TJoling

I agree with krisandkris12, as soon as you go larger than the standard technic scale, the forces become soon to large for normal compact constructions to work properly. The reinforcement which are then needed are very quickly causing problems in terms of available space. On that note I'm very curious to the progress of this project. I will follow this thread closely.

Although it's a Work In Progress for over 3 years already, it will be finished some day, so lets make a topic about it. I've been working on a unimog wheel based four axle mobile telescopic crane, the Liebherr LTM1100. The undercarriage is already standing around in semi finished condition for quite some while, waiting till I got inspired again. And while I was tearing down the 42009 I got my inspiration back! Since then I started building the superstructure and crane boom. Because of the scale I was able to make a four stage telescopic boom without making one or more of the sections look out of proportion. This posed a nice challenge, and I think I tackled it by now. At full extension, the boom now reaches to about 2,5 meters. In the pictures, the top part reaches past the ceiling actually. Boom by Thomas Joling, on Flickr Boom by Thomas Joling, on Flickr And a video I made this morning, testing if the mechanics for lifting the actual boom were up to the task: As you can hear, they are not, but we'll fix that :D For other pictures, head to the flickr album If you have any questions, put them below :)

Well, it's an educated guess, based on holding the boom with a stretched arm. I could be off by about 100 grams :P I built a new internal frame after shooting this clip, which now connects the cylinder and winch, making the structure much stiffer, reducing friction in the winch gearbox by a great deal. The XL is now capable of raising the boom on just speed 1 of 7 of the PF batterybox! To be honest, I had lubricated the piston as well on that attempt. It also takes a lot of parts; I've destroyed parts beyond recognition in ways I didn't suppose to be possible before destroying other parts first.

3 months later... The raising of the boom is functional! Complete with all 3 three of the extensions it can now be raised by a single XL-motor: The noise is caused by friction of the rope, not gear skipping. Next step: motorize the hoist winch.

Time for another update. Last weekend I brought the beast to a local AFOL meeting where this photo was taken by Barman: The cab is rebuilt in the meantime, so it starts to look like the real thing now. Also, the winch systems in the superstructure have been fitted and re-fitted to accomodate the immense forces exerted on the parts. At this moment, the winch for extending the boom is functional. It is powered by a L-motor and a 1:24 geardown. Only the last section has to be extended manually, but it will probably be rebuild so it will be extended automatically with the other parts. The winch for raising the boom has been overhauled completely. At first, the geardown for the winch was only on the outside of the frame, which resulted in the twisting of a 5 studs long section of an 16L axle The winch is now first geared down 1:5 before the axle is led to the outside of the frame where further geardown will be built. Hopefully this will make the winch a little more reliable. Small problem is now fitting the XL-motor to the outside of the frame, since there's only 5,5 studs left to put it, otherwise it would stick out to the side. After that's done, and I found a sollution to drive the hoist winch without any gears or axles sticking out of the body, it's down to the undercarriage to try to make the steering system work, and to see if the beast will actually move by itself. Hopefully we've conquered the biggest hurdles by then. But that's a long way away for now

I might do that if the friction turns out to be too much, but i'm not afraid of that since the turntable isn't a loadbearing piece between the undercarriage and superstructure Sounds interesting! I'm curious how you are getting allong

Thanks kisper! The weight of the boom all in all is about 700 grams I guess. It's quite a heavy piece of kit.

The progress of the last weeks. The superstructure received a new brick built frame, which is more rigid and less bulky than the studless frame it had. The turntable has also been changed, the actual turntable is turned upside-down so the superstructure can not detach from the undercarriage. Now tiles are used as bearings, so I hope this won't have to much friction, otherwise I have to put rollers under the superstructure. Up until now everything is smooth sailing though. Next up, getting the undercarriage to steer as it is supposed to do.

Hi all, When I'm designing the exterior of the vehicles I build, especially when it's a scale model of a real life vehicle, I tend to draw the contours on a piece of paper and put a grid over it see how every detail should be positioned. Although there are a lot of fancy computerprograms like photoshop which can do this for you digitally, I tend to do it on good ol' paper And I figured I may not be the only one who thinks photoshop is too complicated to do such a simple task, so I made a couple of pdfs and put them in a shared folder for you to enjoy too link In the folder you will find 4 files: a grid the size of 1x1 plates and a grid the size of 1x1 studs, both available in A4 and A3 printsize. Good luck with them!

