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Tamas Juhasz
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Everything posted by Tamas Juhasz
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Tamas Juhasz replied to Zerobricks's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingDon't compare a man to a 2 kg little construction. WEIGHT does matter! It's so simple. If you show me a video, where a 2 kg car pulls a ~ 1000 kg real one (with real road tyres, not extreme wheels), I believe. But it's physic. Anyway why we can't see 100% of Zblj's car in the video? -
Tamas Juhasz replied to Zerobricks's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingGreat performance, congrats! I think the car pulling want's to be a joke. The question: was the car in a slope (even on a 0,5 % one) or was pushed by someone? Let's count a bit: if the car is ~ 2 kg, and g is 10, then you have 20 N vertical force from the weight. --> This is the theoretical maximum pulling force. 20 N doesn't moves such a car.
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingLike an amphibious vehicle with the air inside the tires? I bet it would sank. 4,2 kg own weight is too much for 8 PP wheel's lifting force. I'm not an english genius, so if I understand well your question: the step controller gives advantage, you can drive also slowly through risky stages or similar terrain. The truck's dynamism also helps, in this speed and weight that also matters a bit. In low traction stages the spinning of wheels in third step on the controller can help.
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThx guys. I have only 14 PP wheels, for my 16x16 plans I need two more. I had bought a 8466 wheel set from ebay, and I have 4 from 8466 too. Other wheels came separately during the years, the patterned ones are from the power puller. Only the 8 wheels weight 1485 gramms. I never tried, but it's very likely. Yes, I found, the additional stability is a big advantage of the heavy PP wheels. Without those the center of gravity would be much higher because of the RC units close to the "top".
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Hello! This moc was made a while ago (last year), but I realized, there is no topic about it yet. I wanted to make a heavy and fast trial truck from Zis e134. Original model: My version: folder: http://www.brickshel...ry.cgi?f=496827 Basically, it was built for truck trial race, so it has a "propulsion motor/weight" ratio, each RC buggy motor carries ~ 1 kg. There are 4 buggy motor built in, each axle has one. Only two gearings (40:8 and after that a 24:8 reduction) are in the drivetrain in each axle, so I hadn't problems with efficiency. Total wieght became 4190 g. I used 1957 parts to build it. It's my longest and heaviest trial truck yet, total length is 610 mm (width: 283 mm). The 4 motors give enough power to reach 1,7 km/h top speed (flat surface), I used two RC units to power them. I think the most important part in these 8x8 trucks is the suspension. I tried to make a long travel one, which allows the wheels to make contact with the ground in extreme terrain also. The rear axles are built in a unit, which has a linkage (see pictures). This unit can bend also, but not sideways. The two front axles can bend sideways, and lenghtwise also. So without springs, the suspension does it's job: The second and third axle are connected together with these bars. They seems weak to here, but I can say, there weren't problems with those during the tests and races. They don't hold the axles, only make positioning, but of course, some force can be appear: Bottom: I made some details, like net in the driver's door, flags, grilles to the front: This truck was able to drive in heavy snow. Pictures: http://www.brickshel...y.cgi?i=5398922 http://www.brickshel...y.cgi?i=5398926 http://www.brickshel...y.cgi?i=5398931 http://www.brickshel...y.cgi?i=5398933 http://www.brickshel...y.cgi?i=5398940 http://www.brickshel...y.cgi?i=5398970 http://www.brickshelf.com/cgi-bin/gallery.cgi?i=5399011 http://www.brickshel...y.cgi?i=5398941 VIDEO: SNOW VIDEO: Hope you like it.
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Tamas Juhasz replied to efferman's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingEfferman: Thanks for the answer. But I think "RC4WD roklox" and "RC4WD 1.9" rock crusher XT" has the same material. Maybe there is no softer 1.9 tire than these (X3 soft & sticky compound)?
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Tamas Juhasz replied to efferman's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingNobody knows? I think about softer 1.9" tires than RC4WD 1.9" rock crusher XT.
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Tamas Juhasz replied to efferman's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingWhat do you think, which is the softest 1.9 inch tyre for 8297 rims? I need hard terrain crawler tyres, but as soft, as possible.
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Tamas Juhasz replied to Kumbbl's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThis is the essence. I strongly agree with every words. Anyway there is no best ever. Always can be built a better one, but also important, what is the goal with the outrigger.
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Tamas Juhasz replied to efferman's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingHi! I was thinking about an order of these wheels, but they seems too cheap to me, and the seller doesn't wrote the company which produced the wheels, maybe they are copy/fake of the Ansmann and RC4WD wheels: http://www.ebay.co.uk/itm/160838773023?var=460088207523&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 (original: http://store.rc4wd.com/Rock-Crusher-XT-19-Tires_p_691.html ) Or do you suggest to order the wheels from the USA (RC4WD)? How much would be the cheapest shipping for 4 wheels to EU (Hungary)? Should I pay additional charges in case of $30 value, or only the item+shipping price? Is here anybody who ordered from RC4WD store to Europe?
