otpi

My humble opinion would be to add subforums only for very special subjects that can be strictly moderated, i.e. a forum for lego 3d drawing and creating instructions a forum for nxt programming maybe a review subforum (because it makes reviews easy to find) Other than that I believe a forum needs to have posts running off the first page to feel alive. General topics such as the "Lego Technic General one", and "Which set should i buy?" could get a sticky to keep them up top.

I solved this problem by buying more than one of each set. I keep one as display and the others as spare parts. My kids love to play with the display models, and if they break one I have good reason to rebuild it :)

Hm... I might have to blow the 2013 lego budget. I'd really like to have one of each, possibly two or three unimogs... I always watch for deals, but I may have to go for retail price this time.

Yes TRU. If it is an online offer only it will say so.

A fire engine with a working water hose! I can see that as a winner! yay!

4x 8070 Supercar, 2x 9398 4x4 Crawler, 2x 42009 Mobile Crane mkII, and 2x of those pullback models. If only I had more time... :)

Christmas came early this year. Just bought two 42009 mkII at a 30% discount. :)

Interesting... For some regions, e.g. Norway. You get "pick a brick" where you guys see "to buy a piece". If I select Uk or denmark, I get the same as in the post above.

That's a nice mod. Well done. I think the unimog wheels look good, but a tad off next to the 8070 front wheels? Maybe add some color to the all black canopy to accentuate the shape? Now I'm sounding overly critical.

Going thorough these steps I cannot find "To buy a piece"? I only get "pick a brick" where I cannot find the right panels and frames, or "my piece is missing", where I do find the desired pieces but I can only select as many as is present in the set I'm "missing pieces" for. Did they do away with the buy option?

I don't think the problem is the price, but whether there is actually a market for MOC plans? I'd happily pay 20€ for an awesome moc of respectable size, If I had a lot of spare parts lying around. What I mean is; since TLG don't have Technic part-packs readily available, most people only have bricks that are already tied up in models. So the thought goes: "Should I use my €, tear down a model, and build this MOC?", rather than: "I have all these bricks, what to do? Oh... what an awesome MOC! I'll buy!". That's, imo, why people are not willing to shell out the cash. As an example: Since I have kids, and like lego, I naturally told grandparents, uncles, and friends that where going to buy gifts to go for Duplo, specifically bricks (because you only need so many lions and police cars). We now have a "ton" of bricks (and eight lions and five police cars), sufficient to build a house of duplo big enough for one toddler to crawl into. That's pretty awesome. And every time we take out our Duplo we ask: "What should we build today?". If I could browse for awesome duplo builds, I'd probably pay... Only problem is that I would also be able to replicate whatever is shown from one picture, at least something that's close enough.

Your local RC stores spare parts section? It's not lego, but should offer tires that will fit your rims. Just bring one in and try them on.

Build your own diff using knob gears, a frame with the 40 t gear fixed. Takes up space, but should handle the torque.

Anyone tried chipping away the center ridge of the tires to increase grip? As it is the center forms a continuous slick surface. If I chip away 1-2 mm of the rubber between the tracks I believe the tires would grip edges a lot better. Thoughts?

Thanks. A good read. I have a pretty decent RC model car store nearby. I bet they have some of those wheels in stock, or something like it. Off topic; Anyone tried changing the lego battery for a RC 11.1 V LiPo battery. I know It's to much V, but I don't really mind burning a motor, and from what I have read so far it seems like the lego motors should handle it. Ideally I'd like to change the IR remote for my RF one, just to get the increased range and be able to use it on sunny days. Mybe this should be it's own topic. :p

It was also available at billund airport last time I passe through.

I support the parts pack idea. Looking at education.lego.com they already sort of have parts packs. It's just not widely/easily available. I find it strange that TLG forbids reselling parts from LUG orders. They are not supporting the secondary market anyway, so why stop those that do the cumbersome picking, packing and shipping of smaller orders. I think it hurts the techinc sales.

Even with the all the gearing on the input side of your linear actuators? Do you plan on implementing a system for crab steering? Won't the shorter track rod, that gives you ackermann geometry, get in the way of crab steering?

