896gerard

Eurobricks Vassals
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About 896gerard

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    Technic

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    Male
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    Lego Technic, modelling

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    The Netherlands

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  1. You're right. A motor is placed inside the cilinder and also in the same tube, not placed in a box behind it. This gives a smooth finish and a Lego look which is not always achieved..
  2. I have done a lot of tests on the above outtriggers with linear actuators and the internal clutches kept engaging. Then I tried pneumatics and the air escaped from the hose fittings, while at the same time my tiny onboard compressor couldn't create enough pressure. The only solution: an entirely new linear actuator, fully developed in house, made to be fully compatible with Lego Technic electronics. This was a complete new experience for me and I learnt a lot in the process. The cilinder gets SLS printed and has full metal mechanics inside, much higher specced than the usual Lego Technic linear actuator. I'm excited about this new cilinder. Soon, the large actuators from the Lego 42100 Liebherr Excavator will be available. Cannot wait to setup a comparative test!
  3. Once in a while, every Technic builder wants to build a Lego boat. I was no exception, but there's a lots of boats being built: how to make an original boat then? I decided to not design a good-looking boat, but to make it a tool for filming. This choice asks for a boat that can be quickly placed into its filming position, which means it should be fast and agile. It should also have enough remote control range to film on big water areas. The 1980's Power Functions remote is thus completely out of the question: responds very slow and outside, there's 2 metres of range. We all must thank S-brick for existing. S-brick (or alternatives) makes this boat possible: without sufficient range, there cannot be a camera boat. Many boats have a keel and a rotating propeller at the back. A submerged plane behind the propeller acts as a rudder. Sadly, a rudder becomes less efffective at lower boat speeds and the boat reacts slowly to it: turning the rudder does not mean turning the boat, it first needs speed (and thus space!) to turn. In Dutch ditches (where I wanted to test the boat), there is not a lot of space available for maneuvering. Having a a slow-responding boat with a rudder there means the boat being into the reed all the time. I therefore eliminated the rudder and mounted the propeller on a hinge. Any hinging of the propeller system at any propeller speed the boat causes immediate turning, which is a nice direct response on the steering input. Good theory, but when a single rotating propeller is mounted on the rear, the boat will rotate along its Z-axis. I'm not sure why this happens. It may happen due to the gyroscopic effect of the propeller or due to the Lego propellers not being made for water propulsion, but anyway I had to deal with it. A second propeller placed next to the first propeller that rotates in the opposite direction seems to to the trick. However, when you mount this system on a single hinge, the (larger) system swings out quite far and easiliy hits reed in the typical tight Dutch waters I tested it in. Also, in windy waters, having a single propeller at the rear means the steering is countersteering all the time just to sail straight on! To deal with the problem, I mounted 1 propeller at the front of the boat and one steered propeller at the rear. This means the boat always tracks straight (even when the wind comes in from any side) and that the propellers can be mounted close to the boat, reducing its draft. The boat is made from 2 boat hulls to create a stable camera platform. This concept worked, it gave a lot of control. I decided to use a race buggy motor as it provides a lot of RPM at low torque, excactly what a boat needs. As no additional parts (for looking nice etc) were added, the boat was light, controllable, fast and really fun to use. The steering is a quite unusual setup (for me). It contains a rack with a 24t gear, a PF Servo motor and a ball link system. This setup had the power and speed that was needed for the steering to be quick. The video The GoPro is mounted upside down under the boat. The high speed axle to the front propeller is also visible. For water level footage, the GoPro is mounted starboard-side of the boat. As the boat only weighs 831 grams, this effects the balance a bit.. Sometimes, I used a rearward-facing camera, mounted in a Lego frame and adjustable by a large linear actuator. The same camera, facing to the front. Due to the size of the boat, there are weight restrictions. The boat wouldn't sink with a mounted DSLR camera, but it would not be stable enough when the wind increases. The Sbrick and PF battery box are mounted on the left side to keep a low center of gravity and to restore the balance (the servo is not in the middle). The boat packs some power, which is visible from the wake in the water. Thanks to S-brick the boat never went out of range so it was also a really nice toy. It might have been faster with BuWizz though, but that question might be answered later. I think this boat really makes a case for the race buggy motor. It has good RPM and power for its size and in the water it never runs out of torque (a problem that can occur on land.. ). Hopefully someday somehow it will be made compatible to Powered Up, otherwise this hero will disappear in the shady realms of the past.
  4. 896gerard

    Ingmar Spijkhoven Passed Away

    My condolences to his family and friends. I remember his incredible trucks and videos. I even bought parts from him: BrickLink Order #5541672 - ... Buys LEGO(R) From Ingmar Spijkhoven 896gerard buys LEGO from 2 LEtGO Or Not 2 LEtGO. Sadly, he had to let go in the end..
  5. I understand. You are right. I was assuming the general idea of 'making an active controlled differential'. The implementation of this idea is different for our models. I was not trying to take the price. I think you have made a brilliant and good-looking model around an original technical principle. That's a good thing.
  6. 896gerard

