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Found 30 results

  1. Hi ^^ I want to build 6x6 (first axle steering) trial uphill truck (outdoor fun in mountain) and i have two question. Tyres used: 107x44 (15038) Estimated weight: 2.5kg 1. Engine used I have 3x XL motor, and i think how design drive train: 2 or 3 motors drive all wheels (like normal car) 1 motor to front axle 2 motors to rear both axles 1 motor per axle Which will be the most effective? 2. Gearing I don't wanna use any gearbox, and i think about 3:1 or 5:1 (or maybee less could be too?) Thanks for help
  2. This gearbox is an upgrade of my ultra compact 8-speed sequential gearbox. The 8-speed gearbox was nice but it was frustrating to know that the 2-speed gearbox took as much space as the 4-speed gearbox. I thought about transforming the 2-speed gearbox into a 2+N+R one. I had an idea about how to transform this gearbox but I didn't really think about how to activate the reverse and the neutral. Maybe by doing something with the knobs... I spoke with @Charbel and he gave me the idea to use the Bionicle parts I already used on my previous gearbox. Then I ended up with this: I used large frames as in the Lamborghini Sian. They make the whole gearbox stiff and now you have just to build a chassis arount the 'box! The neutral was extremely simple to do. See by yourselves: The reverse was more complex to create. For every foreward speed, the 2+N+R-speed gearbox rotates the 4-speed gearbox by the red 16t at the bottom. The reverse doesn't use the 4-speed gearbox, it uses the blue 20t at the top of the picture below: To engage the neutral and the reverse, I fixed two Bionible parts on the left knob. So they act as a smaller knob, with two teeth, and at a point 1/4 turn of the right knob makes the left knob rotate by 1/4 turn, whereas for all the foreward speeds, the left knob does 1/4 turn every turn of the right knob. Reverse engaged: Neutral: First: There is a stop not to shift from the 8th to the reverse. The engine and the gearbox wouldn't appreciate. The wheels have to be connected the the red axle and the engine to the grey one. It's possible to use this gearbox for a 4WD vehicle easily since the red axle goes through the gearbox. With this gearbox you don't have to use a 8-speed gearbox and a DNR one anymore, as in the Chiron or the Sian. It saves space, and you can't engage the 4th speed whereas you are in neutral - all the speeds shift into a logic order. I will make instructions when I have time!
  3. (Warning: lot of text, dry theory and zero nice looking pictures ahead) Sorry for those horrible pictures - my phone from 2014 has a nice size but the camera is showing its age Whenever i see big and/or powerful model i wonder about the geartrain design, efficiency and reliability. I always assumed that it's better to transfer power with high rpm, rather than high torque. It took some time to figure out how to put this assumption to the test, but here it finally is: my geartrain testing stand V3.1: The idea is to measure the torque loss across the tested geartrain at a given rpm for a known resistance. Those measurements can then be compared for different geartrains. There are several challenges i had to solve and that still can be optimised - input is very welcome! Adjustable and reliable power source: i opted for a switching mode power supply on PF motors reliable torque measurement: originally i planned to get the input torque from electrical measurements on the motor and trust the brake's torque. Instead i built sensors based on differentials. rigid test-geartrain mounting: i think i used more 5x7 frames than 42055 but i'm still not satisfied (more on that in the results) consistent braking torque that doesnt change over time: i wanted to be able to run the testing stand for extended time, so no weight lifting or friction. Instead of an electric brake i opted for a fluid/air brake The assembly consists of: 2x PF L motors as power source with the added rpm sensor on a 1:3 ratio to get a better sensor resolution (from 20 rpm to 6,7 rpm) A rotating set of weight blocks on a 1:3 ratio as high inertia rpm-buffer The input torque sensor based on an inline planetary gearset and a lab scale The test-geartrain The output torque sensor The aerodynamic brake as power sink Let's take a closer look at the seperate modules: The power sorce are these two PF-L motors, as the brake is powerful enough to drive one motor alone into thermal shutdown - even without a testing geartrain. They are regulated by a switching mode power supply. Idealy i'd set the driving torque via the current (an electric motor's torque is proportional to its input current). My current-dial isn't nearly acurate enough, but fortunately those armchair-engineer thoughts don't matter in the real world As the rpm sensor only has a resolution of 20 rpm, i attached it with a 8t gear to to get a 1:3 ratio and therefore a 6,7rpm resolution (not visible in the picture). The inertia rpm-buffer was added because i had rpm oscilations, especially at higher torques. It's build from two weight blocks which spin at a ratio of 1:3 to store more energy (kinetic energy is proportional to rpm