JoKo

There is a big fake engine I designed lately. Inspired by air-cooled airplane engines Radial 6 cylinders Over-head valves with pushrods and rockers 12 valves / 12 camshaft "Accurate" valves timing Crankshaft with counterweight Displacement: 43cm^3 / 84 stud^3 Bore & Stroke: 24 x 16mm / 3 x 2 studs 1140 pieces Good points: I'm happy with the valve timing system. I like the "snowflake" shaped gear train. The pushrods and rockers are nice to see working. One single rubber band around the timing module takes care of the valve spring job for the 12 valves altogether. The counterweight really helps reducing vibration and a small PF motor can run the engine up to 500 rpm. Bad points: The 6 cylinder design was dictated by Lego pieces however IRL an odd number of cylinders is the obvious choice for a single row engine. Because of the 4 stroke cycle an odd number of cylinders allows an ever firing order. And my 6 cylinder can not have an even firing order... I's no big deal because there is no actual fire and it is not visible when running "fast". But it is noticeable when it runs slow and upset my perfectionism... Instructions: I made building instructions with detailed steps to set the valve timing correctly. Before I publish instructions I'd like to have someone test it. So let me know if you're interested! Videos:

Sorry for late answer. No the panel is a black Lego piece with a rectangle of carbon fiber laminated on the outside. (90gsm 1K like the first link shared bs @allanp but not stabilized). I'm happy with the pattern alinement on the piece but I sanded a bit too much which made the pattern distortion near the edges and especially near the left corner. About the weight of carbon fiber I'd like to point a common misconception: CFRP is not that light as a material. If you replicate a Lego piece out of carbon fiber it will be 50% heavier. So if your goal is just weight saving and look you could make the wheel 90% 3D printed and laminate the flange with carbon fiber. It would be much easier to have a clean carbon pattern. I guess it's not what you want for your youtube vidéo as it would not be legit "carbon fiber Lego wheels". About loosing fingers in laborious sanding: Every hour spent to make the mold as smooth as possible is saved on the finishing of every piece getting out of this mold. And of course it will make demolding every piece more easy and less hazardous for the mold.

Yeah ! that's it! My model is still Penny -farthing but there is a cat and a butterfly on the trailer... Thanks!

I also realized I may have misinterpreted a rule: No animal allowed. I assumed it meant "please don't make an animal on a tracked base". But if it meant "no animal at all" I'll have to change a few things

I laughed at myself when I realized that I argued "tracked trailer makes no sense" while the trailer is pulled by a tracked penny-farthing... (so realistic!) So I stopped being lazy about it and found a way to make it work with tracks, that's what this contest is about after all! I'm eager to show you the result.

What if we say: The entry model has no wheeled trailer. Accessories like a wheeled trailer can be used in the video. Does it seem fair to you guys?

@Jim One late question about the rules: Can a tracked vehicle have a wheeled trailer? I mean a tracked trailer does not makes much sens IRL I guess. And traction on hard floor is not enough to power some mechanism on the trailer. Would this violate the no-halftrack rule?

Hi! This is a simple little 42205 Corvette alternate build. It is meant to look like F1 cars in the 1970's, with rear axle wider than the front, simple wings, and big air scoop. Features: V8 fake engine RWD with differential HOG steering Free building instructions: https://rebrickable.com/mocs/MOC-221015/Joko Technic Design/classic-f1-race-car/#details I built it in real life but have a problem with my phone currently so no photo for now... The new parts from 42205 are not yet in Studio. I tinkered something in PartDesigner. That's far from beautiful but clear enough for instructions. There is one unorthodox solution because of B-model limitation: the steering axle is connected to HOG with this system: (good enough for the torque needed)

This is really nice! The idea is great and well executed.

Thank you everyone for your votes! Congrats to @aeh5040 for his close win! Congrats to @Berthil and all the contestants that went out of our usual comfort zone for this contest. Thanks to @Jim and @Milan. This contest was great, I hope we'll see more unexpected themes in the future!

Thanks for reminding. Voted just in time. I really liked this contest theme.

one last video before deadline:

There are videos! You'll notice it already has its own Youtube channel (and Instagram) Please note that videos which are not linked here may not follow TC28 rules.

ROCK MACHINE “ Vehicles move your body, Rock'n'Roll moves your soul. “ This Machine is some kind of complex music box that can play "drums and guitar". It is made up of a music box mechanism and a removable music instrument that can be played manually on its own. This instrument is technically a harpsichord as it plucks strings when keys are pressed. It is a small harpsichord though so I named this instrument the "Harpy"! Mechanical and musical features: 8 strings harpsichord (Harpy) with boat hull as sound box (https://www.bricklink.com/v2/catalog/catalogitem.page?P=30215pb01#T=C&C=1) 128 lines loop harpsichord automaton 128 lines loop automated drum kit with kick (loader bucket), tom (red rim), snare drum (silver rim) and hi-hat (batcycle rim) Pneumatic mute system (drums and strings) with manal pump, two air tanks, pressure gauge Bar counter display (with coaxial counter-rotating fan) Adjustable drum-strings synchronization ( with differential and worm gear) Visual details: Red mystic spiral (hypnotic) Turbos (why not?) Minifig scale stage with automated lightshow Fake electric guitar Dimensions: Machine 86 x 86 x 24cm Harpy: 60 x 43 x 13cm Impressive numbers: This is the height of absurdity for a static non-vehicle but it uses 384 wide track links, eight 24mm wheels, eight 14.5mm tires, 3 turbos, two motorcycle rear wheels (1:5 and 1:8 ) and a cooling fan! The theoretical number of different "song" it can play with 8 notes is 3.9*10^115 (drums not included) Pictures: Video: The LEGO Rock Machine has it's own YouTube channel. Videos that are not linked here may not respect TC28 rules. Money for Nothing (Dire Straits cover): https://youtube.com/shorts/gHf9a6g1c2A?feature=share Cowboys From Hell (Pantera cover): https://youtube.com/shorts/4YSeqxyaCKA?feature=share Presentation video: Discussion topic: (more pictures on page 2) https://www.eurobricks.com/forum/forums/topic/200688-tc28-rock-machine-musical-contraption/page/2/#comments