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Tamas Juhasz replied to Multidomar's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingI made this last year: http://www.brickshel...ry.cgi?f=507850
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Tamas Juhasz replied to Sheepo's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling"Does it change something": in such big cars top speed is a very informative data, it matters a lot how much is the value. The faster car is better, if we see only the performance. If you can go even 2,5 kph with this two motors and two gearing up combination, you have specially overboosted L motors. (I'm an engineer, I see this moc also with "engineer eyes" ) Where did you write the gearing up between the gearbox and drive motors? The "top speed and similars" are important because of the challenge to build a vehicle which is complex/big AND fast. This is the real challange IMHO with Lego motors. Speed is one of the biggest problems I see in this forum, with bigger, heavier cars (more than 2 kg) it's very hard to reach significant speed. Of course, in a slope down you can reach easily even 5 kph with a big car, so in a special viewpoint the top speed you wrote can be true. But again: I like this car. Others?
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Tamas Juhasz replied to Sheepo's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingI forgot something: you have increased rotation in the 5th gear (1:1,666), even with that and with maximum rpm of the L motor (390, it goes down much during the drive) and maximum (100%) efficiency you can reach 2,39 km/h with that rear wheel. If I see well the 28:20 and 24:8 reductions after the gearbox. With numbers: (390/60)/(1,4*3) = 1,54 rotation per second --> 0,0816*3,141592 = 0,256 meter per wheel rotation --> 1,54*0,256 (*3,6) = 2,39 km/h So the 3 km/h is phisically impossible. (Or you have extra gearing up somewhere) But as I wrote, it's a great car, I'm just curious about your speed measurement.
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Tamas Juhasz replied to Sheepo's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingFirst of all: Great car, very nice funcionality and design! Sheepo: I wrote about the top speed also by the Defender, there was no response, and I had to ask the same about this car: How do you measure the top speed? 3 kph with this car? It's VERY hard to belive. It has a gearbox with many gears, differential, 3 kg weight (!) and only two L motors. L motor has 1,8 W power, in this car 3,6 --> without any gearing (efficiency matters) maybe It's possible to reach the 3kph. But with such drivetrain... Once I made a 2,2 kg semi-trailer: with the most efficient drivetrain (simpliest gearbox possible, overall 4 gear combination) and with two XLmotors, was able to go 1,1 km/h. Of course with good batteries. (Ok, with V2 receivers maybe 1,4.) I hope you understand why I don't belive this top speed. If your car were 1 kg, then ok, but it's 3. That's why I asked about the measurement method, because your top speed isn't fit to reality. Was there a slope (gravitational help) during the measurement?
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Tamas Juhasz replied to Brick_Laboratory's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingBrilliant idea! Is there a special placing of the glasses to get this enlargement? Do you have building instructions? (or are you planning to make it?)
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThx! Thanks for sharing, it's new to me. From this case we can see one big truth: simple (basic) ideas can appear in other builders too. (We can only see, who published it first) Of course, Zblj is (also) "inventor" of this worm gear mechanism. I'm sure that will be others too. Ok, I write to YOU again: why should you use a bush+gear instead of a single tight 8t gear? As I wrote, with a good 8t gear there is just no popping off. The solution is so simple. Or you have only loose 8t gears?
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingI use it as can be seen in the pictures, and works well, I think it's better if you use a tighter 8t gear than glue. You are right, but belive me, it's unnecessary. You even don't need a very tight gear, an average is enough. Even I didn't know about this "problem" until now, because it never happened to me.
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThanks all. It's reliable, believe me. It depends on the gear: of course, a tight gear works well, a loose one which can slide easily on the axle isn't good. That's all. I built mine with a medium tight 8t gear, and there wasn't any problem during the lot of operation (about 100 times switched the lever). Sometimes it's important, to choose the "better" one from the same part, even the same have different geometry (micrometers), resistance (pneu valves), etc. You have to choose the ones which are best for the construction.