squared). This ratio is achived by 36t and 12t gears instead of the simpler 24t and 8t gears as bigger gears generally cause less bearing loads (longer levers with the same torque). They are hidden in the dual 5x7 frames to the left and right. To minimize the bearing losses of the weight block assembly, i didn't mount it directly in stud holes but instead layed it on four black discs. This way the weight lies on 8 holes (2 per disc) instead of 2 and has a lower rpm. Another advantage of this bearing system would be a way lower breakaway-torque, but that's irrelevant in this case. The torque sensors work by changing the direction of the roation and bracing the idler gears on lab scales. I built my own planetary differentials because they are more efficient than bevel geared differentials like those from lego and i expected a lot of torque. I had a hard time figuring out the angle between the gears so they don't have any preload. Then i realised that i could have made my live a lot easier by switching the 20t and 16t gears around The input torque sensor (red) is mounted on small turntables which transfer the force from the high torques. As the output torque sensor (green) only has to transfer the torque from the air brake, i mounted it directly on the turning axles to get more precise readings (no stiction from the turntable) The lab scales have a resultion of 0,05g up to 1kg, which is far to precise for this application. Here's a cutaway of the gears in the sensor. The input (red) and output (green) turn in opposite directions through the idler gears which are mounted on the yellow sensor beam, which then presses onto the scale. The tested gear train get's mounted in a big compromise of stiffness, space and removability. This part of the whole assembly has the most potential for optimization. For the beginning i made tests with a 3:1 ratio (power transfer with high torque) or 1:3 ratio (power transfer with high rpm). The power sink was the part of the project i experimented the most with, until i settled on this air brake. It's surprising how much energy it takes to turn those dishes. I can change the resistance by moving the dishes further inside, changing the gear ratio to the air brake, or change the dishes for some different airfoil. It has a permanent 1:3 ratio to provide some resistance even at low rpm. The size of the airbrake is also the reason i had to mount all the other components higher The connection between the modules is achieved with universal joints to prevent potential resistance from misaligned axles, the modules are braced against each other with two 5x7 frames: one immediately under the universal joint to assure correct allignment and one further below for torque transfer. Testing is unfortunately a pretty involved process: First i have to set the rpm via the voltage of the power supply (this can be a challenge even with the added inertia) Then i have to note the voltage, rpm and the min. and max. values on the scales manually. This is necessary (and difficult) because the scales have a high readout frequency and there's a lot of vibration in the system leading to readout variations from 2 to 7g. Then it's off to the next measuring point. I do this once with rising and faling rpm to prevent measuring errors by hysteresis. Automating this with a mindstorms system would be great but i have neither the sets nor any idea how to implement the torque sensors. First results showed that the variations in the testing runs with the same gear assemblies are bigger than the differences between the different gear trains I don't trust those results because of this (and because it goes against my intuition ) (green is the high torque transfer, violet the high rpm transfer) Now i'm not sure how to proceed. I could make more measurements in the hope that they'll even out eventually. Or rebuild the modules to be more stiff? I'm looking forward to your comments and helpfull insights
  4. Hello everybody! This is the first MOC I present on Eurobricks. My most popular MOC yet is the 3 speed auto gearbox ( But now to this gearbox: At first ask yourself this question: Which sense has a normal D-N-R gearbox in a manual technic car? It has no sense. It makes no difference if you are in the forward gear or in te reserve. But with this D-N-R gearbox it makes a difference, because if you are in the forward gear, you can not push the car backward and if you switch in the reserve gear, you can not push the car forward. If you want to build this gearbox into a technic car, you have to connect the grey connectors to the wheels and one of the black ones to the fake engine. For more information check out this MOC on rebrickable (maybe it is not approved yet): No I wanted to ask you, what you think about this D-N-R gearbox? Here is an video of my gearbox:
  5. After seeing @Sariel's post about the new 28 tooth gear, I created an Excel sheet that can be used to find the perfect (if existing), loose and tight fits between two Lego gears. It's only applicable to gears aligned along the same axis, so perpendicular and worm gears will not work - for now. Here is the link to the Excel file, located on Google Drive: I hope it's useful.