    42100 Liebherr R9800 Excavator

    I find the fact that all motors have an encoder now very interesting. No more need for servo's !!! So no expensive steering servo, but just a regular motor, this makes them cheaper too. On the other hand, it might not stimulate designer creativity. With 'the old motors', it was always an issue to gear it down or to create a repeating mechanism when a linear movement was needed. Now you can simply program the movement and do the job with very little oldschool mechanics. That opens the road for big clumsy motor-infested MOCs without any space for mechanics (the motors are not getting any smaller). Secondly, I think TLG should think of a remote control with physical levers. A Lego Technic race car with high speed is uncontrollable from a touchscreen because there's no feedback from any knob. Looking on a screen where the slider is while also tracking a very fast object doesn't work.
  7. Regarding this debate, I have another question. (Still for the ultimate model I was talking about) I need a crane outtrigger with an extension of 100 millimetres, two studs wide and strong enough for a 2 kg model. The biggest concern to build this with Lego is that there are no gear racks long enough and small enough to fit within a two studs wide outtrigger. Lego Technic has seen this problem and come up with a part, but the extension is too small for my application. Also, the 18940 part requires an axle leading to the top of it for a powered extension. A a very visible axle does not help with getting a nice visually appealing scale model. Therefore, I decided to take up the gauntlet and start desiging this part for myself. The tried-and-tested prototype is below. This structure can support 10 kgs of weight (tested) and allows a very smooth extension of >100 mm. A big advantage of designing parts myself is that I can adjust the size anytime I want. And this is the time where I need some opinion on this. Is there a Technic way of doing this? Maybe I didn't think of something. I want to exhaust all options before using a non-Technic part inside a Technic model.
  8. I agree, honesty is very important here. That's why I don't want to sell these parts: I have a purist heart and know myself to only use these pieces when nothing else works and know myself to always communicate the use of custom parts. Other builders might not have the same intentions and use the parts only because it needs a lower skill level. That is not my goal.
  9. That's why I posed it as a debate in the first place. Again, it depends on the goal that needs to be achieved with your MOC. For most MOCs, the goal is 'use only Lego pieces'. But why is (for example) the S-brick/ or alternatives so broadly adopted among Technic builders? Because it is a way better solution than any solution that Lego has come up with. I'm currently building a model for which the goal 'use only Lego pieces' is simply not good enough. The concept of many small pieces to build a working scale model is very strong. Lego pieces have also a very high quality and finish, much better than any 3D printed part. But Lego Technic parts have their limits. And that's why I (a builder who normally finds purity so important) for one single time choose to make a MOC that uses the 'use only Lego pieces'-spirit for 95% of its parts and use much better parts for the remaining 5%. This design philosophy does not disprove, but enforce the Lego Technic platform, as it shows how a very strong concept deserve specific parts that are engineered with much better specifications. It is like using non-Lego wheels for offroaders or a custom machined steel turntable for very heavy cranes. Other builders do that. Do they do that because they are non-purists? No. The rest of their machines is mostly impeccably engineered to use 100% Lego parts. They choose it because it lets their machine shine. And shine is what we so hardly need, because other adults (from 'the real world') don't know a thing about Lego Technic building and about parts purity and the lot. They are driven by amazement only, which is not linked to parts purity at all. There are much more adults who admire engineering over parts purity. I have that experience in my talks to some companies around me that are convinced of the Lego platform and asked for models!
  10. Dear readers, For a new project that started a while back (about a year ago), I was investigating a certain track configuration for a tracked vehicle. It pointed out that I needed a lot of ground clearance from the track wheel, but the track wheel could not be two studs wide: the tracked vehicle is only 15 studs wide and a lots of gears, motors and linkages need to be in between. As you can see, the standard wheel above is two studs wide due to a ring of 1/2 a stud that supports the track. This ring is not always necessary. In fact, the tracks barely even touch this ring under normal driving. A lot of you will recognize the difficulty with this wheel: it protrudes half a stud to both sides. In many designs, the number of horizontal studs is uneven: an M motor, XL motor, frames, differential, everything has an uneven width when measured in studs. This enables a symmetrical design as Lego Technic has no beams with even lengths (only 3, 5, 7, 9 ..). That's why many Technic designs of this day are an uneven number of studs wide. This is in contrary to the olden days, where all Technic components and widths were even. Check for example the old style liftarms, differential, frames, motors and even battery boxes. With this theory lesson over, it is easy to see why this track sprocket introduces a problem: when the wheel is mounted in the uneven Technic system (to get a nice symmetrical design with uneven Technic beams), the wheel size is even! So the wheel can not be connected to a liftarm at the place where the axle connects to the wheel. There needs to be a distance of 1 stud to any supporting liftarm. This is mostly done with a bush or a 3L thick liftarm. This also means that to mount this sprocket very strongly, the minimum width of the structure (when fit in an uneven system) is 5 studs. Then I started thinking: how nice would it be if there would be NO distance to any supporting liftarm? In that case, the sprocket has to be only 1 stud thick and the supporting structure is only 3 studs wide. Also, the support ring has to go. This is an enormous space saver when the maximum width of your vehicle is 15 studs.. I decided to draw the part in Solidworks and print it with my own 3D printer. Out of curiosity, I checked GrabCad to check whether someone got the same idea too. To my amazement, somebody had already tried this part, with the internals to be the 40 teeth gear. This is done with a reason. A standard 3D printer is generally very bad at printing axle holes. If you draw the outline of a standard Lego Technic part (that has a nice axle hole) into your 3D printed part, the part will be connected firmly inside the model(nice) while the axle is inserted into a Technic part, so no troubles with cracking plastic will occur. In short, I printed that part. It didn't work. (See image below). It turned out that every 3D printer is a little different. A tiny offset can cause a diameter difference, which then will cause friction, because the track doesn't fit around. The wheel needs to be perfect to make the solution work. That's why I decided to design my own custom sprocket wheel from scratch. This was my first 'from scratch' attempt. As you can see, the pin and axle holes do not have great quality. A revised 3D design is in the image below. As you can see, there is a large hole in the middle. This hole fits two 4185 pulley wheels (shown right) very tight. This means the vehicle is connected to a nice and round axle hole, while the 3D printed part is also fit very well to the vehicle. The sprocket diameter is not arbitrary as the number of 'lobes' is fixed: there are no half lobes, otherwise the wheel won't work.. That means that for the same tracks, a limited number of wheel diameters exist. As you can see, there is a slight ring in the 1 stud wide sprocket wheel, not all track support is gone. The 3D printed results: I was really happy with the quality of this wheel, the drawbacks from 3D printing don't show up and the wheel is very strong and straight. In the image below, is is visible that the tracks fit very smoothly around without additional friction. It is also visible that the wheel is just as wide as two pulley wheels, so one stud. I was so amazed when the 42095 set was launched. There was my not-published-about part, exactly the same size, in a real Technic model! And now there will be 4 DBG ones in the 42100 Liebherr, which will drop the price. There is one 'slight' drawback though. My 3D printed wheel is only one stud wide, needing only a frame of 3 studs wide to support it. The new 42100 sprocket wheel has the 1/2 stud ring protruding out of it on both sides, taking the drawback of the old wheel onto the new wheel. That's a pity. It could have been so nice. Then comes the question: why would you 3D print parts? That's cheating. And I agree. It is cheating. I never do this in my models. You are allowed to check my YouTube. I even built of a 3D printed way of getting three axles through a Lego Technic turntable but never used the solution as I do like pure models. Then, why am I doing it now? Because currently, I'm using Lego Technic as a strong platform for a scale model that requires 100% of the quality of Lego Technic, but cannot do without adding custom parts. Even the most skilled builder cannot work his way round sprocket wheels that don't exist. That's why I see it as an engineering project, and from that prospect, creating your own parts (when all else fails or doesn't exist!!) does not show lack of skill but broadness of view.. Surprisingly, some other minds thought alike and brought a Lego Technic wheel of the same size on the market. Too bad.. Let's start building and stay thinking!
  11. 896gerard

