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Everything posted by Lipko
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Technic Hall of Fame Discussion
Lipko replied to Jim's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I was thinking about purity too. I think the Hall of fame should include 100% Lego parts models with no gluing at least. Other than that purity is so shady that it shouldn't be that important. -
Non-Zero King-Pin Angle
Lipko replied to DrJB's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Nicjasno: If that instant centre is moving, it doesn't mean your understanding of the topic is wrong. It's easy to pick a point on the hub that's not moving in the driving direction like crazy, but moves in a more or less straight line that's perpendicular to the vehicle direction (axial to the wheels). Every suspension geometry tricks have their tradeoffs. I bet there's another whatever angle that compensates for that axial movement trapezoid linkages have. Or maybe multilink suspensions are more complex 3D linkages. Anyway Linky And look for section 4.3.6 HERE EDIT: what I tried to say: as far as I know, everything in suspension geometry is just approximation and the designer's goal is to find an optimum of all the imperfect solutions for the specific types of vehicles. It's possible that there is a good-approximate center point in trapezoid linkage that's not moving much, even though it's not the centre mechanical-wise. -
Technic Hall of Fame Discussion
Lipko replied to Jim's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Yeah, let the criteria be that the model is built by Blakbird. Then I can make it into the hall too -
Non-Zero King-Pin Angle
Lipko replied to DrJB's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Nicjasno, what do you mean by kingpin? The inclination, or something else? Or all the geometry parameters? You use "kingpin" as a parameter of the geometry, but it's something (if we use it as a synonym for the pivoting axle) every since automobile has. And I agree and disagree with DrJB. As far as I remember from my mechanics courses, the place of a pole point of a multi-link mechanism (the point around which a specific part is turning, for example the wheel hub) is only momentary. Though the pole point may only move a few millimeters. But sometimes the advanced geometry stuff only means a few millimeters. I disagree, because the pivoting point is definitely not simply the intersection of the links. EDIT: the pole point is called Instant centre of rotation. Oh, wait.... DrJB is right. The virtual center is really just the intersection point of the elongated links (of course if we are talking about a trapezoid linkage) -
Non-Zero King-Pin Angle
Lipko replied to DrJB's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Isn't that the Caster? Also it's a bit disturbing that you only use "kingpin" when you really refer to "Kingpin inclination". King pin (according to wikipedia) is something old cars had. Or am I the only one who didn't know that "kingpin" is the synonym for "kingpin inclination"? -
Small lego RC race car
Lipko replied to Taha99's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
L motor has much more connection points too and can be used as an integral part of the chassis. -
White Technic Panels
Lipko replied to DrJB's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I need some white very small panels for my current project. I guess I'll either have to paint some, or give up on them. -
Measuring Power Loss in Gear Trains
Lipko replied to Hrafn's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I'm not sure that measuring the revolutions is a good way for determining the torque. It depends on the torque vs. revolutions characteristic of the motor. And did you put any real load on the geartrain? Like, driving a car, where there is quite a big radial force on at least one axle? Or did it just run freely? Maybe one could try it with winches too. Check how much weight on the input winch can move a certain weight on the output winch. EDIT: too much influence by the winches.- 20 replies
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- gears
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Measuring Power Loss in Gear Trains
Lipko replied to Hrafn's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
It's hard to come up with actual data, because everything depends on how you build the geartrain. Where, how you bear the axles, how flexible is the frame, etc. In many cases, even the rotation direction can make a huge difference. It's possible to use the same gears in the same sequence (and paying attention for not tightening stuff) and achieve very different power loss. As for big vs. small wheels: Teeth are not straight, so whenever they transmit force, the for will have a radial component (the gears want to push apart each other). Smaller gears mean smaller radius. You know, that the torque is tangential_force x radius. So smaller gear needs greater force to transmit the same torque. Greater tangential force means greater radial force. Greater radial force means greater friction at the nearby bearing hole. Sorry for my early-morning English.- 20 replies
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[TECHNIC] What you learned from Lego
Lipko replied to DrJB's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
On the broader scope: Nowadays, Lego taught me that I really suck at inventing and solving mechanical problems, and I'm much better at design (that art thing). Af for particular mechanisms, it's really hard to tell because I devoured mechanical (especially car mechanics) books since I was 6 or 7, so for example I think I already understood the differential (or at least it was familiar for me). Anyway, Lego had a large part in me being a mechanical engineer now. -
I don't agree with the rear wheel thing. Maybe a wide rear wheel what makes a chopper, but for me,. it's boring as sht. I love these much more old school bicycle like motorbikes that those fat claptrap choppers. This is the best looking Lego bike for me, though I would be curious how strong these connector built frames are. Looks too fragile for me to call it the best ever.
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Connecting Tri-Liftarms
Lipko replied to SNIPE's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Couldn't you get away with a near-perfect scalene triangle and build a totally different but more trivial frame? base length: 19L, height: 16L. Okay, the sides would only be 18,5L long, but is that a huge problem? -
Score Fixing on Rebrickable
Lipko replied to JM1971's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
You got me wrong. I said that the randomly posted MOC section IS very good. Something Cuusoo should also have, because it is pretty much a basic thing every site like Cuusoo should have. (Rebrickrable has it, Brickshelf has it, etc) -
Score Fixing on Rebrickable
Lipko replied to JM1971's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
My last models couldn't see a day on the "hottest MOCs" section. One of them won a freakin contest [/irony] Anyhoo, Cuusoo is much more upsetting, because if a model isn't caught up in the first week, it's pretty much impossible to get any significant support. Luckily, Rebrickable (along with most other sites) has the mindblowingly complex and I guess impossible-to-make "browse random models" feature [/irony] Your MOC is on the front page again. My models suck I guess -
Little Manual Rally Car "Kisauto"
Lipko replied to Lipko's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Uploaded PDF instructions. I will add the model soon to rebrickable. -
Technic in Design Limbo?
Lipko replied to allanp's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Well, new, specialized parts mean builders can push the limits of Technic even further. I, for one, am happy that I don't have to custom build a differential or ball joint links so I can focus on more interesting things (not that I am able to push any limits anywhere). About the "how awesome things were made long ago with limited parts" argument, well, most of those I saw used custom, or even metal parts at the most crucial parts of the model. Or at least some glue here or there that's not visible on photographs. Or were not so awesome compared to today's "standards". Imagine Sheepo's latest cars in with 1980 parts inventory (the reason I don't mention you, Nicjasno because you use custom parts). Fortunately Technic is nowhere near the level some Lego system/town/whatever models and pars became, where there is almost a complete car part with two random studs to make it "Lego". -
How about a separate MoM award, and post on the Frontpage whatever that's Frontpage-worthy? Technic isn't gaining enough interest anyway, why missing interesting models just because Sheepo has a model in the same month, or why posting a lame model, just because it's the best in that month? We just need more active Technic posting on the Frontpage. I haven't seen much Technic there. Technic models need more attention. See Cuusoo, see Facebook for example (I wrote to a shop active on FB once that they never post any Technic models. The answer was "I haven't seen a good Technic model in the last years" What The Flying F*ck) I don't know how big the traffic here on Eurobricks is, but maybe Eurobricks could do something about this attention with some Frontpaging.
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Concept Car Hubless Wheels
Lipko replied to raus's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
That model would be good and interesting enough even with regular wheels.