2GodBDGlory

I just realized I forgot a detail with my setup: I was using the medium-sized sprockets rather than the large ones because I didn't have enough track links. Therefore, I would have had an extra source of reduction.

When I built the set out of my collection, I did a very crude PF swap (not worthy of sharing), but I believe I used the exact same motor/gearing combination you originally had: the L reduced at 12:20 followed by planetary reduction. I was running it off of my 7.4V rechargeable camera battery, and it would move, but it struggled much more than it should have. I think you've made the right move adding more reduction!

Also, just so you know, it is possible to go into a user's profile and look at a list of every topic (thread) they've started, which is usually pretty close to a list of all their MOCs. It is a little hidden, though!

Yeah, a car-to-bipedal-robot transformation is very hard. You could try modeling a different sort of Transformer, though. I believe I recall seeing some 4-legged Transformers toys at one point.

Sounds cool! I agree that it is concerning whether or not those linear actuators can take the weight, so I imagine you'll either need to keep the weight quite low or come up with something a bit stronger. I don't think it's anything that can't be solved though!

So, as some of you may have gathered from posts in other topics, I've already been working on my entry for a while. It wasn't that I wanted to start three or four weeks early, but I took a gamble on guessing that the official contest rules would be published soon, and was wrong. Therefore, the first half of my WIP thread is essentially just me talking, without input from others. Also, I expect to finish well before the due date, so please don't feel like I started early in order to gain an advantage that way! Anyways, to date I've taken pictures and written out WIP posts four times. I guess I could stagger posting them to simulate a more normal contest entry, but that seems overly confusing, so I'm just going to rapid-fire my updates here: Update 1: For this contest, the first idea I had that I liked for an entry was a car transforming into an airplane. Not a car transforming into a flying car, but hopefully something more dramatic. The basic idea was that the car would shrink in width to attain the profile of something like a fighter jet, that some sort of rudder/elevator assembly would rise from the trunk, and that the hood and grille would split in half and fold out to create wings, revealing some sort of airplane-style nose underneath. Finally, I hoped to have a propeller fold out of the trunk as well to go on the back. If I could get that all sorted, I would move on to adding as many car/airplane functions as I could fit, such as a piston engine, gearbox, working ailerons, elevators, and rudders, and maybe even flaps and a variable-pitch propellor. I knew that the changing width would cause a lot of problems, so I started by working on the rear suspension and drive. After trying a silly idea with sliding transverse axles, I settled on the design seen here, with two parallel trailing arms for each wheel, with a planetary hub driven with an old female CV joint, as Zerobricks has demonstrated, followed by bevel gears and longitudinal shafts with CV/universal joints at each end, allowing for the axles to slide towards each other freely. I then started working on the actual mechanism to change the width, using two medium linear actuators per end of the car, geared together, and attached to an 11x15 frame that I could build the un-sliding parts of the car off of. Each LA only used four studs of its travel, for a total change in width of eight studs. I then extended the sliding “walls” of the car forwards and started working on the front suspension. Again, I couldn’t do a basic double-wishbone independent suspension design, because of the changing width, so I did a simple sliding-pillar design using the springs from hard shocks mounted on an axle at the steering pivot. I then mocked up a strange steering setup like the one you see here. The Z-shape of the links keeps the hubs parallel to each other regardless of the current width of the car, though the central control axle has to rotate when changing width or the car will automatically steer. At this point, I began thinking more thoroughly about how I was going to transform the front into a plane-esque nose, and realized that I would probably have to design my car to have a pointy nose as well. My plan for the aesthetic had been to simply build something that would work and then try to make it look decent, but I wasn’t happy with the idea of building a nose like this, since it would make the car look very strange. Then inspiration struck, and I decided to forget about designing my own car (which would very likely be very ugly), and instead model a classic Dodge Daytona or Plymouth Superbird, the only real cars I can think of with the nose shape I was after. Another plus was that I could commandeer the massive rear wing on the real cars and use it as a set of dual rudders and elevators, hopefully, which would be easier than having it pop out of the trunk. Also, the fact that the car is very long should help the proportions work out better as an airplane. A final advantage was that I would get to model a good-looking car that is also very boxy—a boon, since my mock-up chassis was already very boxy on the sides. The choice was then between the Daytona and the Superbird, but I chose the latter for three reasons. First, I’ve built two second-gen Dodge Chargers before but no Plymouths at all, and I wanted to do something different, Second, the taillight