Yes, that's one of the compromises. You would have to return wheels to center and reverse the direction using gears to switch between modes. Just thinking out loud: For a 5 axle etf, do you think it is possible to turn the 4th using the angles of the 3rd and 5th, and some clever gearing to get 4th to turn. It should at least be possible to gear it such that the 4th gains 1/2 of the 5th and 3rd, i.e.: 5th at 0 deg, 3rd at 0 deg yield 4th at 0 deg 5th at 30 deg, 3rd at 0 deg yield 4th at 15 deg 5th at 30 deg, 3rd at 30 deg yield 4th at 30 deg For a 3 axle version you could do with one servo for aft axle pair, one for center pair, and one for the front pair. You would have to forgo the ackermann geometry for the left right side, unless you also implement track rod for fore and aft steering. But then you would not be able to turn the wheels 90 degrees? This way you wont have to switch modes mechanically, only on the nxt brick. Another way to arrange this is to have one servo for the center wheels, and connect left fore and aft to one servo, same for the right side. This require a gear switch to reverse the turning directions for crab mode. But you'd have correct steering geometry for all angles, but be limited to always turn about the center axle. Sorry for all the ramblings, I just thought it'd be interesting to see a solution that did not require eleventy nxt's.

It's a compromise I agree since even one nxt is expensive. A more expensive compromise would be to have two nxt bricks and 6 servos. three for the left and three for the right side of the vehicle. You'd have two steering modes: Crab steering which turns all wheels (turntables) the same angle; and regular steering which turns the front wheels opposite of the linked rear wheels, with the center axle fixed. Since the nxt servos measure angle you could maintain correct steering geometry over the entire range of angles. The down side is that you'd have to return to center to switch modes (which would reverse the turning direction of either the forward or aft wheels). You could do away with this in a 3 axle version, such as the one you have, since you'd have one servo for each pair of axels (front, center and rear). Come to think of it that may be preferable? Do you have one or two nxt's around?

No, no, what I meant was to link steering of 1st and 5th axles, 2nd and 4th, and center (3rd) by it self. This way you get away with 3 nxt servos and one brick. :)

Nice project! I had a look at http://www.etftrucks.eu/, that's some heavy machinery porn Would it not be easier to use a nxt and servos for steering? If you settle for the 5 axle variation you could use 1 servo for the first and last axle, one for the no. 2 and 3, and the last for the center axle. This way you could use the center axle as the fixed axle in for the ackermann geometry, unless you want to crab, then you'd turn all wheels 0-90 degrees depending on crab angle. Speaking of Matlab; If you need a hand shoot me a message.

Last year I caved in and bought my first two Technic sets in about a decade. The nxt and the 8043 excavator. Having kids is a great excuse (4yo is about the time one should start playing with nxt's, right?). Guess I'm back in the lego fun-zone. And Technic has come a long way since my days. I'd love to try my hands building a trail truck. Only one problem. I'm sorely lacking parts. So, 2012 went on without further lego adventures. Well back to the 8070; though I'd buy my brother an techninc car for his b-day. He has a kid of his own now, so he needs more toys. Though the accompanying choking hazard is probably his main concern right now... Anyway, it was his gift. Walking into the local toys'r'us I see the 8070 with a 40% discount. The discount put it at the same price as the "42006 Material Handler". What to do-- Obviously they had a whole pallet of them 8070 boxes left after what I assume was a botched Christmas sale, and since it's discontinued, they can't have them lying around. Being a nice person I should help So now I finally have lots of Technic pieces. Now I just need to get the crawler (or maybe two), and some xl motors, and... *hurr-thurr* And yes, Hi! /otpi addicted again

There are many ways to justify silly purchases :) , e.g.: - one is a gift - one is for me - one for the kid (ok, it's my lego, but he can play with it) - one for the good deal - I really need the parts. - It's less than a night out. - I wont get hung over from this. - The look on a kids face when he comes home to a stack of lego boxes this size - The very different look on your wifes face... Not the UK, further north and east. There sure is :) Yes lots of nice car parts. Which was of course part of my reason for buying, and that it was a good deal (it was actually cheaper than the cheapest used set on bricklink that same day). Thanks for all the welcomes ;)