Davidz90

...and here's the inline-4. Wire management is a nightmare and I'll definitely need to properly solder everything together, but it works! The only issue is that after few minutes, coils get quite toasty (70 degree C or so). I tried to reduce voltage from 12 to 9 volts, but then there's not enough power to run.

Thanks! I'm working on a 4 cylinder variant right now. My plan is to build 1920's style car with this engine (something along the lines of Fiat S76).

While I'm not a fan of this set, I wouldn't complain about getting such a gift . I'm not sure if this one has been already posted, someone used the yellow threads+longer booms here:

I found a way to simplify and improve the design. Now current is passed through solenoid core. As the lever reaches its lowest position, it closes the circuit. Solenoid pushes the lever, maintaining the contact until it reaches maximum extension. Lever continues its motion a little further, opening the circuit.

Haha yeah, it is as sketchy as it gets. I wonder if anyone tried to use Lego piston engine parts like this; in principle, it should be simple to glue small magnets to the pistons and wrap the cylinders with coils.

A little proof of concept of using electromagnet as a piston in combustion/steam engine model. My goal was to recreate the cool looks and sounds of pneumatic engines, but without the hassle of air compressors or huge air tanks. One particular challenge I had to overcome was a very short stroke of the electromagnet (5mm) which necessitated the use of additional lever to attach it to a crankshaft. Another problem was turning the current on/off - all switches I tested had too much friction, so in the end I'm simply bringing two wires together. Not sure how long will they survive with all the arcing, though... Whole thing is terribly inefficient (uses almost 2 watts of power and produces close to 0 torque), so I uppose that it is good only as a display model.

Considering the large radius, this amount of misalignment is negligible. I've built this assembly just now, works fine.

Boeing X-37, Northrop Grumman Pegasus, Dream Chaser, maybe sometime in the future Skylon. Very excited for the orrery!

Heah, hard to call this a mod XD Building took about 3 days, mostly the base. Whole thing is very minimalistic and skeletal (I don't have that many large frames) and a bit larger than it really should be with this truss design. When I complete all the rigging, I'll test the lifting capacity but I don't anticipate more than 1 kg. One thing I noticed is that it is advantageous to make the ring on which superstructure rotates as flat as possible. I have only a single circular rack in the base and 6 ball pins sticking out of superstructure, riding in the gear rack ridge. While this has a higher friction than rollers like in Lego set, whole assembly is a lot flatter and less prone to bending. Also, due to stability reasons my slewing speed is very slow anyway, so a bit extra friction doesn't hurt.

Here it is :) (still work in progress but 80% done) With enough gearing down, single m motor is capable of powering this monstrosity, although at a speed that is somewhere between glaciers and tectonic plates.

I see. Yes, that is a considerable advantage.

Ideally, they could cost around the same as 3x19 frames (somewhat similar size and complexity), but I'm afraid they will be much more expensive. I suppose that it could be cheaper to just rebulild all the booms with regular liftarms. For example lattice structure from 42042 set has the same cross-section and is probably not that dramatically weaker.

Wow, that's ingenious! Interesting solution to the problem of motor shortage. I guess another possible way would be a distribution gearbox; one motor operates wave selector, one is the input, several outputs move valves through slip clutches.

I'm doing exactly that right now, although at a slightly larger scale; so far it seems to work well, although with a single M motor (that's all I have), the drive has two 1:24 reductions and a rather glacial speed (which is accurate so no problem for me). Not sure if that still counts as a mod when I'm just building it from ground up with the parts I have. So yeah, this will be a case study of recreating stuff from scratch indeed.

Haha, you can count me in the "making my own crane out of disappointment with the set" club as well. Working on something right now :) crane by David_Z1, on Flickr Back on topic, I'm surprised how fast all the functions work; they still apparently have plenty of power, but I expected the motors to be more geared down, for a more realistic speed.

I can't understand why the signal from tilt sensor is not used to move counterweight forward/backward to keep the crane level. At least that's how I unerstand the real thing works. Big missed opportunity here. The problem is that the booms are like 50% shorter and there is no second counterweight. Seems like that is how it was supposed to look, but designers ran into some serious strength/stability problems.

Very cool! Looks way better than the upcoming set. I plan to build something similar, will definitely borrow some engineering solutions from this. What is the weakspot defining the load limit?

There is a little fun fact I came across: the actuators moving the mirrors in JWST were prototyped with Lego! Specifically, when watching this documentary on them: I noticed that first comment on this video is from Robert Warden, who designed these devices. To quote: "Robert Warden here. I wrote the paper back in 2006. I just wanted to say how impressed I am with your reverse engineering! Your graphics and description are very well done. Back then, we didn't have easy access to 3D printers, so I built the first model out of Legos, which is still on my desk! Wishing you all the best - Bob" He also provided a video of this Lego model:

Sorry, I don't have any images. But basically, I mean that the worm gear from Lego City 60372 Police Training Academy set works both ways: normal, e.g. you rotate the worm and matching brick slides along it and reversed: you push the brick and worm rotates. Platform could attached to this worm gear and matching brick would stay on the ground. By pushing platform up/down, we cause it to rotate automatically.

How much space is available below the platform? If there is enough, one could use part 73763 (Worm Screw 6L) and attach it to the middle of the platform, pointing down and going through matching brick. This part has a shallower angle than regular worm gear, so pushing platform up (by whatever means, for example scissor lift you mentioned) will automatically rotate it.

A new large project. Clock powered by a synchronous motor: A 230V, 50Hz motor in the base provides very steady 5 rpm output. That is used to lift two levers. The falling levers power the clock. The system is self-regulating: if the pendulum is lagging, levers are lifted higher, producing more torque and speeding up the pendulum. As a result, the accuracy is astonishing; I couldn't measure any error after 5 days of running (I don't have seconds hand so it is possible that there was some error of under 30 seconds).

Very interesting project! I think that it could work much better if the wheels holding the bars on both ends were doubled. That could solve the issue of the bars not being parallel.

I'm very excited for these new pieces, but not for gearbox reasons. For example, the new 24T gear can be used for a very compact clock hands assembly like this: Hands by David_Z1, on Flickr where minute hand is on the axle and hours hand (with 1:12 reduction) would be attached to the new gear (20T placeholder is used in the image). Now if only they could finally make 32T gear...

Yeah, seen this one as well. Astonishing. Update to the calendar mechanism, now it has its own power source to avoid straining the clock mechanism.

Nice! Quite a compact way to implement 3 hands. I suppose that the part with 3-sided star connector on the second photo is the escapement? You might want to try this one: or this one: or this one: All of them are super efficient (necessary power source is on the order of one kilogram falling 10 cm per hour), reliable and need relatively little fine tuning to make them work right.