Blakbird

Yep. The concept of having modular modules which can be interchanged is interesting, but none of the module combinations actually make any sense together. Every combination is an abomination.

Really? I love 8462! It is a very sturdy and playable model. I love the color, and the wheels are some of my favorite that LEGO has ever made. It is true that it doesn't look much like a real tow truck and no tow truck would ever use such wheels, but part of what I liked about it was the originality. It may not look like a real tow truck, but it does look cool. The Dune Buggy and Motorcycle with those wheels are great as well. On the other hand, 8244 is hideous in every way.

Fascinating! I never tried prying at this location because the slot behind the hub seemed so obviously to be designed for removing the part. The same reason you might take any other two pieces apart. Because they are LEGO. Just because a part may not have a bunch of obvious uses separately for MOCs doesn't mean some of us don't want to take apart the model and build it again. If it doesn't come apart, it is not as fun.

There are a whole series of older threads which debate the relative merits of these two systems endlessly. There are certainly trade-offs and reasons either might be chosen for any particular application. Personally, I dislike the label "linear actuator" and I'm not sure who started calling them that. Both systems use linear actuators. One is pneumatic and the other is mechanical, so "mechanical actuator" or "screw actuator" would be a much better name. The primary advantage of pneumatic actuators is that they much more closely represent the real workings of hydraulic systems in heavy equipment. For this reason, pneumatics tend to be preferred by builders who are going for maximum accuracy. A second advantage of pneumatics is that it is very easy to locate an actuator at a great distance from a power source with minimal loss of power. The primary advantage of mechanical actuators is that they can be accurately positioned and will retain that position under load and over time. There is no general rule that will tell you which kind are capable of producing "more power". It totally depends on the pressure, the size, and the efficiency of the system. In LEGO, the load capability of a pneumatic actuator is limited by the pressure at which the internal seal begins to leak or the tubing pops off. This tends to be about 4 bar. The load capability of the mechanical actuator is limited by the internal clutch. Not surprisingly, LEGO designed them to be pretty close. I design and analyze both hydraulic and mechanical actuators in real life, and both have their advantages. Heavy equipment is almost entirely hydraulic, whereas mechanical actuators are more likely in robotics or precision equipment.

I once contacted LEGO to see if I could obtain this kind of information as an addition to Technicopedia. I was told that it was not LEGO policy to give out such information. In recent years, due the LEGO Technic web site we actually know who is on the Technic design team and often know who designed specific models, but this information was not available in the past and it does not appear that LEGO has any intention of releasing such information. There may be some cases in which there is an interview or magazine article which will give you design info on a specific model, but in general it seems that this will remain a mystery of history.

Here's where we have a difference between force and displacement because the fluid is compressible. For a given pressure, a pneumatic cylinder of any length can lift the same weight. However, a longer cylinder will require more volume of air to lift that weight over a longer distance. So working backwards, if we place a fixed weight on both a long cylinder and a short cylinder, the long one will compress further before it equalizes the pressure. From that point of view, longer cylinders would be "squishier" due to the larger compliant volume. This would not be true of hydraulics.

I've had the same problem. I completely destroyed a set of my portal axles trying to get them apart with a pair of flat screwdrivers. Now we've seen that there is a way, but it comes with a huge safety warning. What's going on here? This is not very "LEGO like" to require a dangerous procedure to get pieces apart. I would just say that they are designed to never be disassembled, but the presence of a slot on the side clearly indicates that they ARE meant to be disassembled. So why is it so hard? There's no way a child could do this safely. I'm not going to make any further attempts to disassemble mine. I guess they are together forever.

8258 has only one differential and it is between the wheels on the 3rd axle. 8110 has 3 differentials, front, rear, and center. Apart from this simple differentiator, there is no way to choose between these two models. Both are fantastically fun and well built. You are going to have to get both.

Nice! Kind of like an updated 8868. This is the first time we've seen a mini and a regular linear actuator in the same set. The log is a lot bigger than those in 8069. First order of business, dual tyres on the rear axles!

As a set, it is not fantastic. However, as the historical reintroduction of pneumatics after a long haitus, it is hugely important. At the time it came out, it was very worth buying because it was the only way to get new pneumatics. It was also only the second set ever with a (optional) compressor. The fact that they included the compressor pump part even though it wasn't used in the model unless you motorized it was very generous.

My point is that real R/C vehicles that hover (like helicopters) have adjustable throttle, adjustable pitch on the rotors, gyros, and many other electronics to keep them stable. Even so, the very best such vehicles I have ever seen (which cost many thousands of dollars) are nowhere near as stable in hover as this thing is. So either this is the best vertical flight vehicle ever made (impossible with no gyro or swashplate) or it is actually not being supported by the lifting surfaces. This looks to me like a "control line" model, which is quite common. Weight is carried by a string, and the motors only provide propulsion.