The contest deadline is soon. I have to stop working on the machine and focus on video and music recording. The Machine is not finished but I have a feeling it will never stop evolving. The drums part need a deep update with non-lego elements for better sound and a "reading" mechanism with wheels as it already shows some wear. Also the music track needs to be wider with mounting pins on even number holes and music pins on odd number holes (like the Harpy track) I have to confess this is my favorite MOC because it is so unique and playing with it is on another level of fun than RC cars or display models. There are more pictures with backstage and a slomo shot of the claw mechanism

Thanks! I have upgraded the Machine with double length tracks so it can play longer loops. It makes the Machine 87cm tall. I should mention that I use a 9V DC transformer to power my Control+ hub. On a stationary build it makes no sense to use disposable batteries (and rechargable ones don't sum up to 9V) and it allows me to have a stable 9V like forever brand new batteries. In order to stay "within the rules" I used this trick that does'nt need any Lego piece modification ( the wire ends are tinned and stuck in the negative spring and positive side, the battery lid can't be closed.) It also means I can easily power it with 12V DC but that's obviously against TC28 rules, so we'll wait till march for that.

@lcvisser @Frequenzberater Thanks! @2GodBDGlory Yeah, at this point it also becomes a running joke for me. As sailing enthusiast and professional boatbuilder I already built two boats for not nautical Technic Contest. So I was stoked to find this perfect resonance piece. There is another short video with the drum kit and a pneumatic mute system. Have fun!

There is some news about my project! I finished the final version of the automated harpsichord. The mechanism is mostly unchanged. A little bit more reliable with the arms better guided in separate slots. I'm pleased with how it works, precise enough to play some iconic rock guitar riffs. It still misses a note sometimes and sound close to the ukulele but I think it now deserve the new name of Rock Machine. Therefore I changed the general machine design from minimalist to something more baroque (come on, there is a harpsichord...) and more glamourous with some mechanized decoration. I got a little bit of sound recording equipment. I now have small microphones that take the sound inside the resonance boat hull. It helps a lot to reduce the noise of the mechanism and motors. Enjoy the result!

Ok I finished building a new one with minimal studed parts and a piano-like frame. It still have fishing lines as strings 0.8 0.6 and 0.4 fluorocarbone. It works better than nylon guitar strings because they stretch very little and make the instrument more precise.

Hello! I was in France for my job but here am I, back to building. I built a music box mechanism for the harpsichord. Music is programed on a wide track and levers actuate the keys. I used small wheels (like 42147 truck ) that "read the music" and it has two purposes. It helps to make the mechanism quieter than the instrument and it allow long notes to be played because the wheels can roll on top of pins placed 1 stud apart. There is a video of the first proof of concept prototype. Please be forgiving

I rebuilt the drums module. It uses now only one track so it can be twice as long. It has 5 "arms " playing 4 different drums. The rhythm precision seems ok, it sounds fine but the bass drum (digger bucket 15x23) doesn't sound low enough to my taste. With a little bit of sound editing I can make it good enough so I'll keep it like this and focus on the next step: automating the harpsichord which requires 8 actuators and is more sensitive to mechanism noise. There is an example of the drums sound natural and edited. https://youtube.com/shorts/cJlF1l285bU?feature=share https://youtube.com/shorts/cJlF1l285bU?feature=share

Thanks, It's great for me to mix Lego Technic with music because I love both. Those are fishing lines... I tried nylon guitar strings mostly to have lower notes for playing a bass line. I faced the same issue as you, the frame is not stiff enough, bends and the keys get too much friction. That's the main improvement I want to make. I should build the frame like a piano, not like a guitar.

So the guitar/harpsichord evolved . It is now a double neck (double decker) with 8 strings and 8 key to play it. It works with small "claws" and a rubber piece to mute the strings that are not played. I would need to build the frame more rigid, it bends if the strings are to tight and it induces too much friction in the keys mechanism. I'm however confident that it can be automated. It will be the main feature of the machine. I don't quit the gear-diaphragm-gearbox system but I will have to simplify it back to 3-4 notes and not rely on this to play actual music.

New update: OK, the piano mechanism was not a good idea. It is so noisy and still doesn't make a string that loud. Pinching a string on the other hand has potential. I made a basic "guitar" and worked on a mechanism that can pinch a string and mute it. It works quite well. Sounds as good as a 5$ ukulele that gets out of tune in 3 minutes but I can tune it and now I am more confident that my machine will be able to play music, not just rhythm and noise

Thank you! Since the gearbox-gear-diaphragm is very hard to tune and can play only one note at the time I am studying piano mechanism. Since custom string are allowed it seems the obvious way to go if I want some audible music I copied the mechanism from this video and simplified a little bit https://youtu.be/uBEL3YVzMwk?si=CAfAnVwGbB7SCwlO