DrJB

I have pondered why TLG rarely includes a motorized platform rotation in their official models, especially when the large turntable is included. To my knowledge, only two large models have such function: the 8043 excavator and the 8258 Crane Truck (there might be others) ... Now, when it omes to the iconic cranes, 42009, 8421 and. Others, none of those have a motorized platform turntable. Why is that? At first I thought it was just to limit the complexity but then it occurred to me that, with such large boom, maybe any gear meshing with the turntable will easily break if one pushes the wrong way ... Any other thoughts or explanations why such feature has been consistently missing?

I think we're going to get them too, but I believe they still have many of the old sets that they have not sold yet, and do not want the new sets to compete with the old, or vice versa. In the US, lego prices tend to fluctuate very little ...

I asked the store manager of one of the Chicago stores, and apparently some new sets are to be released by mid-march ... Just keeping my fingers crossed.

True ... but Volvo does not make their own tires ... typically the tires are fitted based on what the buyer wants. If it's for clean surface work, then the vehicle is fitted with radial tires. If however the vehicle is destined for rough terrain, it is fitted with bias-ply tires (with large lugs, similar to tractors). Last, if the vehicle is to work in an area where there is a lot of sharp/metal scrap, then the vehicle is fitter with solid rubber tires (those are most expensive). This is not true for wheel loaders only, but also applies to graders and some other construction machinery.

Well ... how do you know (for sure) it's Lego's mistake? Do you have tracking on such packages? My experience with Lego is only positive ... I'd check elsewhere just to make sure.

Those are not racing wheels/tires ... need to keep in mind what wheel loaders are used for. In contrast to back-hoes or tractors, a large number of wheel loaders are used to move dirt. Thus, all the tires need is high load capacity and high flotation. Typically, the hevily ribbed tires (on tractors) are of little use on wheel loaders as you do not need such a large tractive effort. Again, very application specific ... though I am not aware of 'lugged' tires big enough for such wheel-loader. The 9398 are a bit small, the power-puller too big (if you can find them)

Thank you, was not aware of that. Mods: Please move/merge two threads.

I got and built the 42009 and am a a bit surprized that there are more extra parts than usual ... 3× axles, 2× 12t gears, + the usual small pins and bushings. Anyone has an exact list of left-over parts once the main model is built?

I did not catch this the first time ... ouch ... wishing you all the very best.

I tried that today at TRU and the lady/salesperson was willing to honor the price-match ... until a manager came and objected ... 'We do not price-match against low quantities' ... I was tempted to say "duh, show me the written policy" ... but felt it was a wasted effort ... I'll live.

Well, the lid could still fit, but not lock in tightly ... could have made it hold with a piece of tape. My issue was not the store policy per say ... it was this overzealous/ugly/obnoxious kid wanting to be holier than the pope .. I did not pay attention to what he did with the cup because I often visit that store and never had any issues ... It was just that single event that left a sour taste in my mouth. What he took out was maybe 50 cents worth ... but it did upset me way more than that. I'm way over it and never lost any sleep though.

Not sure it got anything to do with Lego/LDD. It is however how the graphics from LDD are handled by your video card. Have you upgraded/changed your video card recently? Within LDD, you can change the render mode to display smooth surfaces or with distinct outlines/edges ... Try those and see what happens. I have a 3rd monitor connected to my laptop, via a HiS USB to DVI cable, and I see issues like that only on that extended screen. The picture/copy/paste runs fine if I used the other 2 terminals ... Hope this helps

This is the same as chinese companies copying lego designs and selling them as their own ... just on a much smaller scale. You may dislike it (and we all do), but not sure anything can be done about it.

Any update on the hexa-swashplate? Also, can your penta/hexa turntable designs be uploaded to shapeways?

bbqqq did a turntable with 5 blades ... for a helicopter rotor/swashplate ... can that be updated/uploaded to shapeways? Thread is somewhere within the Technic subforum, but can't find it. Edit: Found the thread http://www.eurobrick...pic=90047&st=25

I'd say let's hope the auction price stays VERY low ... and that'll teach him a lesson Or better yet ... ASK a question, typically such questions remain there for all to see ... Make sure you mention he copied ur designs, in the body of the question.

Very nice, reminds me of the various dodecahedrons and other shapes you see on Mathematica ... I think Matlab calls them 'Bucky Balls'

Could it be this: You have to make sure you use the correct notation for decimal point. In Europe, the coma (virgule) is used. In the US, the dot/point is used. I had such issue on something as basic as Excel, trying to open files I obtained from German colleagues ...

Aswin: Sounds like this definitely will be a fun robot to build/program ... I just need to find the time to sit down and do this. In your initial post (blog) you mentioned you're using a 3rd party OS for the Brick (LeJos?) ... Simple Question: Is this a must? Can't the original EV3 software handle the programming?

That's exactly what I was thinking of ... but with 40 dB should look 'better'

Here's the verdict 1. EV3: is the latest, thus more compatible with existing computers, tablets, ... etc 2. NXT: has a large user base, though if you're considering NXT, go for the EV3, you get one more motor port and SD card storage (and other improvements) 3. RCX: Compatible with studded Technic, old motors/sensors .. can get cheap sets off eBay for $50 ... but will NOT run on any recent computer, and support is fading. Can't run on Windows 7, programming language rather limited. All said and done, and if you're starting from scratch, get the EV3 ... then your next question should be: Retail or EDU version? Well, there are multiple posts about this already on EB, it all depends on your existing parts collection. The 'basic' software is free for both and does quite a bit already.

Not sure what delta angles are ... care to elaborate? The kinematics is rather easy: the rpm of each tire is the same (scaled by the radius) as that tire's tangential speed, or alternatively the speed (along the tire circumference) of the tire's attachment point. Thus, one can write the motion of each tire's center point in terms of the robot's 3 DOF (2 translations and a rotation). This is the forward kinematics problem. If one wants to know the robot's motion in terms of what each of the tires is doing, then it's an 'inverse' kinematics problem and the equations can be 'reversed'. The next level would be to make the robot 'interact' with its surroundings, by adding some sensors. That is where some combination of forward/inverse kinematics might come in handy.

Wanna try it but ... I only have 7 of those wheels, I wonder if a smaller version is possible with the the 40 DB gears ... no need for it to be motorized though.

Thank you. Rather neat that you did all the 'math' by add/sub mechanisms ... really nice. Do you have a link to more info? My initial thinking was (is?) to use a joystick controller a bit similar to the one in the video below (Time Mark 3:16)

Stumbled upon this ... It does not do any fancy motion, but I'm sure the construction/mechanics would be nteresting