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mocbuild101
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Everything posted by mocbuild101
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I am weighing it with the watch (that is 45gm) attached, if I take that off, it only weighs 625gm - only 5gm more than yours. Yes I know, and I have already made a new car that has a longer wheelbase and a center of gravity that is much lower to the ground. No, I am using 24:12, like this: -
Nice, but I can't help thinking that all that weight will slow it down - 1080gm is very heavy! And you also have the same 2:1 gearing that I used in my 670gm car: - yes, you have 4 motors, but they aren't fully powered.
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After my last car I had a goal to lose weight - and I succeeded! - in fact, I managed to lose a whopping 110gm! I also used the idea @Marxpek suggested - putting the front wheels through half beams to reduce friction. So here it is: - 2:1 gearing, 670gm Here is the results of the tests: And yes, I have increased my top speed to 28.4km/h! But I don't think I got the full speed from this car - because it was so unstable, it kept flipping over halfway down the track - every time I tried it! If I can get all the way down the track, I think I could get above 30km/h! - but I will have to redesign it first...
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I'd say that is probably about right, the motors will never get up to full rpm. Exactly, because when you gear up, any resistance on the output axle will be multiplied on the motor's axle - so gearing up 2:1 will double the resistance, and gearing up 5:1 will be 5x the resistance - which is a lot! But you can stall the electric motor if you gear up too much - in fact, even with a load that allows the motor to turn can still draw so much current (up to 6.4A for just 2 buggy motors) that the RC unit will shut down, stopping the car. (of course it will start up again, which will then cause a hiccup behavior)
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Yes, but even the cars that we have made so far can't be used like a normal RC car. The key is to get the balance of acceleration and speed just right, which would be much easier with a longer track.
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Climber VII
mocbuild101 replied to shuoshuoliuliu's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Nice! It looks great with the red wheels! Are there more photos or a video? -
I agree, the method I'm trying to keep doing is: car not moving -> start motors via RC -> top speed. I can't believe how often this is happening!
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I was thinking of making a separate pullback car with it's own wheels, connected to the main car via a loose axle-in-pin-hole connection. As for launching it, I was hoping to be able to make some kind of mechanism that will release the pullback motor when the main car starts moving.
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Not when I have to walk halfway down the track before I start - to stay in range.
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What I'd really want is the same style of RC we have in Lego at the moment, but with modern components - 2.4ghz remote and receiver, digitally proportional servo, and brushless motors. But it doesn't seem like you will be going that far . Am I right in thinking that you are making something to go between the Lego controller and the brushless motors?
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Interesting, I might try that - but not yet, because I have already made another car to test (which I have very high hopes for!). Yeah, I was thinking the same thing... again!
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Agreed, and I guess that's also why I like MLcad so much!
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Yeah I know, but I thought I'd try them because they are quite soft - so it is kind-of like suspension. I will be using the motorbike wheels from now on. Hmm... Here's another view of how I mounted it - if you are interested:
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Volcano RS Supercar
mocbuild101 replied to Charbel's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Amazing!!! - that's all I can say... -
That's a good idea, pullback motors certainly can go very fast! But don't forget, pullback motors produce a lot of toque - so you will need very grippy wheels.
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Today I thought I'd try a couple of things that hadn't been tried yet: balloon tires and a pullback motor for a boost at the start. So here it is: - 2:1 gearing, 780gm Here is the results of the tests: So as you can see, it didn't work! - only 22.7km/h The pullback motor did give a boost at the start, but the added weight and friction slowed it down - a lot! Well, to quote: "failure is always an option" (I think some of you will know where that's from)
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MLcad isn't clumsy or illegible, (and personally I don't think it's outdated either) and it's also much simpler than LDcad, yes LDcad has some features that are better - better editor and brick-snapping - but that's only if you have a computer that can handle it. And yes, I have used them both. Although I have not used Stud.io yet - I have a bit of a problem with it...
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LDD is the best to start with - easy to use, and it can make instructions automatically (although they are not very good). But if you plan to be making proper PDF instructions, I would definitely start with one of the LDraw programs - which I would recommend MLcad, unless you want brick-snapping (like LDD has) - which in that case you would use LDcad.
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I'm going to be testing 2:1 gearing tomorrow, but with only 2 motors. I don't think that air resistance will slow anything down much. It's BRICKstorming .
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How long do you keep mocs or sets together?
mocbuild101 replied to Aventador2004's topic in General LEGO Discussion
So what do you do for parts, buy them all from bricklink? -
How right you are! - not only did I think of the same steering setup, but I thought of that same way to reduce friction!
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I forgot to mention that, here's a quick video of it: http://bricksafe.com/files/mocbuild101/super-speedcar/Car1-steering video.mpg I have a shelf (about 50x60x40cm) that I covered the inside with white paper, and lit with 2 super bright LED lights, then I put it through GIMP to adjust the brightness/contrast. It might seem a lot of work, but I've got quite good at it - so it only takes a couple of minutes.
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I have decided to make a WIP topic for my tests of my speedcar, which is a car that I hope to get up to 40km/h or more. But I don't want this to turn into a discussion about wheels, I just want it to be a place to show my progress. This is where I will be doing most of my tests: - it's about 80m of very smooth car park + 15m of footpath and 10m of gravel. Here is my first car: 5:3 gearing, 725gm Here is the results of the tests: Yes, I know - only 24.3km/h, but it's more than I would have ever expected a few months ago (when I thought that the top speed for Lego was 27km/h). I have some work to do...
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MLcad for making the digital model and LPub3D for turning it into PDF instructions. Note: if you want to use these programs, it's best to just download the LDraw all-in-one installer, because this includes some other programs that are essential for MLcad and LPub3D to work.
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Yes, especially when more than half of it goes into the groove of the pulley!