  6. I'm building a swinging ship to go with my amusement park. I'm trying to drive the thing with a large rubber tire underneath it, but I'm out of my depth when it comes to gears. I need the wheel to spin clockwise for a few seconds and then switch to counter-clockwise. I have tried using a power functions switch, but without enough momentum to flip it, it always gets stuck in the middle off position. I tried using the remote and the IR sensor and manually controlling it, but I'm running my PF motors off of the old 9V train controllers, and there isn't enough power that way to run the IR sensor. I don't want to go with batteries. I wish there was a wall power option for the PF product line, but there isn't. So now I'm trying to create a gearbox that periodically reverses direction, but everything I've tried is close, but not quite there. Does anyone have the know how to create a gearbox that reversed the output direction every 2-4 seconds?
  7. Hi!My name is Atilla from Hungary and I'm new to this forum. I have been lurking for a while, mostly reading the splendid pictorial reviews. Lately I decided to start a blog of my own, something between the mentioned reviews and Blackbirds technicopedia, displaying the sets I own.I have only 1 post so far, and I would like to expand a bit on that. (If somebody is interested, I can post the link to it. I'm not sure whether it counts as advertising or allowed at all).I'd like to ask for help with my research for an upcoming post. I'm writing a review of the first supercar, 853, and I would like to have a section of the history of the Technic product-line in the review.Here's what I know:I found, that the first Lego set ever to include any sort of gear was the set number 001, released in 1965. These gears did not have the X shaped hole in the middle, as the first axle with a X cross section wasn't released until 1970. Then a new set of gears was released, very similar to the previous ones, which now included the X shaped hole. These gears was not compatible with the Technic gears at all, because of the different teeth profiles.I also know that that the first universal joint was released in 1972, it was very similar to the Technic ones, but in a different colour (i believe red).This information, I could pull from the catalogue of bricklink, and some youtube videos reviewing the 001 set. I managed to buy some of these early gears from bricklink, in order to make a few high resolution photos. I'm aware that there was an ideabook (managed to buy get hold of it), showing 853 with a yellow body, made from the 852 helicopter (which I also managed to buy). I found that there was an image in the back of the building instructions for the set 858 "Auto Engines", showing 853 with an engine in the back. I managed to source 858, but could not get a building instruction for it. Fortunately it can be found online. I'm planning to build these "official" modifications as well. and take pictures / incorporate them into my blog post. I humbly ask if you could provide any more information about what similar functionality was present before the release of the Technical Set line in 1977. I'm aware of the "Dacta" line, but as far as bricklink knows, there was no Technic related Dacta set until 1983. Maybe there was other Dacta sets, using the pre-technic gears, but I couldn't find them. If there is a thread of a blog on this subject which I missed, then a link would be welcomed too.Any input on the subject of what lead to the release of the first 4 Technical Set is greatly appreciated. Thank you for reading my post.
  8. Hi there, I've noticed whilst testing 'Electric Technic Motor 9V Geared 480rpm' (47154), it was making a strange buzzing noise whilst going both clockwise and anti-clockwise. Could this mean one or more of the internal gears are failing? Thankfully, there are four thin screws on the bottom which allow the motor to be taken apart. Are replacement gears obtainable? If not, then I have to have them either 3D Printed or cast in a silicone mold. Thanks.