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Hi! Some days ago, I created this autovalve: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=534632 My goal was to keep it small and reliable. If there is something, which can be build in a lot of variation, that's the autovalve. (If you don't know what it is: autovalves are made to remote control the pneumatic valves, the motor switches also the valve during making pressure with the compressor. The valve's position depends on the motor's turning direction) I needed as small autovalve as possible, and I also wanted to make something own. This one never can get stuck, I think this is the most important. Some other ones, I tried out, sometimes get stuck when I wanted to start them again or when they reached a special position. For working properly, it requires strong black pins ( http://www.brickshelf.com/cgi-bin/gallery.cgi?i=5955002 ; or the very old ones in 8842) if the valve is new, and hard to move it's lever. The pictures tell the working principle, I tried to make it very simple. The worm gear moves the 8t gear which is built together with the valve lever. The worm gear "ends", when the lever reaches one of the two final positions. The other 8t gear with the blue pin is for going backwards. Sometimes it doesn't needed, but without that it wouldn't be 100% reliable. There is a difference also between the blue pins, so if you choose well, it requires absolutely minimum power to turn. A little video:
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Tamas Juhasz replied to Jim's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingSounds good both. LDD or other CAD models are also allowed? Anyway the secret competition is a very good idea. Other way could be that it will be public with pictures and voting, but the entries (pictures) would be anonym. That could make good chances.
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingIt's built in pretty deep in a moc, so maybe I should make another actuator for the video, when I have time. The problem is, I don't have 10 kg weight from small objects. Yes, I have seen that also. From pneumatic you need such a lot to raise heavy booms. Panels: for 3x11 panel can make a rounded profile, but it would be 4 stud tall or wide just the inner part. It would be much bigger than mine, but this only means that would be good for very very big machines. I need actuator in this scale (outer shell: 4x3 or 3x3, max. 4x4 stud).
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingIt's good to hear you like it. That could work, but this actuator is for heavy booms, they can easily pull back the inner part. If the moveable structure/part isn't heavy, then we can use the regular methods to move it. I'm just trying to say that I see no application where big force is needed in both ways.(ok, rubber band can't create much force, but then it's unneccessary, gravity does the same) Maybe I will make a video later, but wouldn't be so interesting, you would see a raising boom or something like that. Thanks. 3x11 panels? Do you think about the new (42009 have them) ones? How could I keep the ~ 4x3 profile size with those? I think they would be much weaker also. There isn't stronger connection than plate-liftarm put together. Only advantage would be a bit more rounded shape, but black "pins ends" and holes could be seen.
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Hello! I made some experiments nowadays, also this string operated actuator for heavy equipments: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=534220 (this last picture is from another model, just shows the working method) The working pricniple is very simple and effective: the winch in the end of the housing (yellow) pulls out the liftarm construction (gray) with string(s). This isn't realistic, but think about TLC's actuators, they aren't also. I made it for heavy equipment, like crane booms, excavator arms, etc. For raising a big boom, pneumatic has no chance, Lego actuators also. There are two ways after that: custom actuators/custom pieces, or built actuators. I think string is "legal", it can be made also with Lego strings (but would be expensive), so it's 100% legal. The extension is 15 stud (can be a few studs more, but that would be in the "limit zone"). With longer construction it can be even 30 studs (more would cause deflection). I wanted to make it as small as possible, it's 3,8 studs wide, 3 tall. The length can be chosen freely (as long as you want - you just need longer liftarms, or more). The final version in my projects will have bley thin liftarms instead of these black ones, so it will be looking like a real cylinder from a distance. There is 4 paralell strings in this actuator, and at the beginning of the housing there is a little pulley to decrease friction ( http://www.brickshelf.com/gallery/mbmc137/Ideas-Technologies/Extrem-Cylinder/003.jpg ). Strings are very good for smart techniques, this actautor doesn't requires much additional space for motorizing, just make a gearing with a motor after the winch's axle. Of course, you can change the strength of the actuator with stronger/weaker strings. The one in the pictures can create about 100 N of pushing force. This is a bit more than a 10 kg vertical lifting. The backward movement is done by the gravity, but it's not impossible to modify it to pull back the inner part (you can add another string, like 8421's boom extension works). What do you think?
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Tamas Juhasz replied to aol000xw's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingDon't use individual m motors in each axle. If they aren't connected mechanically, it can be easily that after a while the two axles will have different basic state in steering angles. For example the front wheels are paralell with the body, but the rear has 10° right. Use two servos in each axles, that works.
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Tamas Juhasz replied to Tamas Juhasz's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThere is 8 motor in total: 1 XL motor for propulsion and 7 M motor for other functions. The wheels can't go up/down theoretically, because it has no suspension. In the video the obstacles cause a little deformation on the axle's parts, and the axles which aren't above the obstacle are raised from the ground. Axles: http://www.brickshel...y.cgi?i=5936235 http://www.brickshel...y.cgi?i=5936236 http://www.brickshel...y.cgi?i=5936237 http://www.brickshel...y.cgi?i=5936238 - it can be, that you find a similar one, in this size there is only a few possibiliteis to create a non-suspended driven and steered axle.
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