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fmmjqtft
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1h 2012 models
fmmjqtft replied to JunkstyleGio's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Here is an updated version and a sketch of the new turntable. ldr file 120 frame render A better render (of the previous version): New turntable: -
1h 2012 models
fmmjqtft replied to JunkstyleGio's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Here is my attempt to reverse engineer the 9391 from the first images (before seeing the images that appeared yesterday). I think most of what I've done is correct, but there are still some missing pieces. Also, the boom doesn't seem to be able to go horizontal. The pictures of the b-model also confirm certain pieces which were impossible to see in the other images (for example the 2x3 plate at the back of the excavator is visible on the b-model). I'll post an updated version tomorrow with the ldr file. -
So far my design fails . Today I tried building it into a vehicle similar to 8635, but it only worked when suspended in air. The construction bends too much when the wheels touch the ground. It is difficult to build a working model at such a small scale. Anyone who wants to give it a try can use this diagram: It is a parallelogram where two sides must be rotated in the opposite direction to the other two sides, relative to the vehicle. The blue angles have the same value.
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Here: A similar modification can also be made to my other design (at the top of this page). Here is the ldr: ---------------------------------------- 0 Untitled 0 Name: steering2.ldr 0 Author: MLCad 0 Unofficial Model 0 ROTATION CENTER 0 0 0 1 "Custom" 0 ROTATION CONFIG 0 0 1 7 -40 -30 10 -1 0 0 0 0 -1 0 -1 0 48989.dat 1 7 40 -30 10 -1 0 0 0 0 -1 0 -1 0 48989.dat 1 28 60 -30 -10 -1 0 0 0 0 -1 0 -1 0 6587.dat 1 28 -60 -30 -10 1 0 0 0 0 -1 0 1 0 6587.dat 1 7 -55 -30 -10 0 0 -1 -1 0 0 0 1 0 32123a.dat 1 7 55 -30 -10 0 0 -1 -1 0 0 0 1 0 32123a.dat 1 14 0 -45 -10 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 14 0 -55 -10 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 14 0 -45 30 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 14 0 -55 30 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 14 0 -55 -50 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 14 0 -45 -50 0 0 -1 0 -1 0 -1 0 0 32017.dat 1 0 0 -35 30 -1 0 0 0 1 0 0 0 -1 6632.dat 1 0 0 -25 30 -1 0 0 0 1 0 0 0 -1 6632.dat 1 14 -40 -10 -30 -1 0 0 0 1 0 0 0 -1 32523.dat 1 14 40 -10 -30 -1 0 0 0 1 0 0 0 -1 32523.dat 1 14 0 -90 -30 -1 0 0 0 1 0 0 0 -1 32523.dat 1 8 0 -70 -10 -0.980785 -0.19509 0 0 0 1 -0.19509 0.980785 0 6542.dat 1 7 0 -70 30 -1 0 0 0 0 1 0 1 0 4019.dat 1 7 0 -70 -50 -1 0 0 0 0 1 0 1 0 4019.dat 1 7 0 -50 30 0 0 1 1 0 0 0 1 0 4519.dat 1 0 0 -60 -10 0 0 1 1 0 0 0 1 0 3706.dat 1 0 0 -60 -50 0 0 1 1 0 0 0 1 0 3706.dat 1 7 40 -30 -50 0 0 1 1 0 0 0 1 0 87082.dat 1 7 -40 -30 -50 0 0 1 1 0 0 0 1 0 87082.dat 1 8 0 -30 -50 0 0 -1 0 -1 0 -1 0 0 60483.dat 1 0 -20 -40 -50 0 0 -1 1 0 0 0 -1 0 3673.dat 0 ----------------------------------------
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It probably is possible to make a working model smaller than 5x5LL, but it would have to be taller. Note that this particular construction will not work if built (the blue axle pin will slip), but it can probably be modified to work with an extra 1L of height. To make a smaller version, it may be easier to turn the red and green parts from further away, using two axles, instead of trying to build two gears onto the construction.