    Technic 2019 Set Discussion

    Regarding the new 42095 sprocket: I'm working on a tracked model for which I designed the above sprocket from scratch in SolidWorks. I have printed this wheel already with my own 3D printer. As I was not happy with the printed pin and axle holes from the 3D printer, the method of connecting this wheel is to squeeze two pulley wheels inside the middle cilinder, which is a tiny bit too small. This connection can handle a lot of torque, depending on the used print material. With my design, I also tackle the problem of the wheel being two studs wide. My wheel is one stud wide. This enables a lot of earlier impossible design solutions. I'm very surprised to see my little secret back-room 3D project so soon in a real Lego Technic set
  12. 896gerard

    General Part Discussion

    I think the frustration about the non-stacking property will be large to such an extent that third parties like S-brick will come with a solution. The change to non-stackable plugs is a bad idea as they could always be stacked. Lego is about finding out, not about being limited!
  13. 896gerard

    42083 - Bugatti Chiron

    Yes, that's why an RHD version would be special. Mirroring the building instructions in your head is quite difficult but some people like it and do it. I'd love to see the result!
  14. 896gerard

    42083 - Bugatti Chiron

    Now you mention UK guys, anyone building a right-hand drive version of the Chiron? It would be a challenge to mirror systems but your Chiron would properly stand out..