2GodBDGlory

You can also jam a 2L axle extender into it, which is strong but questionable.

Nice job! It's amazing how good it looks while still driving. How does it return to an upright position after steering?

Rats! I don't know why I keep accidentally submitting stuff before I'm ready! Please ignore this for now... Here is my finished entry to TC21, a Plymouth Superbird that can transform into an airplane of sorts! The idea here was to build something at least moderately plausible to exist and work in real life, with as many moving parts in the transformation as possible, and as much auxiliary functionality as I could fit. As expected, the model ended up being fearsomely complex, which had the natural result of making it fairly unreliable. However, this is a tradeoff I'm usually willing to make for the more interesting design challenges it offers. Features: Aesthetics Transformation Drive with piston engine Steering with rudders Full suspension Flaperons Aesthetics: I think the car mode looked ok. I'm never much at making bodyworks, and the transformation gave me a whole different set of constraints to follow. Nonetheless, the car is both boxy and easily recognizable, so it didn't turn out too badly. I also printed some custom stickers to emulate the decals on the real car. The airplane part of it didn't have to match anything in real life, which was nice, but it certainly didn't look like any real airplane. I'm fine with that, though, since the hope was really just to replicate a hypothetical way that a car could have a flying mode, and I think I succeeded there. A real car/plane would have to balance the complexity of the transformation mechanism with the aerodynamics of the resulting airplane, and I think my model looks like a reasonable compromise between the two. Transformation: The transformation was powered by a single PF L-motor in the rear of the car, and moved five main segments. These were: 1. The wings 2. The width change 3. The "nose pinching" 4. The roof lowering 5. The jet deployment. It took a bit of time to complete the transformation, and had to be punctuated by steering to counteract the relative motion between the motor and the wheels and driving to help the wheels to slide side-to-side. The hardest function to keep working was the jet deployment, but with the right tuning it all worked tolerably reliably. The wings were attached to two 40T gears, which were driven by a worm gear between them. It was tricky to work the A-pillars around them, but it ended up being quite reliable. The width change was done using four medium linear actuators placed in two pairs between the axles (in retrospect, I think it would have been better to try to fit the second pair behind the rear axle.) This too was reliable, but the wheels would drag opposing the motion, requiring the operator to drive the car forwards and backwards to allow them to work there way to where they need to be. The "nose pinching" used a convoluted drivetrain to run a 40T gear on the bottom of the front of the car, pulling links inwards to pull the pointed sides of the car inwards to a pointy nose in the airplane mode. Because the sides were moving in relative to the links in the transformation, I had to increase the link travel to compensate. The roof lowering used a basic slip clutch and linkage setup to pull the center of the roof down immediately before transforming into the airplane mode, allowing the two sides of the roof to cover it. In returning to the car mode, it would press up against the roof until there was room for it to actually move up. The jet deployment was especially challenging. It was driven by a carefully tuned slip-clutch using a Bionicle ball-and-socket setup, followed by a bevel gear and two long rubber bands in parallel. These rotated the assembly with the jet on one side and the center of the rear bodywork on the other. It had to push up a central section of the rear deck, which was rubber-band assisted to help it deal with the weight. Drive: Although the car looks fairly large, I was really limited to its size in the airplane mode, so space was at a premium. The only motor I ended up being able to fit for drive was a PF M-motor, but the drivetrain was fairly efficient (No gearbox!), and the car didn't need speed, so it worked fine. It drove a 8:24 reduction, followed by two shafts geared to each other with 16T gears. These drove two independent shafts to each rear wheel, using extendable driveshaft sections using halves of shock absorbers. These were necessary to allow the track width to change while still driving the wheels. They were followed by bevel gears and planetary hubs driven using Zerobrick's method of sticking an old female CV joint half into it. Additionally, I stuffed a micro V8 piston engine into the front of the car. It was driven by a ridiculous 20:12:16:8 geartrain, with all gears but the 16T at a half-stud offset from the rest of the car. It worked, though! Steering: Steering was also done with a PF M-motor, also in tight quarters. It drove a complicated drivetrain of 12:24:8 followed by universal joints, followed by 8:8, followed by a 1:8 worm reduction, followed by 12:40 reduction. The 40T gear had a strange Z-shaped linkage attached to it. The central bar of the Z was attached directly to the gear, causing the two flat lines to pull in and out on the two steering arms. Actually, to increase stability, there was an independent backwards Z linkage just below this one. The weirdness was necessary to allow the motor to steer the wheels regardless of the width between them. As mentioned earlier, it had the unfortunate side effect of automatically steering as the model changed width, but this could easily be counteracted with the controller. Beyond this, I hooked up levers on the top of the steering pivot, which pushed/pulled long longitudinal axles, which moved other levers at the rear connected to twin rudders built into the sides of the wing at the rear. This was intended to allow the pilot directional control in flight, but unfortunately had to be a counter-steering setup, rather than the in-phase setup that is preferable at the high speeds where aerodynamics actually starts making a difference. Suspension: The suspension was also complicated by the changing track width. Most ordinary suspension setups only work with a fixed width, so I had to got to be creative! The rear has what I would describe as a longitudinal double wishbone setup, with two roughly parallel links connecting the hub with the frame. A hard shock was crammed against the edge of the bodywork, but proved too soft, so I added a loose soft shock to the sliding vertical axle responsible for preventing transverse motion of the hub. The front suspension was slightly more conventional, being a sliding-pillar design used on vintage cars (And Caterhams and/or Morgans today, I believe), with the hub being sprung on a physical support coinciding with the steering pivot. My setup used a loose hard spring per wheel, and worked quite reliably. Flaperons: I had always wanted to include all the control surfaces an airplane could have, but it became increasingly clear that I could only get one driveshaft into the wings. Rather than choose ailerons or flaps, I decided to try the combination of them known as flaperons. To do so, I hooked up the flaps to a central joystick using universal joints. Moving the stick forwards and backwards would move both sides together as flaps, while moving it side to side would rotate the bevel gears in the mechanism to make them rotate opposite directions as ailerons. Because of width constraints, I had to mount the bevel gear housing on minifigure neck brackets! This function ended up being simple but satisfying. (By the way, I regrettably had to give up on adding a working elevator.) Overall, I was satisfied with the result. I managed to pack a lot of functions into the model, and a lot of them were new, exciting challenges for me! Transformation starts at 4:55 in the video More images can be seen here: https://bricksafe.com/pages/2GodBDGlory/transforming-plymouth-superbird