  9. I don't know if this has been shared before, but in cases where max precision is more important than min friction, it may help to route gears double (with equal ratios of course) and have the closed circuit skip one or more teeth somewhere in the circuit. That way you can have the slack in one route compensate for the slack in the other route. When you route gears double, the gear meshes together make a closed circle. Before installing the last gear in the circle, you can sort of wind up the adjacent gears against each other to eliminate slack in the rest of the circle. Now when you install the last gear while the adjacent gears are wound up, you get a closed circle with only very little slack in it. With the number of 'skipped' teeth I refer to the number of teeth by which the adjacent gears have been wound up, compared to their positions without wind-up. In this simple circuit I skipped 1 tooth to obtain a transmission with practically zero slack:
  10. Hello, I've been building with lego technic for a couple of years, but found myself never having the right pieces for my builds. I recently bought a second-hand lego set with some nice wheels (8386). So I could finally start building some bigger and cooler cars. I started with my first supercar this week and am having trouble with the rear axle. I am using the method you see in this picture ( with 2 separate axles. The problem is that I want to use a differential, but can't figure out how that would work with this. Does anyone have a solution for this, or does anyone have a different, stable (compact) method for this? Any rear axle that has suspension is welcome. I would appreciate it to see more ideas from you. One more thing to keep in mind is that I only have the type of universal joints you see in the picture ( I don't have any other. Thanks in advance ;)
  11. I said before in my previous post that I had some problems with my GX EV3 4x4 chassis that I needed to fix. Once again, it's more gear grinding/clicking, but this time it's only in the front and rear differential gears. The grinding occurs whenever the chassis tries to drive into a wall or when it tries to drive in different conditions (because as an SUV it should drive smoothly in dirt or uneven terrain). What also annoys me is that when I push the car, instead of letting the motors move, the differentials make clicking noises that, like I said before, sound like a machine gun. I really need help so I can stop the differentials from clicking so when the car tries to drive into the walls, the motors won't still move while the differentials click, and so the car can be a lot more versatile on uneven terrain (such as what I used for testing, blankets) without the differentials causing a problem when the car moves. Here's some pictures of the bottom of the chassis.
  12. I'm back again with another gear grinding issue but this one is a bit less critical. The grinding only occurs when my 4x4 SUV chassis (with Sariel's 4-Speed Sequential Transmission) is in a certain gear. Here's some photos of the chassis. The transmission is shifted to the speed where the nonstop grinding occurs. When in this gear (I believe it may be 3rd) The car is supposed to move, but it does very slowly while clicking noises fire like a machine gun. This is the only time when the gears grind other than, say, if the chassis hits a wall. When the clicking begins, I hear the driving rings shake (which awfully reminds me of the somewhat gear clicking in the Mercedes-Benz Arocs set). I would love a response a soon as possible to address the clicking problem so I can finish the chassis once and for all.
  13. This is my second post on the EuroBricks community and another question asking for as much help as I can get to master the art of the technic gearbox. Like I said in my previous post, for my Lexus GX EV3 4x4 SUV, I tried my best to use Sariel's 4-speed sequential and it ultimately failed on me. Quoting one of my replies... I would be relieved if I could finally finish this creation after five months of difficulty. Here are some pictures of the entire chassis. I said before that the issues with this was that the gears clicked a ridiculous amount at the highest gears which stopped the car from moving. (Hence the reason why the transmission I want needs to have a clutch gear to absorb the large amount of torque)
  14. Just wanted to preface this by saying I am a complete noob when it comes to engineering and HATE asking others for help with homework. However, I desperately need help in my engineering class to maintain my high honor roll grades. I need to come up with a comprehensive design by Monday and have been procrastinating for the past week. So the final of the class is to design a rover with four wheels that can drive through the obstacle course (It's basically a turn and a hill). The requirements of the rover are: Must "stand" on a cardboard platform Use 2 motors Have at least one worm gear have a mechanical advantage between 72-120 using LEGO gears must have "vertical" axles meaning the axles go from the front right wheel to the back right wheel and the same for the left. Must be less than 9in by 9in including wheels Can only utilize worm gear, 8 tooth gear, 16 tooth gear, and 24 tooth gear although using a differential or whatever it is called is also ok. have wooden structural pieces that strengthen the chassis The motor cannot be glued down Must be able to turn while "stationary" by having wheels on one side go in reverse and the wheels on the other going forward. Thanks for the help everyone! I'm sure you guys think this is really basic but engineering really is not my forte.