design on the Plymouth will likely work better with having the propeller fold out, and Third, the name SuperBird is perfect for a car/airplane. With this idea in mind, I printed some blueprints, extended the wheelbase to match, and installed a pair of linear actuators for the front half, connecting them to the rear. Update 2: The next thing I tackled with this MOC was trying to get the basic wing mechanism to work. I wanted the hood of the car to split in half and fold out to the sides, so I found a good pivot point for the wings and messed around with different gearings to get the wings to open the correct amount for the fixed number of rotations required to contract the car’s width. The best gearing for this turned out to be 1:24 worm gearing followed by 8:28 gearing with a small turntable. I also figured out a way to attach the wings from the sides to prevent their motion from interfering with the base of the windshield. I then moved forward, working to finalize the steering at the front. To do so, I added a second Z-shaped linkage to the steering to make the weird linkage sturdier. The linkage is run by a PF M-motor running a worm gear against an 8T gear (The worm is currently removed to make transforming the car during tests easier), which then drives a 12T gear against a 40T gear at the center of the main lever. As mentioned earlier, the change in width will steer the wheels to their maximum and beyond if not counteracted. I considered trying mechanical solutions to isolate these motions, but in the end, I think it will be far simpler and more reliable to mount the motor as I have here and just manually counter-steer as the transformation occurs. The only other change of note is the addition of a micro V8 piston engine under the hood, which will look dwarfed while in car mode, but which is all I can fit while in plane mode. I am now trying to figure out a linkage that will allow me to hook up the rudder(s) that I plan to add at the rear with the steering. Update 3: I’ve now spent a lot of time working out some of the aesthetics on the front. This has meant building the side of the pointy front, which will hinge in and out depending on mode. In car mode, it will be out parallel with the rest of the car, fitting under the hood/wing panels, while in plane mode, it will hinge inwards to create more of an aerodynamic cone shape on the front. I built some of the central aesthetics for plane mode (which will be covered up by the hood/wing when in car mode), evicted the PF M-motor from the front, and got the hinged panel to line up fairly well in both modes. This panel is extremely complicated in shape, though, made up of lots of small pieces. I suspect that it could be made much more elegantly and easily using Technic panels, but the #1/2 and #3/4 panels that would likely be used here don’t exist in LBG, and I am unwilling to buy a lot of parts in some other color to recolor this car. I do have some of these panels custom-painted into LBG, but I’m pretty sure painted parts are not allowed in the contest. I think my shape works well enough, it is just rough to the eye because of the random texture on it. The next step will probably be to mirror these bodywork things and hook up a linkage to work the pulling-in of these panels. Update 4: This update represents a lot of work. I still haven’t worked out the linkage for the pulling-in panels, but I’ve made a lot of progress, nonetheless. The thing I mainly started with was fleshing out the wing/hood panels, but then the advanced weight caused major problems with the wing-deploying system. I should have known that three 8T gears in a row driving the 28T turntable would never take that kind of force without prohibitive backlash, but I was set on using the turntable and this was the only way I could think of. Anyways, I tossed that whole system and rebuilt a much better one using a worm gear to directly drive two 40T gears, to which the wings are attached. It was very hard building this module, since not only the worm shaft, but also the steering shaft and the engine shaft had to traverse this space, one on top of the other. I just managed to get it all to fit, though! Before I trashed the 28T turntable setup, I had realized that I could revive my dreams for working control surfaces on the wings that I had previously given up on by running universal joints right over the center of the turntables. I essentially carried this system over, but decided that since I can only get one shaft out onto the wings, I would have to combine the ailerons and flaps into flaperons. This meant that the bevel gear housing in the middle could not be fixed to anything, since it will have to rotate on its axis to activate the flap function. Unfortunately, I was at my width limit, with no room for support between the bevel gear housing and the U-joint (SaperPL’s 3D-printed U-joint with integrated axles would have been a lifesaver). The best solution I could think of was to mount the bracket on the thin circular holes from minifigure back brackets. I’m not happy with the strength of this setup, so I’ll plan on improving it soon. Other than that, I’ll need to get around to making the linkage for those front panels, reinstall the A-pillar bases, attach the steering motor, and hook up the wing folding mechanism with the linear actuators for compressing the car. (A 32T gear would fit perfectly with just the right ratio. Grrr!) I’m starting to feel like the car has hit the tipping point where it is now too complex to ever work correctly, which happens to me a lot. Hopefully I’ll have the patience to work through the increasingly difficult challenges of packing the rest of the stuff in!