I am pleased to make my final update and presentation of this model! Update: After my last post, I stayed up late finding out ways of fitting the 8878 battery that didn't work, and went to bed with merely an idea. The next afternoon was spent executing it, and the evening in filming. So, the plan to fit the transformation motor on the bottom and fit the battery in its place didn't work. I simply couldn't come up with a strong way to attach the motor with enough gear reduction in the available space, so I left it where it was. However, by rearranging some of the linkages in the roof-lifting function, I just managed to free up the 4x5 space needed to slot in the battery. It actually worked quite well there, but it required me to relocate the receivers, which was quite challenging in this tight model. One sat in the rear window, in a logical if somewhat ugly place, while the other was jammed in the underbody in some of the space the battery used to use. Anyways, I got it all together and working! I got all the functions working on camera except one: The jet retracting as it transforms into car mode. This had generally worked in my testing, though not as reliably as I would have liked. However, while I was filming, one of the two rubber bands driving it snapped, and I didn't have any spares of the necessary tightness to replace it with. I'll present it in another post in ~30 minutes, because I'd like to keep the update and the final presentation separate.

The model looks like it'll be pretty cool! Is there any reason you are preferring the Power Puller rims over newer ones? My TC21 entry also has varying width; my solution to drive it was to put bevel gears on the wheel hubs to make the drive longitudinal, and then use long axles with CV/U joints at each ends. This way, when it contracted, I only had to deal with a relatively small amount of length in the longitudinal axles. Perhaps something like this could work here, but maybe you need something more compact. Also, it looks like only one of your wheels moves relative to the body, which may change things.

Interesting! I don't know much about how circuit board components, so could you explain how you knew the driver was broken?

Very nice overall! I'm not convinced about the rear window, though--it looks too solid to me, like there'd be no rear visibility, which would be unusual for a front-engine car. Maybe that's not something you can change, but it's not a big deal.

I think this part would have to have integrated pins to work, which would limit it's versatility, but it could still be useful. I agree, though, that I'd much rather have functional parts than panels!

That's neat; I'll have to try it sometime!

I've used an inkjet printer to make stickers before by printing on sheets of labels (like would be used on envelopes.) It's not great, and I expect there are better solutions, but it works.

Ok, mini-update: I got my Lithium 9Vs today, and tried the MOC out with it. Sadly, it doesn't work. The batteries themselves are great, and I'm sure I'll find uses for them, but after trying a lot of tests, I think the root problem is the way I'm running the receivers off of their output from the 9V battery box. I could fix this using the old aluminum-foil trick, but contests require purity... (Metallic Lego stickers are not conductive, by the way!) Anyways, I've got a rough idea to put my Lego rechargeable box where the transformation L-motor is now, and then hook up the L-motor where the battery once was. I think it should all be possible--the issue is just time. I've only got 39 hours before I leave my Lego behind and go home for Christmas, and I've got other things to do, like eat, sleep, go to class, do homework, go to the library, and pack. Here's hoping I can pull it all off in time! I guess I should stop wasting time on here now...

As for the video, I think you might have made a mistake with your links. Is there supposed to be one showing it driving? I see you have an identical link for both the general video and the driving concept, so I think you might have copied the wrong one for the general video. I'd love to see it work, though!

Very neat! It's great that that Friends part fits in those tires like that. Is it stable enough to actually drive around?

Yeah, it is odd! And I watch trucks, too! I'll see flatbeds (Especially because our road salt rusts out the original ones early), toolboxes, and various specialized commercial beds, but never anything quite like this.

I'm glad to see it on the actual set! I can't say I've ever seen a bed like that in North America, making it slightly ironic to put it on a truck that is (I believe) exclusive to North America, but that also makes it cooler, I think!

Is that a green O-frame in the roof?

I like the way it looks, but I'm having a hard time imagining what such a tray would look like in real life. Is it essentially replacing the bed with a solid drawer system, which can then have stuff strapped on top, plus the tall toolbox at the front?

Nice to see those standard blue parts! It's a very pleasant color, and I hope they'll put it in a 1:8 supercar someday (probably not for a bit, though, because of the similar Bugatti).

I for one would be curious!

I wonder how it would work out if Lego went back to its old Tech Play/Tech Build monikers for play-focused and tech-focused sets, perhaps with different set number prefixes again. Though I guess a lot of 18+ sets wouldn't fit in either... Probably they've got their business case figured out, but it would potentially be less confusing!

Looks pretty solid to me! ie. Prime late-night-boredom throw-a-set-together-and-play-with material!

I guess we can hope! The 2016 Porsche 911 could be seen as an analogue in starting a line, and was itself considerably less functional than its successors.

The issue with putting a pullback in a Creator Expert car is that those models don't have the durability of a good Technic model, which is a key thing when they're getting smashed into walls with a pullback motor...

Man this is going to be cool! So much RC complexity, such good looks, and such large scale! I like it a lot!

One of those cases where B&P is a lifesaver! Imagine if five $800 sets had had to die to make that!