AutoBacon

Eurobricks Vassals
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Everything posted by AutoBacon

  1. Awesome build. I love how clean it is :D
  2. Looks great, small and compact but not flimsy. Do you have a stud.io file for it? Can't see how you hooked up the steering motor in such a tight place :D Also can't see how you won't win the next 56mm truck trial :D
  3. Nice work on the front axle. It's interesting working at these small scales, there are only so many designs because there is such little room for excess parts, yet there is always someone to take an idea and make it better :D
  4. This is awesome! I'm wondering if test units will be available for order :D The all in one package looks good for small models, mini crawlers and such. I was wanting a buwizz but I think this is an even better option!
  5. Greetings. I would like to present my first completed model; a small-scale remote-controlled pickup truck. Featuring 4x4 drive, 3-Link suspension front & rear, 7-stud wide axles, no old-style CVs, and a fully modular body/chassis. I had a few goals with this project; Produce the smallest possible scale 4x4 whilst retaining realistic proportions Use as few parts as possible System body for detail and smoothness This project began as a test platform for an improved 7-stud wide driven front axle design taken from my WIP KrAZ project I started last year. I wasn't happy with the unreliability of old cv joints, and weak rubber-sprung axles, so I embarked on a quest to fix these issues. I realized I could fit new CV joints after seeing @apachaihapachai's Terracotta Pickup Truck, this massively improved the load capacity and reliability, while making the overall package smaller, making me confident the axle was now strong enough to support a brick-built body. Next was the suspension, I needed real springs instead of 45590 rubber pieces. After some pondering, I discovered that I could take springs out of regular shock absorbers, and keep them in place with ball joint pins. The suspension now had great support and range of motion. I made the rear axle with as few parts as possible, it flexes a little but it is strong enough to handle a small model such as this one. I wanted to keep it as simple as possible to keep the level of bulk to a minimum. Below is the final chassis. Because the axles are only 2 studs high, the chassis can be nice and low, while still giving one stud of vertical suspension compliance. What I found with really small models, is the motors tend to get put in strange places and often become structurally integral in order to keep the model small. To keep with the ethos of this build, I wanted the drive and steering motors to be concealed within the chassis rails, while also being easily removable, and using the fewest gears possible. The result is a drive motor/transfer case with an integrated steering motor. It is mounted directly to the chassis with just 4 pins. The model is powered by a MouldKing battery mounted in the cargo bed, feeding power to the L motor for drive, and Cada micro motor for steering. The final drive geared down 1.67:1 from the motor, and with a total weight of about 650g, this gives a good mixture of torque and speed. The Cada micro motor is slow enough that it can be used to directly drive the steering rack, as long as you have a proportional controller. As well as the suspension solution, there are a couple of modified parts; namely a shortened suspension arm with tow ball for the rear axle, and a 2L half-thick liftarm to improve the front drive input shaft rigidity. Regarding the body design, I decided to try using the new wheel arches from the Camero set. I hoped these pieces could result in a body that wasn't outrageously heavy but still had a good level of detail. I needed to keep the design simple as this is the first time I've created a body, I don't usually get past the chassis in my builds. The proportions and style of the design were based loosely on a 70s Chevy k20, although the arches are a little too big. I ended up liking how the side panels could be removed completely in one piece each, and the rest of the body plugged into the chassis with 2 pins per section for easy removal. Anyway, thanks for reading, any feedback regarding the build/presentation is welcome. Check out the video for a closer look and to see its capabilities with some outdoor driving.
