lmdesigner42

All finished! I successfully shrunk the camshaft to 2 studs and lowered the V4 to make the hood at the proper height. This resulted in a few other internal changes such as 8:16:8 gearing for the steering and a 2L section of ribbed hose in the drive shaft to accommodate the 0.5 stud offset. Some comparison pictures are included below with my TC22 entry and the 8081 Extreme Cruiser. My 8081 is rather heavily modified inside, but the exterior is unchanged. I am happy to have captured important visual details such as the distinctive headlights and taillights, the license plates, red stripes, and blue/grey seats, but some smaller things like the stickered red stripes on the roof are missing. The steering is also routed to the HOG with two yellow knob gears like in the original. I feel like the miniature version rides about 0.5 studs too low, due to a combination of play in the suspension and the slightly too thick fenders, but it’s not worth it to me to figure out a way to redesign the chassis to eliminate that. All the pictures are on Bricksafe. Next up is the entry post.

Another progress update. I extended the wheelbase by 1 stud, 0.5 was not enough, and a gear train now routes the steering axle around the driveshaft. Most of the bodywork is done, except for the fenders and headlights. The hood now fits around the engine, but is 1 stud too tall since clearance is needed for the pistons (last pic). This rather hurts the looks of the front, so I am going to try and replace the camshaft with a smaller one in order to drop the engine and hood 1 stud.

I wanted to use the 16 tooth clutch gear as you suggested at first, since that was what the original 8081 had, but there wasn't enough space lengthwise to move the u-joint (+ cv joint) back. Since I'm going to try and move the engine forwards anyway, the clutch gear is definitely something to revisit. I liked the lever because it was simple, compact, and the steering shaft barely rotates anyway, but it does rub the driveshaft a little and takes away space for mounting the seats, as you mentioned. Now that I think of it, the u-joint could be replaced with 8 tooth gears which would make space for the clutch gear. Thanks for the suggestion!

I’ve assembled more of the chassis/body, and have run into a small problem, the hood panels are interfering with the engine block and as a result the hood is too high. Hopefully this is visible in the below picture (the perspective isn't very good). There isn’t an easy solution, since both the V4 and 3x7 hood panels are important for the functions and aesthetics of 8081. There is only 1 stud for structural support between the engine and the front suspension at the moment, but I am thinking that if I thin that support to 0.5 studs, and stretch the wheelbase 0.5 studs (which is actually exactly to scale) I can move the engine forward 1 stud and it will no longer interfere with the hood. Any other suggestions are welcome. Another challenge was crossing over the steering and drive shafts in the center of the chassis. Eventually I came up with a small linkage to route the steering around the driveshaft. There is only 3 studs of width available in the center of the chassis, since 2 studs are needed on either side for the seats.

Thanks for the kind words, @Thirdwigg. I hope it turns out too. The fake engine is going to go behind the front axle, I'm actually going to integrate it so that the light gray L-beams in the first picture become the front engine block support. I am concerned about the size of the engine too. The steering shaft, crankshaft, and pistons stack to a height of ~5.5 studs, and the hood is 6 studs tall in scale, so it will be tight.

Yes, I saw your new topic. I’ll try to come up with a better name. The front axle is nice and small, but it was really hard to get the steering links to fit, had to use a bar with towball. I made some more progress, with a start on the chassis and some of the key bodywork elements. I narrowed the axles by 1 stud by removing the half bushes to bring it closer to the right scale. As a side benefit, the rear half-shafts are now secured with a half bush. I also made a mini V4, using crankshaft parts for yellow pistons. The next challenge is fitting all the various functions together with strong enough connections.

According to Sariel the hole is 3.5 studs deep (Zetros review), which should fit your setup.

Those axles are looking pretty capable, would a sliding CV joint help (77590)?

For this contest, I decided to shrink one of my favourite technic sets, 8081 Extreme Cruiser. Using 43 mm balloon tires, with a similar profile to the originals, the scale is about 60%. I plan to replicate all of the features from the original, including the suspension and the fake V4, which will be a first for me at this scale. The overall goal is to imitate the colour choices and “cuteness” of the original, using some of the new small panels. So far, the rear axle is done, and I have designed a steered and independently suspended 7-stud wide front axle. The next step is figuring out how to add springs…

IMO one of the best ways to figure out if a gearbox concept will work is physical building and error, but theorizing is fun too . I wonder what the second stepper gear (third photo) is used for?

I think this is the best year ever for Technic in terms of new parts. I can see a lot of Pick a Brick orders for the new transmission parts once they become available, it feels like a repeat of 2018 and 42083. 42159 also has 3 recolours in the gold large motorcycle shocks, black motorcycle hubs, and yellow rear shock.

That's an ambitious amount of shrinkage! Rough-terrain cranes are difficult to model because their real-life counterparts are already so compact. I can't wait to see what solutions you come up with.

Really nice progress! I briefly considered trying to shrink the Arocs, it's a very worthy set, but I never would have attempted going as small as you are. Great work on the steered and suspended front axles, I look forward to seeing the final product. About the outriggers, could you tie a string to the inside end to limit them?

A beautiful MOC with a superb level of detail! Looks just like a hot wheels car I used to have.

Having two separate drive motors will also make it drive more smoothly on a flat surface, without the need for a center differential.

