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Void_S posted a topic in LEGO Technic and Model TeamHello everybody and let me present my version of a modified 42005 Monster Truck. It was my second set after my "dark age", that I've bought many years ago, after 42029 as supplementary set with a lot of useful pieces and planned to use for a live axle suspension and some other features for 42029 model. However, I liked the set as a simple and functional model and re-assembled it several times. Here is the model and later I'll provide the all details: A month ago, when I tired of infinite attempts to turn 41999 into a Muscle Car (the chassis isn't rigid enough, but I already did a great progress and hopefully will share it once) I returned to this model and set the task to motorize it adding 4WD, but keeping 4 wheels steering and current suspension (keep the original construction as possible as I can). First, I've analyzed the all existing attempts that I could find over EB, Rebrickable and YouTube and it happens that there were several MODs by different authors: First of all, it's @Splat’s MOD with all steered and driven axles (see topic here). I see no reason to duplicate its description, so let me just note that he saved the necessary features with adding Servo + L-Motor mounted under the hood and trunk. The chassis configuration is 4x4/4 or 4WD-4WS. It’s the best motorized model, I think, because of amazing simplicity and performance, but unfortunately it has a kind of “articulated” steering that isn't real, so was trying to made a "real" 4WD-4WS version, using this model as reference. Another one is Jan Dvorak’s (is he on EB?) MOD with all original features supplemented by on-axle L-Motor that drives the rear wheels and Servo for the 4WS. He added an additional 5X7 frame with differential that provided a necessary rigidness. The chassis configuration is 4x2/4 or RWD-4WS. Personally I don't like such a long axle sub-frame. However I've found a good idea of vertical gears inside the central shaft. The third one is @codefox421's MOD, inspired by Splat’s version, with the original front axle and non-steered custom rear axle with on-axle L-Motor. His custom rear axle, based on two portal hubs, is a quite compact and simple, but has no steering. The chassis configuration is 4x2/2 or RWD-FWS. It looks trial-ready with the portal hubs, but it's nearly impossible to add the steering here, so I got nothing from this model. An unusual @Tommy Styrvoky's MOD with an interesting feature: he modified the front axle, not the rear one, by adding a solid drivetrain with worm gear and on-axle M-Motor, so result is a front-wheels driven Monster Truck with oversized fake engine. The chassis configuration is 4x2/4 or FWD-4WS. Very aggressive! WRRRRR Daniel Wirasantosa’s (is he on EB?) MOD that differs from the previous ones by using of chassis-mounted L-Motor that drives the rear axle (that has a bit low ground clearance due to the 5x7 frame) and, moreover, he used a custom steering shaft that comes directly to the steering rack. The chassis configuration is 4x2/2 or RWD-FWS. Starting this version, I got a more or less defined plan: 4WD with off-axle (chassis-mounted) L-Motor that drives the both axles through the existing “drivetrain” (former steering shaft) and the off-axle Servo that steers the both axles through the custom steering shaft above the driveshaft. There were two more versions: Michael M’s stretched one and LEGOTechnic360’s solid-chassis version with no suspension, but they didn't help me with any new ideas. Nothing personal, guys, if you're reading it, I just had a full and consistent vision of my further MOD: Hull - the original with no changes. Axles geometry - original. I tried to save the all things like the wheels location, suspension mounting points, ground clearance, steering angles (that are even bigger a bit now)… And I still can't believe that made it, after a thousand tries! Suspension - original, with no changes. However I put the hard shock absorbers in the rear end, as the default ones were too weak to keep the BuWizz battery. Wheels - original. I decided to keep the original wheels and tires with no giant crawler ones or even Claas, that are too big even for a Monster Truck. Frame - mostly original, but possibly modified since it will have an L-Motor and Servo mounted above the axles (right under the cargo platform and hood). Drivetrain - it must be the ex-steering shaft that comes through the cardans inside the "big" ball joints to the both axles, connected to the L-Motor via the set of normal and clutch gears. Steering - for the all wheels, like in the original model, but the steering shaft comes above the drive shaft, in parallel with it and can slide a bit while the suspension moves. Enough the words...The most interesting part starts here. Following my plan, the bigger challenge was to modify the original axles - I tried several options, even trial-like with solid axles, but 4WS provides an amazing maneuverability due to big steering angles, so axle diffs are likely vital for such model (solid axles were