  6. Interesting, thanks for the insight. I wonder now if a linkage system at this scale would offer significant improvements, it seems it would just put more stress on the motor and be less precise than a rack and pinion. I'll have to think about it and do some tests :D I originally used the tractor tires before the RC4WD ones arrived, along with stiffer springs to mitigate wheel rub, and it is true it looks quite good the way they stick out from the body. I agree that perhaps 9 stud axles with custom tires would look pretty good and provide more stability. I'm thinking now that this kind of implies that the body I created is slightly too big, and could so with shrinking, to get the same effect, which would require the omission of the windscreen piece and the wheel arches, as they kind of set the 'minimum scale'. I think I'll try scaling the axles up to 9 studs for the crawler version and trial linkage steering. See how that goes :D
  7. I'm glad you guys like it! I have created a Studio file that contains the fully assembled model and its constituent components, as shown in the render. The file is in my bricksafe folder for the model, which also contains 4 custom parts that you might have to stick in your AppData\Local\Stud.io\CustomParts folder. (the other two parts - one is a 3 stud flip flop beam that Cada makes, and the other is a 3 stud female CV which Studio does not have yet) https://bricksafe.com/pages/autobacon/compact-drivensteered-axle-designs/4x4 Thank you for the positivity! Regarding electronics, I don't currently own any powered-up components, but if I get my hands on a 88009 2 Port hub, angular motor, and an L motor I may try to adapt the model to make it 'more Lego'. I'd like to try using the angular motor as a servo with a pushrod steering setup like Paave used, instead of rack and pinion, I think It could end up being more compact. From the pioneer in quality small-scale RC Lego, thank you :D The tires are 56mm, yes, and also a lot narrower to better suit the scale. Thanks, 1/24 scale crawlers were my main inspiration, I wonder with a lightweight body how close Lego could get to real RC in 1/24, especially when using RC tires. I'm glad you love it :D Thank you. To answer your comments; The shortened arm means the end of the liftarm lines up with the chassis flip-flop beam hole, and you are right, it couldn't be any longer because the steering motor is directly in front of it. Yes, the tires are 56mm, and at the current ride height, they don't rub anywhere in the steering/suspension travel range. This is due to the relatively narrow width compared to 56mm tractor tires, as well as the wheel arch pieces themselves being very thin at the bottom. I think this tire size is the limit of what this fender allows. In terms of suspension, I did play around with weights. Soft springs couldn't really support the body and would allow for too much chassis roll under load, they did give the most flex because once one side of the axle hits the frame, the limit is now how much the opposite spring can stretch. Hard springs didn't really give much flex for crawling. In the end, I got some old medium-weight springs from bricklink, and they seem to be a good middle ground. I think what you are describing in the video is caused by the rearward weight distribution due to the battery position, meaning the model has a bias towards rear suspension flex, and sometimes the front has more to give, it's especially noticeable when the rear axle is loaded. But I do agree with what you are saying. Also something to consider is how small the model is compared to those muddy obstacles, which are nowhere near proportional hehe :D I think before I walk away from this build I might try an alternate build to optimize it for crawling; a super lightweight body, lower the shock towers by a stud for longer travel, and use soft springs for the best flex. Perhaps a simple cabover-style trial truck or a Willy's Jeep. Below you can see the 2L thin liftarm, which acts to counter the downward force when driving forward. Without it, the input shaft mount rolls downwards along the axis drawn with the thick red line. This doesn't cause the gear to slip but the flex means the front and rear axles go out of sync when the front wheels get stopped by an obstacle, as if the front drive axle was connected by a spring to the transfer case. Thanks! I too was pleasantly surprised by the performance with only a single motor! For spring mounting, the spring strength didn't matter too much, I just used my nails to pull down the densely coiled end over the ball joint. It is helpful to put the ball joint in a long liftarm to help hold onto it. Thank you! Regarding the liftarm, there isn't much to show really, I just used a blade to shorten it by a stud and then carefully cut the rough edges away. You can see it in the close-up of the rolling chassis in the video :D
  8. Indeed, one L motor has enough power to move 650g model easily, even with only one down-gearing of 12/20t in the axles, and the tyres have really good deformation with this weight. The fenders come in black on the new Camero, and lime green on some other themed set. This was a bit of a test platform for an improved axle and suspension originating from my wip kraz, I hope to post soon the results!
  9. I have just received the Falken Wildpeak M/T 1.0" tyres I ordered from RC4WD. Posting them here if anyone is interested in how they compare to stock Lego tyres. They measure 56mm x 19mm and fit perfectly on the 30x14mm rims. They are super soft, so with a slightly heavier model they deform a lot which is great for grip. They have transformed the performance of the small RC 4x4 I am working on, and they also suit the scale better than the tractor tyres due to the narrower width.
  10. The last video is perfect, I was looking for some info on the smaller rc4wd tyres the other day! I've ordered the Falken Wildpeak M/T 1.0", 56mm tyre for a 7 stud wide axle 4x4 I'm working on. It has a brick-built body so it should be heavy enough (it's basically finished and about 650g) to take advantage of the grippier tyres as you mentioned in the video. I'll post the results when they arrive in a week or so.
  11. Hi, I noticed on the Mouldking mobile crane 17013 that one of the advertised features is the use of a custom-style CV joint. It looks to me that the male end is the same size as the old Lego CV joint but is slotted and therefore stronger like the new Lego version. Does anyone have any experience with them and if so know where to find them individually?