Those rear axles are looking good so far! How strong is the flexible "leaf spring" you built? Going off the first picture, I would strongly attach the central pin holes of the grey links to the chassis as the main pivot points, and maybe lower them and add some braces on the axles to keep the ball joints from popping out. Then add some transverse panhard rods and extra longitudinal links to stabilize everything. That's just a suggestion though, there are many ways to make a great set of live axles!

Great work on the body shaping and doors! This train part might be helpful for the headlights.

Another amazing model! It's great to see the 3x13 curved panels implemented as leaf springs. Are they fixed to the frame at both ends, or is one side attached to a rotating link/shackle (https://en.wikipedia.org/wiki/Leaf_spring)? I can't tell for sure from the pictures.

The multiple steering modes is a really cool addition. Is it possible that the 12 tooth gear is connected to an assembly of 3 bevel gears and a bracket, so that rocking the gear back and forth makes the outputs rotate in the same direction, while turning the gear makes them rotate in opposite directions? Rocking the gear would then cause turn-in-place, while rotating it would cause normal steer.

Looks like a great plan for an improved truck trial! Some thoughts: I tried the 28 tooth idler setup as @2GodBDGlory described, and I found it had a lot of friction. Maybe that can be reduced through lubrication though. Also, be careful applying too much torque to the rack and pinion setup shown in your picture. I drove one like that with a PF M-motor geared down 9:1, and rather than stall, the 12 tooth double bevel gears skipped on the rack at full lock, even with bracing. Reducing the gearing to 5:1 fixed the issue. Anyway, best of luck with your build, and I look forward to seeing what you come up with!

Are you sure? 42039 had two geared manual functions (opening doors and back) which could be optionally motorized with PF. The recently trending licensed sets in the same size (RSR and Ferrari) didn't have that much, although maybe this year's Ford GT is setting a different trend with it's additional functionality. I'm definitely getting some 42039 vibes with the styling though.

All finished! The final build ended up being pretty large, and used a lot of black parts and panels. I had to order a few more from Bricklink. The size was needed to fit the two main features, the illuminated spinning engines and the folding landing gear. The rear set of landing gear used two 6x6 dishes, and with a central beam, a half stud of clearance on either side and two more support beams on either side, at total width of 17 studs was needed. 8 studs of hood height fit the folded landing gear and V12, and other dimensions were roughly scaled to similar proportions as the Lunar Limo set. The doors are spring-loaded gull-wings, and the trunk opens. Strategic use of panels and frames help maintain structural integrity despite the massive holes in the floor for the landing gear. It is possible to pickup by the rear windows, although the front roof is weak. It sits on the landing gear no problem. The landing gear was probably the toughest part since I wanted everything to fold into a completely smooth bottom. I was mostly successful, with a few 8-tooth gears poking out and a few small gaps for a gear and a linkage. The below photos show the unfolding sequence. There are two legs at the rear, locked together, and one at the front. Each leg rotates out ~150 degrees using a worm and 8-tooth gear. I originally tried a linkage, but the range of motion was too large to be compact and reliable. There are two covers back-to-back in the center, connected by more 8-tooth gears. They open in synch with the rest of the landing gear, but operate about twice as fast, with an opening and closing cycle controlled by a linkage and another worm gear. The crank (on the right behind bodywork) rotates from 12 o’clock – 9 o’clock – 6 o’clock making the covers go close – open – close via the linkage and 24t gear above the covers. This is shown in the video at the end. Another important feature is the 8x spring-loaded shooters on the front wings. They are synchronized to fire in 2 volleys of 4 shots, 2 per side, by some internal gears and cams. There is also a pullback motor stuffed inside to reset the cams. The last feature has to do with the story behind the model. It looks like a big, stealthy getaway space car, but it hides a secret. The hood ornament rotates to reveal a Space Police badge, a hidden siren flips out of the roof, and the lasers can rotate to turn into freeze-rays. Is it an undercover Space Police vehicle? Or a criminal trying to fool the law? You get to decide! Feature video: More pictures available on Bricksafe: https://www.bricksafe.com/pages/lmdesigner42/undercover-space-car

Entry name: Undercover Space Car Side: Space Police? Functions: Illuminated, spinning engines + V12 Flush-folding landing gear with synchronized covers 8 spring-loaded shooters with gear operation Hidden siren, Space Police badge, and flippable lasers Spring-loaded gull-wing doors Opening trunk

Love the compact suspension design with all the small links! I tried building something similar a few years ago and found that the soft shocks were too hard for such a small model when they were positioned vertically. Angling them is a great solution.

Progress on my entry has been pretty slow, but I have finished the rear wings/engines and made a number of functional and aesthetic elements. Hopefully it will be finished in time for the contest, but if not, that’s fine too. The overall design is heavily inspired by 5984 Lunar Limo, with a high-powered V12, front/rear angled winglets, and a valuable 8878 battery in the trunk. But as the entry name suggests, there are details that make this an undercover Space Police vessel. The hood ornament rotates to reveal a Space Police badge, and the front laser cannons also rotate to become freeze-rays. I’m also thinking of a flip-out siren on the roof. On the front wings, there are a total of 8 spring-loaded shooters launched in 2 waves by a lever and cam mechanism. The 4 winglets are attached at an angle using bars (or a shovel!) since a regular pin/axle would be stressed. Red is a temporary colour, they will be switched to black later. The next step is to complete the landing gear mechanism, since that will form the core of the center and chassis.