driving in larger spaces. https://bricksafe.com/files/Variteck/road-test/IMG_20241229_110155.jpg/1280x1707.jpg I'm still working on the vehicle to get it ready to test at 100% ESC power, but so far I'm happy with it.

Thank you. I had thought about considering RC gears, but knowing the power of this beast of a motor I preferred to avoid contact between metal teeth and plastic teeth ;) Also, even though I'm a fanatic of power and speed, I wanted to limit the use of non-Lego components as much as possible.

Dimensions: 2838. Can you explain your advice to me?

It is my modification of the original Goober Reboot trophy truck. Here is the link to his presentation video: I made it two studs wider, made some minor modifications and above all redesigned the rear axle to accommodate the brushless motor.

Hello everyone, I am very happy to participate in this discussion group. I want to present my solution to make this 1.5 kg Trophy Truck run at high speed. https://bricksafe.com/pages/Variteck/trophy-truck-panoramica- It all starts with an 12-tooth Lego gear hooked up to a 3200kv brushless motor, powered by a 3S 11.1v LiPo battery, through a 45A ESC. The gear and motor are connected by inserting a plastic card into a 2L axle connector, and held together tightly by a metal drill depth stop ring. The mechanism allows a 17,5x speed reduction, including the 3x reduction provided by the Portal axle. https://bricksafe.com/pages/Variteck/2l-axle-connector The real challenge in taming the rotation speed generated by the brushless motor was to avoid melting the technic parts. In the first attempts, the primary and secondary axle support parts were guaranteed to melt or break. https://bricksafe.com/pages/Variteck/broken-parts The technic holes couldn't hold: holes within holes were needed. I then made a sort of linear bearing so that the axles did not spin directly in the technic holes, but instead inside pin connectors that in turn spin in 1x2 stud housings: cages with four walls capable of hosting 2L pin connectors or Liftarm Thick 1x1 plus Technic Bush 1/2 , depending on the case. In this way the friction is shared between the housing and the connector. The backlash between the rotation axes is really minimal and does not affect the final result. https://bricksafe.com/pages/Variteck/hole-in-hole-technique From the first road tests there is no evidence of melting of the plastic and no fractures, and the Trophy Truck can reach great speed: I am not able to measure it at the moment but from experience I can say that it is much higher than the previous version of the rear axle, originally composed of two buggy motors powered by 2 Buwizz. This is despite the fact that I conducted my tests with the ESC's maximum power setting set to 75%. Considering the nominal power of the motor, delivering all 11.1 volts of the 3S LiPo battery we start with 35,520 rpm, which become 2029 rpm after the 17,5-fold reduction: about 33 revolutions per second.

Thank you HorcikDesigns. How much is the speed reduction ratio?

thank you very much! I would be interested in receiving more information, for a long time I have been looking for a way to optimize the use of this splendid model of Didumos. so is it sufficient to connect the two central wires of the string of the PF connector? what is the esc? and how does it relate to the receiver? and speaking of the servant geek: is it a good product?

thank you. Could you give us more details about 10A ESC, and chinese RC transmitter and receiver products, and how you connected the PF l motors?

How are other of you facing the Pf servo motors shortage?

Thanks Amorti, that's just what I was looking for. I will keep informed about this new white hole motor.

Hi everyone. As you know, the PF servo motor (88004) is out of production and the units left on the market are reaching collector's prices ... Do you know a valid alternative product? I tried with a couple of different Chinese copies of the 88004, but in both cases the steering control is not gradual, but only has 3 positions (all right, center all left). Would it be possible to program a PF motor, like the M motor, with Brickcontroller 2 or similar products, in order to rotate by a defined gradation and then automatically return to zero? I mean in a similar way to what the 42124 does through Control +, which through software transforms a normal motor into a servo motor.

Thank you guys. I'll take a couple of Lego cables, and try to replace the damaged PF connector of the RC motor with a new one.thankk you guys.