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Showing results for tags 'pendular'.
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Universal 4x4 off-roader
Zerobricks posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This model (and it's prototypes) are a result of the following topics: Basically the idea behind this project is to make an offroader capable of driving on all kinds of terrain with a simillar perofrmance as the Wildcat 6x6 but having a lower weight So, why would I want to reduce the weight? While the wildcat 6x6 works great most of the time, it's high weight of 2,5-3 kg has some drawbacks: The model requires a lot of expensive electronics (12 BuWizz motors, 6 BuWizz 3.0 bricks) High part count (1869 pieces) Tendecy of front wheels falling off at hard landings High wear and tear of the individual components, which lead to premature failure - planetary hubs, CV joints And lastly high wear and tear of the handler due to it's heavy weight Of course decreasing the weight also means decreasing the power to weight ratio, since there will always be components which are needed regardless of the number od drive motors like wheels, hubs, steering system, suspension and frame. The first protoype, which I simply call Light 4x4 used only 2 BuWizz motors coupled to a 2 speed gearbox: While the model worked good in low gear, the high gear proved much trickier. The single gearbox put a lof of strain on the drive axle in high gear, causing it to melt, even with lubrication. Another issue was the high load of the motors in high gear, resulting in them overheating, while the motor could not even remotely apporach the 15 km/h top speed of the Wildcat 6x6. But not all was bad, I really liked the free-moving front suspension which acts like a suspended pendular axle, while having a much lower unspring weight. While I could make the rear suspension act like a pendular axle instead off front, i decided agaisnt it, since most of the weight is shifted back when crawling and I wanted to keep the rear stable. With that knowledge, I went back to the drawing board and decided to up the power for the next version... Medium 4x4 prototype: This version used 4 BuWizz motors coupled in a manner simillar to my 1:10 Acura NSX which negates the sideways load on the output axle of the gearbox. As you can see, this version was quite bigger and it used the reinforced differentials. The increased power drastically improved the performance, the top speed and overall power being simillar to the Wildcat 6x6. BUT the model had a few problems, main being the exposed gearbox which would get clogged and jam while driving outside. This version was aslo wider compared to the first prototype. Medium version prototype 2: This is another concept where the entire front axle is designed to pivot, but I ultimately decided to go agaisnt it due to the higher center of gravity and higher unspring mass. The final, universal 4x4 model: I have built and tested the model, but have yet to make any media, that's why I'm using LDD photos for now. I had to way to make the model more ingress resistant and narrower. This is where I came up with the idea of using the new, reinforced differentials as 28 tooth clutch gears for the high gear of the gearbox: This way the gearbox's output axle was moved a stud lower, allowing me to cover the bottom of the model with panels which prevent the dirt from getting into the gearbox without sacrificing ground clearance: The model inherited the front axle from the prototypes which acts like a free pendular axle. This keeps the weight even on both side of the suspension sosimple open differentials sufficed without a need for lockers. The gear ratios are a bit of a compromise comapred to the Wildcat 6x6, with low gear being 0,89x the ratio and high gear being 0,83x the ratio. Even with these differences, the model still reaches a very simillar speed in high gear, probably due to lower friction losses and lower rolling resistance. All in all I think this is a worthy successur to the Wildcat 6x6, even though it may not be as flashy, massive or functional (no skid steering). Final part count is 774 pieces which is 41% od the Wildcat 6x6 and the weight has been reduced to around 1,4 kg - around half of the Wildcat 6x6. I will be creating a proper in-depth video about the finished models and the protoypes, so I suggest you to watch this space for more upcoming details. -
Here's a model I actually completed a year ago in order to be unveiled in time for the BuWizz picnic back in 2021, but we all know how things went... Anyway since the picnic did happen last weekend, I decided to unveil my most powerful offroader. The basic design is based on the Wildcat 4x4, but this version adds more power, a 2 speed gearbox and a third axle to the formula. As with the older version, each axle has independent suspension, plus the entire axle can pivot or swing, effectively giving this model double suspension setup. Indepedent suspension is great at absorbing small bumps when driving quickly, while the axles pivot along the terrain when crawling. The driveline was quite a challenge. In order to transmit the power from 12 motors to the wheels, each wheel ended up having it's own dedicated 2 speed-gearbox. The final driveline is extremely compact and efficient, with only 3 gears engaged at any given time. There are also no differentials or perpendicular drives, so nothing that can break or skip. Each gearbox is actuated by a PU M motor using worm gears, which prevent any unwanted skipping out of the gear. This way each wheel is powered by 2 BuWizz motors via a dedicated gearbox: The following gif shows how the front axle is designed along with the whole model: Here you can wee, how the front axle tilts in order to adjust to the terrain: The rear axles are made in the same way as the front axles, minus the steering. Rear axles are also designed to work in tandem, when one goes up, the other goes down. When one tilts left, the other tilts right. This way the rear suspension is extremely flexible: And finally here are some specs of this beast: Length: 52 cm Width: 26 cm Height: 20 cm Weight: 2,5 kg Top speed: 15 km/h (rounded up) To complete the presentation, here's a video of the model in action, a big thanks out to @braker23, @Sariel and @kbalage for the footage. Final thoughts... this is my most potent offroader to date. The sheer amount of power, torque and speed is hard to wrap your mind around for a model made entirely of small plastic pieces. Having said that, I think there are still few areas to improve: Tendency of the front wheels to fall off at hard bumps - A lighter version would help to reduce stress on the hubs and wheels. Could use a higher steering angle - Would have to find a way to integrate steering racks inside the transaxles. Protection againt depbees and dirt entering the drivelines - Something that would also not reduce the ground clearance, tiles might work.