This is looking all very realistic, considering the scale and the fact it's all functional. I like it very much, bravo!

I'm afraid the pictures of the undercarrier aren't very representitive for the end result with regard to the technical solutions. I've discarded the idea of the gearbox as it doesn't much to the model, because only the third axle is going to be driven, so I'll apply only the minimum required torque to the wheels in order to keep all the parts intact. More torque provided by a gearbox would only break parts, which isn't my intention :P Also the clip showing the steering system is actually out of date; the system had to much play, wasn't strong enough and had too limited possibilities. It was actually based of an adder-subtractor system, but instead of a driven left and right track, the front two and rear two axles were steered. I am now aiming for the four different steering modes too. So a whole new carrier is being designed, at least technically. Still no suspension though, because I think the added play in the axles will harm the drivability when it's finished, especially because of the huge weight in the end. Also, the chassis will now be stiffer and I have a lot more space to accomodate the steering system. And again, it wouldn't add much IMHO since trial-like activities are alredy out of the question ;) You're right about the width of the boom, but I think only people familiar with the matter will notice that. Besides it's a technic model, so added technicallity of the four stage boom is prior to the aestetics :P The telescoping is really smooth, except for the last stage. I have yet to motorise it though. Just as the boom raising cilinder it is going to be rope driven. The rope inside the cilinder is running up and down 2 times, giving a mechanical advantage of 4 so it is very strong indeed. The skipping in the transmission of the winch is probably caused by the actual warp of the winchaxle, because the rope more or less pulls the winchdrum away from the gears driving it. The winchdrum is now geared 12:36 and 12:20, but I'll probably change that to 12:36 and 12:36, accomodating the added weight of the telescopic stages which were left out in the video.

I think you need this: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=545789

They obviously use 7 wheels on the tractor (2 front axle, 4 rear axle and a spare) which leaves 4 wheels for the trailer's axles and a spare on the headboard.

Misha van Beek: http://www.brickshelf.com/cgi-bin/gallery.cgi?m=miezel

I know for a fact that the first part of the ID is the identificationnumber of the mold used, which explains why elements can have several ID's. A 3 figure section is reserved for the color of the part as well I believe.

What a great model! It functions really well, especially considering its humongeous size! The looks are also really good. This is a moc to be proud of! I'm really curious why you need the intricate dual valve, servo system for the rear axle steering. Could you elaborate that please? Maybe with a picture from the underside of the rear axle?

Don't you get a lot of additional friction since the servo cannot go to its final position and keeps on pushing the changeover catch into the driving ring?

The range of movement is appaling indeed! But that can easily be fixed by changing the pivotpoint on the lever which connects the LA to the bucket, right? You lose a bit of force for tilting the bucket, but the range of movement increases a great deal. I do not own the set, so I don't know if this is possible, but that would be my solution.

