powerwindows83

I don't know why I thought to do this, but now I wish I had the resources to try it... Can you mimic a car's ECU in terms of engine management- using only vanilla bricks and sensors- well enough to make it run correctly? I'm talking about removing the car's ECU and all the sensors that provide engine feedback (ie. knock, cam position, map/maf, etc.), replacing them all with LEGO counterparts, then programming the NXT/EV3 bricks to properly manage the engine during normal and extreme driver inputs. Theoretically it should work, but I'd definitely get a kick out of someone with more money than myself trying this IRL! Yes, I know this is ultimately completely pointless.

I didn't see anything like this online anywhere so here goes: are there any mirrored/reversed pitch versions of standard Lego propellers out there or do I have to make my own? I've been building motorized boats recently to test propulsion methods, and the best small scale prop I've tested so far is the small 3-bladed prop (6041) placed on both sides of a technic cylinder (41531). I've been using the 40x20x7 hull since it's the only one I currently have that floats. https://imgur.com/a/JEUlSLY The problem with this setup and single-prop designs is that since they spin the same direction they turn the boat quite significantly. When launching from a standstill the force on the aft end is almost 45* from straight. This brings me to the question in the title: is there any third party source that makes Lego propellers but with mirrored pitch so I can make a counter-rotating design, or will I have to do some cutting and gluing on my own? Google is beyond useless with specifics as we know Thanks!

the two biggest issues ive had with these triangulated 4 link setups are that the vehicle doesnt support itself very well in regards to tilting because the spring geometry is always far enough off that it causes the vehicle to flop side to side with little resistance, and the other issue is axle wrap. youve snuck around both of these problems by having a negative unsprung weight thanks to that body style and the motor-on-axle setup, so i guess ill have to study your design a little more and figure out how to optimize it for the massive heavy trail rig chassis i always end up making. thanks!

is there any way to use this kind of setup with yellow springs, or is it kinda impossible to exchange out the springs currently on it with anything else and have it still work anywhere near that well?

as someone who doesnt own these hubs but might later on, what about drilling a tiny hole somewhere in the case to inject grease? if yes, make it a pluggable hole so its almost like a normal periodic oil change?

Hello all! I recently bought myself a BuWizz 2.0 and I've been experimenting with transmission designs using the new Chiron shifting bits and gears. I'm trying to figure out how to control a servo with the BuWizz unit in such a way that it only has full left, centered, and full right as options for a 3 speed transmission. The closest thing I can find is the light buttons in the control setup, but they only allow for center and full lock in one direction. Has anyone figured out a good way to control a servo like this or found a clean way around it? Thanks!

sounds like its not too far off, you just need the interest rekindled. its got potential!

if you threw a standard lego wheel on it and changed the gearing (or added a second XL motor to the other side) what was a failure about it?

i cant see it because im at work but boy does that sound expensive

also i would like to get my hands on some of those torsens to do some strength and deformation testing, but at $11 a pop thatd get expensive quickly :/

it appears from the pitch of the worms that it requires a helical gear and thus cant handle any lego ones... efferman would have to reply to confirm that though

as someone who really only makes prototype off roaders, i can tell you you want diffs in as many spots as you can fit them, and as many of them lockable as you can reasonably manage. if you need to delete them for design reasons, take the center out first, then the rear, then the front. suspension: easy rule of thumb: the more flex you have, the more diffs you want. the less flex you have, the more diffs youre gonna need to remove. a suspensionless chassis should have no diffs, while an unsprung pendular setup should have all of them. center diff: make a simple 4wd chassis with 3 diffs (locking center) and drive in a wide circle on carpet. note the motor smoothness and speed. then engage the locker and listen to the motor immediately start having to work. on top of that, notice how the circle starts getting much wider... very different handling characteristics, and thats just with the one diff removed. if your steering angle is down in the CV joint range then honestly dont bother with the center diff, but if you plan on significant steering angles on high grip surfaces then you definitely need one. also more diffs = happier U joints :) front/rear diffs: the axle diffs are quite a bit harder to make lockable, but it can be done and there are many designs on here that can be used or drawn from. the easiest and cheesiest method is using pneumatics. a slightly harder but more reliable way is to use a telescoping U joint setup to send drive from the locking motor in the chassis to the mechanism on the axle (assuming live axle setup. its much easier on an independent setup if width isnt a huge issue since the whole drivetrain is fixed). lastly, if space allows just stick the locking motor and mechanism directly on the axle. piece o cake! LSD options: i usually dont like using friction to do things with lego since its unreliable. but if you put all of your reduction between the center diff and the front/rear ones, the friction from the spider gears in the center diff is multiplied and can have a slight limited slip effect between the axles. this can also be noticed if theres enough reduction from portal axles, since they multiply the friction force from the axle diff gears. and if you desire all the LSD-ness, put a clutch and a regular 24t gear tied together across the outputs of a diff. youll be pretty hard pressed to get that stuck... extra info on diffs: when using the old 4L diff under load, always always always put something solid around the case to hold it together, like a thick key ring or something. the sides bow outwards really easily when torqued hard and will cause the spider gears inside it to skip. i find this diff type to be so irritating because of that ive pretty much stopped using them altogether in high torque applications. when using the new 3L diff always always always put a second 20t gear on the opposite side of the 5x7 case from the driving one. under very high loads the ring gear will slightly bend away from the 20t and cause it to skip. putting the second 20t on the other side eliminates this effect entirely so far as ive tested it. for exactly this reason, never use 92910 as a diff carrier if the model will see high torque since you cant put a secondary gear on it, and the force required to cause the diff/20t skip is enough to demolish the gears after just one skip. sorry for the wall of text :P

ummm why not? nice build! how did you get the drive to the wheels with that small a center section?

you could make the motor easily removable from the rear section and the wire from its connector, then just pop the motor into the next rear section and thread the wire back through possibly? also try messing around with half beam triangles and the U bracket (4558692 this thing...) with pins connecting them. with fairly little effort you can make a steering system with a u joint, and steering system thats only a little bit floppy (i care a lot about steering flop and i consider this design passing). the ground clearance under the design im referring to is pretty much the most you can possibly achieve, with just over one stud below the center being the lowest point. im at work thus not near LDD so i cant draw it for you, but the only issue i can imagine you might run into will be the overall height. but hey! engineering! :D

a little off topic, but it would be nice if TLG made air springs (airbags) like trucks have. just a short-throw high-volume flexible rubber accordion with a port on it