  12. Would it help to have a spring in the opposite direction of the small cylinder?
  13. I like this a lot. A very challenging scale. Good job.
  14. I have since replaced the CV joints and it has been a massive improvement. Now the weakest component is the front diff. But you are correct, most pressure goes to the rear axles, so it is rarely an issue. So far I have glued zero parts, however, if the additional weight of the cabin causes an issue I may glue some of the front axle parts, I have not decided yet :D Regarding Mouldking battery, it is simply a physical controller with proportional speed control, and it allows for fairly precise movements, I agree it is a little fast for steering particularly when driving, but it is definitely usable and quite easy to set straight, and I think the amount of space saved is worth it. (in the video I was mainly going full left to right due to the small desk space hehehe)
  15. Hi there. So I was inspired by @keymaker and their awesome krAZ 255b build to create my own krAZ 255 truck at a similar scale (56x26 Wrangler tires), first a bit of back story. I've been tinkering with compact driven, steered, and suspended axles for quite a while, with the initial intention of making an RC chassis for the 42122 Wrangler or 10290 Creator 50s Pickup Truck. Anyway, the result was a pair of 11 Stud wide axles, but it took me so long that by the time I created a chassis, I had moved countries and hardly have any Lego with me. Therefore this new project will be for the most part CAD only (apart from some component testing) until I can get some more parts. Goals: I wanted the scale to be as accurate as possible using the 56x26 tires, which means an axle narrower than my current design is required, preferably 9 studs. All 3 axles should be fully driven and suspended. The body and cargo bed should be brick built if it's not too heavy, and the body/bed should sit as low as possible on the frame rails so as to not look like it has a suspension lift kit. The axles and chassis should be constructed favoring simplicity and low part count. The drivetrain should somewhat resemble the real truck, i.e. offset drive, dual rear drive lines, where the 3rd axle's drive line passes over the 2nd axle. I'll also point out that I don't mind modifying parts slightly if I think it is worth it, especially at such a small scale. Anyway, as keymaker did, I'd like to start with the front axle because it has the most constraints. After some experimenting, it became apparent of a few restrictions due to the scale. Springs are too big, rubber connectors should be used as springs and can give a maximum of one stud travel, however, these are very soft. The steering angle will be limited due to the steering rack contacting other parts. If the steering rack was filed down a little it could increase the angle but may end up causing the wheel to contact the frame anyway... A 20-tooth bevel gear is too big and too much effort to integrate, so no gearing down in the axle. Hopefully, with the light rubber springs, this doesn't lead to too much axle torque roll under load or CV joints breaking. Wheel flex could be an issue but again hopefully the overall weight is not too high and the amount of flex won't be too tragic. I'm not too worried about these, however, as I think it's just what happens when you shrink things, compromises have to be made. I also tried shortening the axle of the female CV end for the drive shaft to 1 stud, just because it looked better, might be a bit wobbly, who knows. Positives: Chassis rails are only one stud above the top of the tire, which I think is close enough to the blueprint There is nothing protruding above the rails that could interfere with the cab or motor mounts The axle is firmly held in place and lateral movement should be minimal. That is all for today. I have already almost finalized a rear pair of axles, however, I didn't want to make this post too long. Thanks for reading :D Thanks again to keymaker for the inspiration.
  16. Hmm, this is an interesting point, perhaps I could swap the CV to each axle for the new CV, and shorten the female end from 3 to 2 studs, I like this idea. Regarding weight, I think it should be not that close to your original model. Currently, the chassis with motors and battery is 475g, and stud.io measures the fenders/cabin as 170g. Say we account for up to 100g of accessories such as storage boxes and cabin bench seat, I think the total weight should be around 750g.
  17. I decided to trade some solidity for the improved reliability of CV joints. Since the beginning, I was not happy with putting full torque from the motor on CV, so any gear reduction after CV is beneficial, especially as more weight is being added with the cabin. Using 20T also means the female CV end can remain 2 studs long which should address the concerns of ZeroBrick's comment above. Thanks, yes, as a small model with few functions, replicating the original driveshaft layout was an important goal :D The upper arms are 5L arms that have been shortened by one stud with a Dremel. The lowers are made using 6L arms shortened and joined using a 2L axle connector :D
  18. Hi! Whilst back at home for the holidays, I have finally been able to build the chassis for real! I'm happy to say that with initial testing, it works really well. I can't wait for some proper off-road tests! Below are some testing notes. Good: One Mouldking L motor can easily power the chassis, and the very long wheelbase allows for some very steep hill climbs. The gearing allows for a good top speed, and analog control also allows for precise slow-speed control. Cada Micromotor is strong enough for steering without any gearing and using the analog controller, the steering is adequately precise. The suspension performs very well, with very good articulation on the front axle, no binding of tires at full lock and full compression, neither against the chassis rails nor 9L links. The front suspension can be fully compressed without breaking. I used two of these to attach the upper suspension mounts to the 7L beam - they seem to have a much stronger connection than normal friction pins. I also changed the design ever so slightly featuring a 3L flipflop beam for extra rigidity. 4 rubber pieces for the rear suspension actually prove to be very sturdy, and the truck should be able to support a decent weight over the rear axles. The steering angle is much better than expected. I thought not having suspension extension limiters would cause issues but actually, it just improves articulation in a pendular sort of way, and the drive shafts into each axle act as a sort of bump stop, so they don't droop very far when lifting the model from the ground. Less good: I forgot how weak CV joints are, I think I will try small zip-ties wrapped around the female ends to stop them from flexing apart under load. It's not a big issue but with the extra weight of a cabin, it may become one. The cabin may be too heavy and cause the front wheels to flex apart too much. Further testing is required. Rear tires occasionally bind on the lower 4L suspension links, but it doesn't seem to happen when driving, only when manually manipulating the axles. The front diff is not the strongest, It holds, but it will slip under some conditions. It's not ideal but I'll have to see how it fares with the additional weight of the cabin. Apologies for the questionable quality of the photos and video! Not sure when I will be able to start on the cabin. I think first I will try to sort the front fenders.