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Here is my design. Each pivot axis remains in the exact centre of its wheel, but the wheels move inwards slightly as the vehicle steers. Assumption to be made: 1. The blue friction pin never slips. 2. The position of the blue friction pin is fixed relative to the vehicle, but it can freely rotate about its axis of symmetry. 3. The position of the central '3L Axle with stop' is fixed, but it can freely rotate about its axis of symmetry. The reason for using a friction pin here is that the 16t gear has to be rotated through 11.25 degrees, which is difficult to do with other parts. The wheels are both offset by 0.5L so that the axis of symmetry is central. Top: Bottom: I will upload an ldr file and draw a diagram later. Edit: Here is the ldr file: -------------------------------------------------- 0 Untitled 0 Name: steering1.ldr 0 Author: MLCad 0 Unofficial Model 0 ROTATION CENTER 0 0 0 1 "Custom" 0 ROTATION CONFIG 0 0 1 0 0 -50 30 0 0 1 0 1 0 -1 0 0 32316.dat 1 0 0 -50 -10 0 0 1 0 1 0 -1 0 0 32316.dat 1 0 0 -50 -50 0 0 1 0 1 0 -1 0 0 32316.dat 1 14 -80 -30 -10 0 0 1 0 1 0 -1 0 0 55982.dat 1 14 80 -30 -10 0 0 -1 0 1 0 1 0 0 55982.dat 1 7 -40 -30 10 -1 0 0 0 0 -1 0 -1 0 48989.dat 1 7 40 -30 10 -1 0 0 0 0 -1 0 -1 0 48989.dat 1 7 0 -70 -10 -1 0 0 0 0 -1 0 -1 0 4019.dat 1 7 0 -70 -50 -0.980785 -0.19509 0 0 0 -1 0.19509 -0.980785 0 4019.dat 1 8 0 -30 -10 -1 0 0 0 -1 0 0 0 1 33299.dat 1 28 0 -50 -10 0 -1 0 1 0 0 0 0 1 6587.dat 1 28 60 -30 -10 -1 0 0 0 0 -1 0 -1 0 6587.dat 1 28 -60 -30 -10 1 0 0 0 0 -1 0 1 0 6587.dat 1 1 0 -60 -50 0 -0.980785 -0.19509 -1 0 0 0 0.19509 -0.980785 3749.dat 1 0 40.275 -10 -29.74 -1 0 0 0 1 0 0 0 -1 32523.dat 1 0 -39.725 -10 -29.74 -1 0 0 0 1 0 0 0 -1 32523.dat 1 0 80 -30 -10 0 0 -1 0 1 0 1 0 0 30391.dat 1 0 -80 -30 -10 0 0 -1 0 1 0 1 0 0 30391.dat 1 19 40 -30 -50 0 0 -1 -1 0 0 0 1 0 32556.dat 1 19 -40 -30 -50 0 0 -1 -1 0 0 0 1 0 32556.dat 0 -------------------------------------------------- Please note that this particular design will not work if built, but it should be easy to modify.
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Electromechanical gearbox
fmmjqtft replied to Zerobricks's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
The current would not be a problem. Assuming a stalled current cannot be higher at a lower voltage, the total current is limited to 1/(1/M + 1/XL), where M and XL are the stalled currents of the M and XL motors at voltage V. If V=9v and M=0.85A and XL=1.8A, the maximum current is 0.577A. This assumes a voltage drop of 9v over each motor, which is impossible, so the current will be lower. Anyway, heres another idea. Use two motors in series as a differential. Two identical motors connected in series have very similar properties to one motor driving a differential, but with double the ohmic (that is the minimum/stalled) resistance, so with half the maximum torque. -
The Technic challenges are not really 'challenges' at all; there are no particular goals that a model must achieve in order to win, other than recieving votes. Each entrant just sends in a low resolution picture showing a technic model with no proof that it is theirs, or that it even works. Most of the themes are too vague and cover too many vehicles. Instead the challenge should be to build a specific machine with a limit on the number of pieces. The NXTLOG challenges are better (although still have vague criteria). Each entrant can upload pictures/videos/ldd-models/nxt-g programs, and a good description is probably required in order to win. I think they should make a Technic version of NXTLOG, or just stop the Techinc challenges completely. Yes.