  15. I'm building a SUV drivetrain for my Lexus GX EV3 project that has independent suspension, four-wheel-drive, and a four-speed gearbox with a medium EV3 motor that shifts the gears. Unfortunately, after testing the drivetrain, I found that when in 3rd or 4th gear, the gears make a clicking noise when moving forward and then straight to backward. However, this clicking somewhat occurs less when going from reverse to forward. This clicking really "grinds my gears" and I don't know what to do to stop the gears from clicking. My gearbox is a custom version of Sariel's four-speed sequential that is fit for the vehicle I am building. The input in the transmission is switched to provide more speed. Two large EV3 motors drive the input. I've noticed that when the vehicle stops, it goes the opposite direction for a little bit. Also, like I already said, this clicking only happens in 3rd or 4th gear, but mostly the 4th gear since it brings the most speed. I tried to solve this clicking with different gears and whatnot, but no matter what they still clicked when the vehicle moved forward to backward. The motors and the gearing also bring a lot of torque as much as it brings speed, and this might be one of the problems. Is there any way I can solve this issue so the gear clicking will stop in this situation (moving foward and then straight to backward) for now on? Here's a photo of the bottom of the drivetrain. Thank you in advance for any assistance that you may be able to provide!
  16. I got the Bucket Wheel Excavator in September last year, and after building it and modifying it (with Mindstorms), I dismantled it to use the pieces in my other Mindstorms creations. I'm particularly interested in the large yellow planetary gears/rings that come with the set, I hope to use them to create some sort of tank with a rotating turret. However, I'm not too sure about the geometry of the pin-holes in the rings, I don't really know where it is safe to attach a pin in a certain hole. If anyone knows of the correct geometry of the rings, it would be very helpful!
  17. After a little tinkering, I managed to create this self-locking differential. It locks when the car goes straight and unlocks when turning: A set of 12t gears are connected to the steering rack. When the rack is in the middle (and the car going straight), the two halfshafts are coupled together, locking the differential. When the rack moves to the left or right to steer the car, the 12t gears disengage with the 20t gears and let the differential act like an open diff: The main downsides I see with this setup are that the differential may stay locked during wide turns with small rack movement and the width of the axle is increased. A standard independent suspension with a differential and 68.8x36 ZR wheels (the combination I usually use) is 25 studs wide; with this feature it increases to 27.
  18. Any tips on ways to put it in and use it with nly a small amount of space? * I meant only
  19. The new gear rack quadrants have other possible uses for Technic builds such as:- 1/. Bucket Wheel trencher ( BWE - C -model ? ) 2/. Large crane builds. 3/. Fairground rides - not often made using Technic. 4/. Railway Hopper wagon coal / iron ore rotary tipplers What else could these gear quadrants be used for ?
  20. I am looking for some suggestions. My daughter is building the Mars Rover set (go here for the details: for a presentation at school and I told her I would help make it operate by remote control with one of the power function kits. Problem is that it is a lot more complex than I thought. (I have no experience at the expert LEGO building). I think I can maybe get it moving with a remote, receiver, and simple motor attached to one wheel, but I do not have any idea how to do the steering and don’t know how to move any of the other functions (camera, antenna, robotic arm). see It was not designed to be converted to power functions / motorized. Here is a photo of the underside: I am not sure the easiest / best way to add power for drive and steering. It just has to move a little bit in the classroom, not drive outdoors in all terrain. I posted in another forum and a member suggested that I post here. Any suggestions to help me figure out what I need to do and what to buy to easily make this work would be much appreciated. Thanks much!
