2GodBDGlory

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.

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!

Sweet, thanks!

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

When are you planning on putting up this contest, @Jim? It doesn't really matter, but I'm just excited about it!

Nice presentation! Rubber bands do work well for suspension. The front suspension looks quite unusual with the steering pivot set so far back from the wishbones. Is there a particular reason for that?

Yeah, those panels are what I'm most excited about.

I just got a 42026 Black Champion Racer pullback for free from a guy who pulled it out of a dumpster! The set is 100% complete, in great condition, even including the extra worm gear needed for the alternate model (Sadly, it's a late-build set with the 2L worm instead of the 3L one.) It's not an amazing set, but you can't beat free!

Come to think of it, the different design of the contacts and plug of the third-party ones could be just enough to make it work on them, but not on the Lego one. Perhaps they are a little tighter than the Lego ones, and so it will still just contact them, but not quite the Lego ones. I'd try @Doug72's solution.

That's really strange. I suppose you've tested it on multiple PF receivers? Standard Servo troubleshooting would probably be to check that all the contacts are bent out where they need to be, to see if the wire is wearing where it enters the motor (this would be seen if it worked with the cable bent some ways but not other ways), or opening it up and cleaning off the semicircular contacts with a pencil eraser. I just can't figure out why any of these issues would cause the difference between power supplies.

That's a strange problem! I've had many Servos break down, and have fixed several, but I'm not sure what would cause it to work with only those third-party controllers. The only thought that comes to mind is that I believe some of the knock-off servos would behave like that. Is yours an original Lego one?

Well, given that a single Buwizz costs more than the whole set, I'd assume that's worth about 5 or 6 times the original price! Great work, though!

There just might have been a few uses in very rare instances before, but now that we have the LBG 3L pin with the stop at the end, virtually all of those uses can be better served now. Now the only reasons I can imagine are for a strange aesthetic detail in a lime vehicle or for a situation that requires something in the shape of that leaf for a stop or something.

Yeah, I think the only way for high-performance stuff that won't destroy the plastic too quickly is light weight.

Well, I ain't the police, but I expect it is fine. The only real question is whether or not such a technique could be used in an official set, and I think it could. Sometimes installing parts requires a temporary slight bend, and sometimes Lego will put up with a slight bend on a part. If you want to make it slightly more legal, you could try using frictionless pins on both ends. Lego seems to think that their extra slack allows for slight bend, as in the long pointy panels on the front of the Volvo dumper. At the end of the day, though, I don't care a bit about whether a technique is legal.

Very interesting! I like the focus on good chassis and drivetrain design. The diagonal setup is quite unique and well worth experimenting with, though I expect it is too complex for widespread use on real machines, and too complex to beat a no-differential or locking differential setup on small, light RC cars. It's still a very intriguing concept, though!

Yeah, it has the sliding contacts on the plastic switch that run over the circuit board. I've had some get bent out of shape before, but I'm pretty sure I got it working eventually by trying to bend them back into shape. To take a look in there, you can take off the two screws on the side, and then yank unnaturally hard down on the bottom half that holds the batteries (pushing down on the PF plug on the top may help). If you get it apart, you should be able to take a look at the underside of the switch. Like Void_S says, though it is a very cheap part to replace, with working ones on Bricklink for under $2 USD.

I've got some MK ones. They are definitely stiffer and make very metallic sounds when banged together. They're not invincible, though--I twisted one to fibers under the brute power of my quasi-hobby motor geared down about 30x, but this is an extreme use case. I'd say they're between ABS and metal in strength, but a much better deal than metal.

Ok. I guess the question is how many revolutions you plan to put on that wheel in the lifetime of a MOC. If it's going to be a lot (either all at once or over time) wear might be a consideration, and if it is going to be fast, friction might be a consideration, but so long as it's slower and isn't going to be used on a regular basis I expect you'd be fine. It also does push the rim out at the top, giving the wheel a little camber. I guess it also comes down to style. I'm fine with a bit of quick-and-dirty on my MOCs so long as it works, but other people are more perfectionist, which is fine.

I think from this formidably expensive set alone, they would never, ever become affordable on Bricklink. Fortunately, they should be on B&P, and very likely in Technic sets too.

As long as the model is going to be slow, I probably wouldn't worry about it. At least, I've used it before without much trouble.

Are all those parts LBG (except for the turntable top)? I assume so, but they look a little more blue than usual. [EDIT: Never mind; they're obviously LBG in the set's images] The gear rack does look very cool! It is another step towards an ideal setup for planetary gearing in MOCs, though it isn't quite there yet. These are the planetary gearings I foresee working: (Planet:Sun:Planet) 24:12:24 20:20:20 16:28:28 12:36:12 A 14:32:14 ratio could also work, I think, but the 14T gear is in the past and the 32T gear is in the future (hopefully!)

Yeah, the potential added functionality would definitely be worth the spread costs between users. I do have to wonder whether it would be good business practice for either of those companies to provide him with their product for free in order to add it to the app. The small cost to them would seemingly be earned back easily through the added potential for the product.

Cool mods! Also, I don't think I've ever seen anyone else post photos like that on here before, but it is quite convenient to browse them!