Update 5: Since my last update, my main focus has been on getting the side panels at the front to fold in correctly. First I got the complex gearing system set up, which was challenging given the very limited space: That 8T gear driven by the worm gear in the above picture runs the axle that drives the white 40T gear down here, which connects to the linkages that actually pull the panels in: Because I'm pulling the linkages from the center of the chassis at the same time as the center is drawing closer to the outsides (due to the linear actuators elsewhere) the total travel of the linkage has to be increased to compensate for this relative motion. I was having troubles with my older brick-built hood/wing and side panels catching on each other, so I took the opportunity to design much cleaner looking, stronger, and more Technic ones using pneumatic hoses, and redesigned the central "peak" to make it fit my new panels better. You can see the car and plane modes here: This model has proven to be very challenging, requiring a lot of rebuilds on certain parts. It's certainly a refreshing break from building more conventional cars where I design a system I expect will work, install it, and don't touch it again. This one takes thought! I'm not quite sure what the next step in this project will be. I'll probably make some tweaks to the side-panel-pull mechanism to enhance its reliability, but from there I suppose I could start working on the roof, which will have to have a retracting center section, or move into the back more.

The simplest way would be to download the Lego Powered Up app. This allows you to make custom profiles (including simple ones) and program things, but it takes a little bit of know-how. There should be good tutorials on YouTube on how to use the app.

Sariel has confirmed that in the comments

I just commented on Sariel's post to try and get clarification.

I don't know. It does look like a 0, but it is also a very odd shape for a 6. Also, the 0 set isn't supposed to be released until later, so I'm skeptical that it'll be reviewed that soon. I'm really looking forward for it, though, so I hope you're right!

Nice analysis! I'm not sure where this system would be practically applied, though, since torque-vectoring differentials and locking differentials seem to take less space and weight than this clever mechanical solution. Still, there may be some vehicles where this setup's durable but heavy extra driveshafts would be preferable to the more delicate locking/torque vectoring differentials. Either way, I really like this solution!

Nice work! I agree that the roof is nice. I dislike the way the olive color clashes with the red, though. Those wheel arches do exist in white from the Mindstorms Robot Inventor set, and would likely make the car look a lot better. Otherwise, good job!

They're not actually locked in this model. Rather than driving the differential from the 28T ring gear as usual, that gear is left to idle while the actual input comes from the 16T gear locked to the casing by the driving ring. Think of it like the 16/24T differential: There are two ring gears, but only one is being used.

Cool to see that concept actualized! Are you planning on programming actual autonomous driving?

Yes, I've noticed that! I'm super intrigued by this, because MouldKing already has a programming interface in it's app (which works with this battery), so all it needs is sensors and smart servos to use these extra wires, and it will have the better PF-based PU I described a couple summers ago on here, where there is full backwards compatibility and stackable plugs, as well as programmability. The low price, six ports, proportional (on four of six channels) physical remote, rechargeable battery, and studless design are icing on the cake, in my opinion.

I think you might be right on that! It definitely looks off-center, and off-center enough to allow for another one beside it.

Here's an idea for a dramatic transformation: Before: Nice, generic MOC After: Blackened blob of plastic Mechanism of transformation: Sketchy wiring using PF extension wires and 9V wires allowing one to short out one of the Lithium battery boxes (Should Lego have protection against this, use a rechargeable Lithium 9V battery in the old train box), causing an intensely hot fire to transform the model. Can I get a purist's opinion on this?

Hmm... Arguably, since the earth is moving relative to the universe, then everything on earth is moving (relative to the universe), and everything macroscopic on earth can transport at least an electron, so therefore essentially anything we want to build is a vehicle! Loopholes are fun.

I was kind of hoping it would be some high-powered Lego machine with a real blade cutting Technic models in half... This is clean and nice-looking, though!

I at least like the rules the way they are. Yes, it's a bit complicated, but it's already been questioned and explained. Allowing an extra motor just for more power allows people to build more complex transforming mechanisms with more moving parts without sacrificing their other motors or making it overly slow. It's true that limiting the motor count more would tend to promote smaller models; whether or not that is desirable is another question, though a legitimate one.

Nice job! I like the use of the black mudguards without the fender parts.

Thanks! You're right, it is a lot of force. They definitely do bend in when the car is expanding, but it seems that driving it forward just a little gets them to straighten out.

Sweet, thanks!

That's be great if you can find the time. Thanks for putting these contests together!