  19. Actually, I sanded down the edges of this piece very slightly in order for it to not rub on the standard rims :D
  20. @Fluwoeb Hi! Is this regarding the 4L suspension link? To be honest, I'm already using some non-Lego parts so I'm quite happy fabricating some 4L links out of regular 6L links :D Small update: I have just received a delivery of mixed-length flip-flop beams from Ali-express as suggested by @gyenesvi, as well as a Cada micromotor. I can confirm that such a motor can drive a steering mechanism ungeared, as long as it is paired with an analog controller such as the mouldking 6.0 battery system. With a regular IR remote for example, it would be far too fast. It does seem though it would be beneficial to add an inline friction clutch. I have also managed to redesign the axles a little bit to integrate 12t/20t gear down in the 'diffs' using Zerobricks' advice. It looks like I should be able to do some real-life mockups of the drivetrain in January.
  21. It's actually just a 2739a suspension link, which has been cut in half, shortened, and then glued into the 2L axle connector. The link itself is basically just a cross axle so it fits well.
  22. It was really great following the story of development, I was always left in anticipation of how the solution to each problem is going to look :D The model looks great, it seems very polished and refined, and every part looks like it's meant to be there. Now the journey is over, what is next in the snow runner series? :D Is the chapter of 6x6 complete? :D
  23. You have me worried now! hehe. The calculations say 840g at the moment, and that is without the battery. It is quite a light battery, I don't have it to hand to measure, so let's say the final weight will be 1000g including any part strengthening. Can 1 ungeared motor power that mass offroad? You have given me doubts :D I am using a MouldKing L motor, which according to youtube testers has about 10% more torque than the Lego version. Also, Ingmar Spijkhoven's 1:17.5 scale KrAZ 255b was powered by 2 L motors, weighed very nearly 2kg, and could tow a 500g trailer. Obviously this was with some down gearing, perhaps with my model I could squeeze in a 20t/12t combination into the differentials to help somewhat. When I return home later this month I will mock up a test bed to see how much weight the single motor can shift. Yes, you are correct about the blocked axle, it was only a mock-up to see if there was room :D Space is at a premium here so I don't think I have room for your above recommendation, although I could be wrong. That would be even more difficult if I need to use a 20t gear on the axle though. I also agree the 2L axle into the diffs is worrying. To be honest this whole 'build only in CAD' has included so many assumptions and speculation that I'm nervous the whole drivetrain will crumble in real life!
  24. Since I can't build and test the chassis at the moment, I decided to spend some time mocking up a cab and bed. Bodywork has never been my forte, and I've never tried using bricks, so this is a first for me. This is just a mock-up to see how the scale would work, so the cab and bed are not fixed to the chassis yet, as are the fuel tanks and front fenders/bumper. I'm not quite happy with the fenders yet due to the high placement of the front lights, and I reckon there will be some tire rub at full lock. So next I will be experimenting with fender designs to rectify these issues unless I have to compromise. Another compromise was the middle windscreen pillar, which I couldn't get to look right on this model, so I went without it. The single large motor for drive has been placed under the hood, which is long enough for it to be completely contained. This leaves some room for a bench seat that sits directly above the drive shaft out of the motor. Three 16t gears move the output down 6 studs, the middle gear of which is a red clutch gear to allow the steering axle to pass through. I chose to use a cada micro motor for the steering, which based on the rpm specs, I should be able to use un-geared which means it takes up hardly any room and can be mounted inline, in between the frame rails. I did consider L motors mounted in place of fuel tanks but it doesn't really keep with the style, plus it might be overkill in terms of torque, and with the un-geared drivetrain, I'm quite nervous about ripping cv and u-joints. Lastly, I couldn't find a suitable place to mount the battery. I will be using a MouldKing Batterybox because the physical controller it comes with has proportional control which I really like, but it is a little larger than a buwizz. I may have to put it into the bed, either right at the front or dress it up as cargo. Having never designed bodywork before, I'm quite happy with how it's shaping up, but I am aware that there will be a point where I need to build it outside of the computer so I can figure out how to build it in a strong way, and perhaps fix some parts that don't work in real life. I think I am getting close to this point but I still need to buy some parts or a set to salvage from! Also, I appreciate the feedback and tips so far, and any ideas for the cab will be well received :D