  21. I need suggestion with my car. I have images below of what I have so far. A few questions. What springs should I use. Hard or soft? What wheels or tires? And I need ideas on how to complete it. So far my axle has working steering and a driveshaft connected. I don't know what to do next as I am a new technic builder. If any more information or pictures are needed please tell me :) Images:
  22. I have not been happy with the performance of my 9396 for a long time, so I am in the process of rebuilding it. The issue is that both the manual and motor-driven operation of the blades are sluggish and involves seemingly high torque, perhaps due to the large number of gears in the drive train, resulting in very slow turning blades. After completing about 82 steps in the rebuild, I got to a place in the build in which I can turn the blades with the hand knob, and again there seemed to be a lot of binding and "stiction" of the gears, which I traced to the gear directly driving the turntable being the primary trouble maker, highlighted as lime-colored in the LDD image. Loosening the build at this location, by forcing the two DSG11L beams slightly apart, resolves the issue, but is not a permanent solution as these will be tightly locked in place once the build is done. Does anyone else have similar issues, or suggestions to fix?
  23. Hi guys, I have been trying to make some trains (generally diesel) and a problem that I have always found is powering. for a steam locomotive this is usually pretty simple because of the lack of articulation but wel, bogies are articulated and motors are mounted in the build itself. my question was, how does gearing react to this? and what is the handiest for compact solutions? vertical or horizontal? with vertical you get this: lego 6L train bogie by alterlegotechnic, on Flickr how could something like this be used in a locomotive? would the motor stick loosely in the chassis and what about a vertical motor like this (http://www.brickshel...16/cam06194.jpg) will there happen something in corners? like that the would go faster or some? and with Horizontal you get this Iowa Pacific SLRG 515/518 Mechanics by wildchicken_13, on Flickr how can gearing do this? i mean the rotating bogie, what happens to the gears in it? obviously could 2 M motors be needed for a small train (around 4 cars) or will it fail? I heard something about a V2 receiver? I have a V1 (I think) and that a normal one won't be able to give enough power to both? What is better? XL or M? when will a XL be needed? so in one sentence: vertical or horizontal? what happens to gearing and what is easier when using normal motors?
  24. AyliffeMakit

    [MOC] L'Supervivere

    L'Supervivere Over the course of several years during the great industrial age, this mechanical suit was created by the lesser-known Professor Stewart Phoenix out of disused parts scavenged from various scrapheaps and abandoned factories around the outskirts of Victorian London, hence L'Supervivere's rather cobbled together and unusually complex appearance. The original and sole purpose of L'Supervivere was to be used by Professor Stewart Phoenix to protect his family and his estate, Phoenix Manor, from destruction, but over the years this technical monstrosity was also used for several other suitably vital causes, such as fixing leaks in the Manor's roof and rescuing cats from trees. The most notable alternative use of L'Supervivere was during a lengthy voyage abroad, in which it was used to navigate the treacherous rainforests of the Amazon and defend a party of explorers (including Professor Stewart Phoenix himself) against any threats they may have encountered. At the end of Professor Stewart Phoenix's long and fruitful life, he proclaimed in his last will and testament that L'Supervivere would be passed down to his eldest and only son, Dr Joseph Phoenix, on the sole condition that it mustn't be used for any type of criminal activity and that at the end of his life, he should also pass on L'Supervivere to his eldest son, and that this son should pass it on to HIS eldest son, and so on until what is only described within Professor Stewart Phoenix's will as "The end of all days", but so far no-one has been able to fully understand the meaning behind this choice of words. Mysteriously, after being passed down through several generations L'Supervivere and the Phoenix bloodline completely disappeared from public view in the early 1920s. It is still rumored that L'Supervivere still exists in its original form to this day, but the location of the suit itself and it's rightful owner is currently not known... More images on my Flickr. Enjoy!
  25. Here are couple videos shows how to make velocity that varies, but remains constant over longer time. Very simple setup. Rotation with intervals. There is small chance that gears stuck. A-axle connected to motor and rotated with constant speed. B-axle connected through chain. Part time of cycle rotates faster, part time - slower. Both axles do full cycle in same amount of time. In both cases i attached axle to a gear in non-standard way. Attaching axle by different angle (but same place) will move center of rotation closer to gear side by 1 mm. You could place axle-pin to that place to fixate another axle in one of 4 holes of that gear. This gives another alternative for speed and position The only problem - I haw no idea where to use this approach :D So let me know if you used it anywhere.