Hi all, Here's the first moc from my side to present here. As the title says, it's a Trophy Truck, which is a known phenomena by now I guess, seeing all the technic trophy trucks appearing lately Mine however, is supposed to be a little different from the rest, since I like a small technical challenge. I let the pictures speak for themselves first: Trophy truck WIP by Thomas Joling, on Flickr The first mock-up with the initial design ideas visible: pneumatic suspension, 5 RC motors for propulsion. Proportions were out of sinc though; Trophy truck WIP 2 by Thomas Joling, on Flickr Pneumatic suspension discarded to be added again later on. Fixed the proportion issue by shortening the middle part. The front RC unit is now to high up and to much upfront to be properly hidden by any bodywork. The steeringoutput of the unit couldn't be connected to the gearrack either, so a servo had to be put underneath the unit, raising it even more. As it turned out later on, the RC units output wouldn't have been powerfull enough to make the thing steer anyway, due to the combination of the large caster angle on the front wheels and the weight of the unit itself. The large caster angle is achieved by tilting the whole suspension backwards. This was also the reason why the steeringoutput of the rc unit couldn't be connected to the steeringgear. Anxious to try if 2 rc units pack enough punch to power 5 rc motors together, I let the aesthetic issue of the front rc unit for what it was, figuring I could solve that later, and put the thing on the street. Turns out rc units are designed to power 2 rc motors, THAT'S It. The 5 motors caused some unexplainable behaviour from the rc units (sometimes it seemed like one of the units couldn't make up its mind whether it should drive forwards or backwards, regardless of me giving the signal to drive forwards ). This stuttering has caused some broken U-joints in the meantime. This made me try out different driveshaft designs, including springs to keep the darn thing in place; no success either Eventually I found that 2 POOP U-joints together with an extendible axle made of a portal axle hub and wedged belt wheels worked the best without having to use non-lego parts. Now I could definitely see 5 rc motors were really to much for the rc units; the thing could bearly start up without the power shutting down, and once rolling it could only just surpass normal walking pace (instead of ). I decided it would be best to remove 1 rc motor. This would improve reliability, (hopefully) performance and because I could build the middle part more compact, it would improve the aesthetics as well; the front rc unit could be moved backwards and lower down. I put on some unimog tires on 41999 rims for that actual trophy truck feel I turned the units and battery on, put the truck on the ground and slowly moved the joystick forward, and.... nothing! Apparently I already drained two sets of batteries while testing before (i bought them new) so I now have to buy new batteries before continuing.When I've done that, the story will continue

That's a good point. I hope to keep the weight below 2 kg actually. Thanks! The rear suspension holds up pretty well, I only had to make some reinforcements on the dampermounts to the trailing arms. I'd like to see what you would make out of 4 rc motors in a trophy truck! I experienced the same at first, so I made a different design of U-joint which you can see on the last picture (bearly). These are a lot stronger, and don't suffer from torque twisting.

The original idea actually was to put springs along a central pneumatic cilinder, which would keep the whole system under vacuum. The principle should work, although in practice it requires some more finetuning unfortunately. I probably should switch to first gen pneumatic components... @lukeandahalf: Thankfully I got a 8366 as a birthday present when they were still on sale. Lucky me found another one on Ebay a while back for about €30. The seller rendered it worthless since the remote didn't work anymore, and the set itself missed some parts and the booklet. The important bits still worked like a charm though

Thank you, I've been working on it for quite a while now, but the end isn't anything near in sight Luckily, I have the original middlesection with the adder-subtractor assembly still in one piece. I will try to make some detailed pictures of it when I'm home this weekend. To answer your first question: I said the axles approach the right angle in either one of the modes The ratio between the axles is 6:7, so pretty close to 1. This means the axles don't have the right angle in normal steering, or in crabsteering, but both ways the angles are pretty close. The slack between the gearrack and wheels, together with the all wheel drive, will give the wheels enough play to reach the optimum angle on their own. In theory, it's more like crapsteering , but in practice it works pretty fine. Your mock-up could indeed be improved in terms of slack, but I still think the biggest causes of slack are the diffs, which can not be discarded in your design. I would still like to see an improved version though

What's holding you back building one yourself?

I did notice the change in steeringangles between the modes in your system. However, to achieve that you have to make the system a lot bigger, and the slack will even further increase as you're using a lot more gears. I tried to solve said problem by putting a 12z gear on the gearrack of the first axle seen from the middle, and a 14z gear on the gearrack of the second axle seen from the middle. This reduced the slack between the axles in a pair to a minimum, and made the axles approach the right angle in either mode. I think that it depends on the size and weight of the vehicle what would be the best solution in this case.

I've been tinkering with this idea before too. I built an adder-subtractor construction inbetween the axles, and used both outputs to steer the front and the rear axles separately. In essence it's the same system you built, only now you save yourself two diffs. But again, as said before, I also discarded the idea due to slack in the system and having to perfectly align into the straight position before switching to the other mode. I made a small demo back then. I have also been thinking about the ackermann in normal steering and non ackermann in crabsteering and how to solve that. at some point, Barman came up with a great idea: But to mechanically control this is terribly complicated, you're almost forced to use mindstorms.