making a permanent clicking noise in the transmission even with motor stalling sometimes) and I decided to make a fast Monster truck, not a slow crawler with a high torque. The drive train. There you can see how I did it: L-Motor rotates a set of 8T and 16T normal and clutch (required for the steering shaft) gears and then the main horizontal shaft, that were used for steering in the original model. After that the shaft rotates the 12T double bevel gears (ex-pinon gears from the original model), than 20T gears below, single-bevel 20T and the differentials. As result, the gearing ratio is 1:1.667 X 1:1.4 = 1.2334, and provides about ~100 RPM with 15.12 N.cm torque. The wheels connected by a wheel hubs, since I wasn't able to use the universal and CV joints with affordable steering angles, wheels position (I kept exactly the same position as in 42005) and rigidness. The steering. Here you can see the servo (mounted upside down in order to provide more space for the battery block above, steering shaft that goes above the driveshaft, 12T gears (pinions) and 13L racks joined to the wheel hubs. In order to allow the suspension travel, the gears has 1/2L offset from the racks and slides together with the shafts along the mounting points when the suspension compresses. It's a fully legal, but still allowed in LDD and works like a charm! The only mistake that the hubs must be from Claas, but they aren't presented in LDD unfortunately: Just to explain why I used the clutch gears (but with no gearbox actually, ha-ha ), the drive and steering systems intersects so hard, so followed TLG way and used the same solution that they did in the official models (42029, for example) - passed the one through the other. Green is a drive subsystem, blue - steering. The Axles. Here you can see how the steering shaft slides by 0.5L (notice the gap between the 12T black gear and LBG liftarm) - it provides about 1L suspension travel for the both axles. Other images, the story of a modified hull (by Phil), LDD file and instruction in PDF are coming soon...
before i build my battlebot i decided to make a special project, namely: a 4ws supercar with suspension and drive to rear axles the steering works great Now uses gear rack in rear Servo rear geared down 300% Motors have a 3:1 gear ratio New version updated full gallery at http://bricksafe.com/pages/aventador2014/4ws# hope this will be usefull for all Aventador
Here's a Beach Buggy I made for an upcoming truck trial this weekend. This trial only has a few rules: Use 62.4 wheels, 2 motors for propulsion max and 1 for steering. It's based on Zblj's "Blue" suspension, drive and steering, modified to fit my beach buggy/trial needs. It features 4 wheel drive and steering. Was a little bit of work to work with the bright green from only 1 Le Mans set. Forgot to make a picture with the suspension pressed. Might make it tomorrow (bad lighting now). It looks pretty sweet with it compressed. The rear wheelarches look like they hug the wheels (a stud or so of space left between wheel and wheelarch). The car bottoms out with the suspension fully compressed. Here you can see how much I stole from Zblj. I only changed the type of suspension arms, slightly altered the steering mechanism and placed my motors differently for a lower look. (ignore my Lego tripod in the bottom right) Thank you for your time.
This will (hopefully) be my entry for the TC6 contest. Seeing all the great models already under construction (or almost finished), I don't see a lot of chances as a newbie, and I was thinking of withdrawing. So I thought it's a good idea to start a topic here and get me some peer pressure to finish ;-) As a big Citorën lover, the idea to build one of my favourite cars for this contest came quickly. But which vehicle would incorporate 4 independent PF functions? My choice was the Activa concept car from 1988: Shown at the 1988 Paris Motor Show, it showcased the electronically steered hydropneumatic suspension that was to show up the following year in the Citroën XM. Furthermore, it featured active anti-roll, four wheel drive and drive-by-wire four wheel steering with different modes, including crab steering. More info on http://www.citroenet...iva/activa.html The steering and suspension being the most interesting part for a Lego model, I chose the following 4 functions: _ driving (L-motor) _ front steering (servo) _ rear steering (servo) _ ride height (2 servos). I already finished the prototype of an axle (the two axles, having the same functionality, will be very similar; only difference will be that the front axle will include also the driving motor. Ride heights: The height adjustment mechanism was a bit of a challenge, as it has to move quite some weight on a small lever. It took me some time to brace the whole mechanism correctly. The next big challenge will now be to put the two axles in a strong enough chassis. The most difficult part however are the smooth, rounded lines of the Activa's body. I'm more at ease with mechanisms than with shapes, so let's see how I'll be doing... Comments and tips appreciated!