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[MOC] Mercedes Uniknick Trial Truck
Teo LEGO Technic posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Hey everyone! I'm back with a pretty simple design: a Mercedes Uniknick trial truck. It's inspired by this guy: https://www.youtube.com/watch?v=VEsdl_dPoZk The functions are straightforward: - Steering with L motor and two small actuators -Power with 2 XL motors and no diff's -Steering is a turntable at the centre of the truck -PF LED lights -BuWizz power Here's the video and some pictures. Again, it was just a simple build, but the final performance and look was pretty pleasing to me :) And the reference: More images at my bricksafe: https://bricksafe.com/pages/Teo_LEGO_Technic/mercedes-uniknick Enjoy guys! -
Hi everyone This is a model i built a while ago, but only now had the time and eqiupment to showcase. I was asked to build a Buwizz showcase model for a toy fair in Boogna, italy. After some thought I decided to combine the rare dark blue panels from 41999 with tracks and a couple of RC motors. The finished model has following features: 2 RC models for drive Spring supported pendular suspension Two working fake V8 engines - hence the V16 Rollcage reinforced interrior with 4 seats Openable 70's muscle car style openable bodywork A working winch LED bar powereed by a total of 10 LEDs So lets start with a 360 view of the model: As you can see the body is inspired by 70's muscle car styling with large chromed grill Detailed view of the grill with the cute bunny: Lifting up the body exposes the internal rollcage and the two massive engines: Further the rollcage can be lifted by pulling out the two red pins, showing the 4 identical seats, making this a perfect family car The two V8's are powered by the RC motor's faster output: The power passes via cardan axles under the seats and up the gears: In case the model ever gets stuck there is also a functional winch powered by an M motor via 1:5 gearing ratio: The suspension is highly flexible: And here is the most important photo of any technic model : And to finish up with a bang here's a video of the Ripster in action: A quick summary of my thoughts regarding this model: Because the tracks are powered by the RC motors directly this is THE fastest tracked model I ever had the pleasure of building. But that speed comes with a price, the model has problems steering on spot on surfaces with high friction such as carpets. Sudden acceleration on such surfaces with quite a heavy model like this (1,5 kg) can cause problems with tracks coming apart. For that reason this is a perfect vehicle for smooth surfaces or ice. It is also very good at drifting, though it takes a lot of coordination to control a tracked vehicle like this. Suspension is extremely durable, the wheels were originally held with frictionless pins, but that proved insufficient, so they were replaced by axles 5 with stops. After that upgrade I had zero issues with suspension and it proved to be very flexible, yet reliable. Biggest problem with the model is the cosmetic stuff, the V8 chains tend to slide off after a while at such high RPMs, the bunny likes to jump into oblivion and the front grill can fall apart when crashing into stuff. Oh and one last thing, ITS LOUD. Driving this on my floor sounds like machine gun fire, so I hope my neighbours wont file a complaint . At the end of the day even with its positives and negatives its a very fun model to drive around and that is all that matters.
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[HELP] Building a Truck
BuildSnapPost posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Please Help me! I am making a LEGO truck, and I was wondering whether it is possible to build a vehicle with two suspensions like this. : 1. https://www.youtube.com/watch?v=b_bN7rFMjaw 2. http://sariel.pl/2010/11/steered-suspension-for-heavy-trucks/ Firstly, would it work if I have two of these style of suspensions and; Secondly, would it work if i have them without shock absorbers to return the wheels level in reference to the vehicle. Thanks, BuildSnapPost. -
[MOC] Mercedes G-Class SWB
Teo LEGO Technic posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Hello everyone, Here's my newest MOC, a Mercedes G-Class. After months of hard work, and bugs and fixes, it's finally finished. It was built to incorporate all of the best elements of high-torque gearing with a compact bodywork. It features: -Drive - 2 x XL, geared 4.5 : 1 -Steering - 1 x Servo -Lights - 6 x LED with hidden switch -Suspension - pendular A video showing all features: Pictures: -
Pendular shock absorbers
Junpei posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
It always bothered me that pendular suspension can only (?) work with rubber bands, and I really don't like rubber bands, I am not sure why, so when I coincidentally broke the seal on a pneumatic actuator, I made this: If there are two of them mounted on a pendular axle , when one compresses, the other one stretches. This allows one stud of travel both ways as the fully compressed spring takes up one stud: Fully extended: Does anyone think this is a good idea? I would like to have pendular suspension with shocks but the compressing and stretching shocks may just take too much space. Anyone feel free to add your opinions and criticism. -
Suspension Help?
MrNumbskull13 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Hello again, I have recently downloaded LDD and started building a pendular suspension set-up. My only problem is how should I transfer power from the main chassis to the pendular axle? Should I use Zblj's idea where two double bevel gears are meshed together (shown in one of his trial truck tip videos, I think it MIGHT be number 3 or 4...) Or should I just put in a rod that goes through the pivot point. Sorry if it's hard to understand - that's the best I could explain it. :/