Hmmm, I'm afraid I don't believe it. The weight is clearly being supported by a string. The rotors are only providing thrust. This thing has no control surfaces and therefore could not possibly hover without external support no matter how much thrust it has.

OK, that makes more sense. A brushed ESC modulates the speed of a DC motor by simply varying the voltage. As long as you are using a 9V battery to power your ESC, and as long as you are using a reversible ESC (usually from a car, not an airplane), this should work just fine with Mindstorms motors. Just make sure you tap into the positive and negative wires of the motor. If you actually wanted to measure rotation like a servo, that would be a lot more complicated. You can get ESC's in almost any size; they don't have to be large. I'd recommend a 10 Amp ESC for use with LEGO motors.

If so, then everything is fine. I suppose we should not jump to conclusions.

The problem is not so much that they are selling a kit of parts, but that they are also selling Skyliner's instructions with it. The instructions are copyright and owned by Skyliner, so the sale is blatantly illegal.

As someone who has built this car I can confirm that it really is an excellent and strikingly beautiful model. It fit in easily with the best of the models on the supercar table (there were 11 in attendance). Thanks again to Jurgen for designing it and sharing the instructions with the world. To those waiting to build it, you will be happy to know that no #4 yellow angle connectors are required. Good luck with the 19L black flex axle though......

The suspension needs to work under a variety of loads. I think the stiffness is not bad when there are no accessories on, but it gets pretty soft when you have the crane and plow both installed. Personally, I find most LEGO suspensions too stiff so I'm happy to have a softer one. For the pneumatics, you are finding the result of a lack of pressure relief valve in the system. With nowhere for the air pressure to go, the system just keeps building pressure until something gives. The first thing you notice is that the system slows down as the back pressure builds up and makes the compressor more difficult to turn. Then the piston seal inside the compressor starts experiencing blow-by "leaking" which is the sound you are hearing. Without that seal leakage, you'd build pressure until something blew up. There's really no way around this with LEGO pneumatics since there is no relief valve. The only alternative is to build a regulator by using a spring restrained cylinder to turn off the power via a pole reverser when the pressure is high enough. That's a pricey and spacious solution that LEGO has never used in a real set though. I'm just glad we got a compressor at all.

I admire your determination! I fly a lot of R/C helicopters and airplanes, and I also analyze real airplanes for a living. There is a very obvious theme here and that's the importance of minimal weight. Lego structures made from ABS and snapped together with no mechanical fasteners have a lot of disadvantages when it comes to achieving flight. However, when someone challenges me with a question like "is it possible?", the answer is always "yes". The caveat is, "how hard are you willing to try?". After 10 years flying R/C, I've stated that I can make any object fly with enough power. So you could indeed (for instance) build a LEGO Technic airplane fuselage, wings, and even flight control surfaces. You'd have to cover them so seal the openings. It would be really heavy, so you'd have to add an obscene power system and you'd have to use proportional servos. Take off and landing speeds would be very high. But it could be done! Dluders has flown a LEGO rocket. Again, with enough power you can launch anything. Helicopters get a lot harder though. The rotor and swashplate system can be simulated with Technic, but they just don't have the tolerances or torsional rigidity to support the required loads to generate critical lift. So what about if you used a commercial helicopter rotor system and made the body of LEGO? Maybe, but those rotor systems are made only to lift bodies with weights proportional to the rotor size, so the assumed weight is much lower than you could achieve with Technic. You could theoretically use a rotor head that is way too big in scale with the body. Helicopters also have a lot of vibration and require rigidity as well as light weight. I'm fairly confident that, with enough budget, I could make a flying helicopter with a LEGO body. It would not be a very good helicopter, but it would "fly", more or less. I stand by my original statement that making an entirely LEGO (heavier than air) creation fly is probably impossible.

Short answer: no way. Lego parts do not have an airfoil shape to make a proper rotor for lift, and they are not even flat plates. Even with a proper airfoil shape, you could never get enough torque through an axle to lift the weight of a LEGO helicopter. The best you can hope for is a mild breeze generator.

You need to be a lot more specific. What do you want to attach to a LEGO model? An R/C vehicle has a battery pack, a speed controller, a radio receiver, some servos, and a motor. Which of these things do you want to use with LEGO? In any case, there is always a way. It depends on how hard you want to work. The guys over at Inanimate Reason do some of this kind of stuff like attaching R/C servos and wheels to Technic.

Must be different in Norway then. In the US, every tow truck I have ever seen has tandem rear wheels. It needs the extra rear load carrying capability to lift a vehicle. Note that I do NOT mean two axles, I mean 4 wheels on one axle.

Yep, it's ugly. The preliminary art is "boxy" though so it will look better later. I think tandem rear wheels would make it look much better.

Thanks for the link. I did not realize that SR3D had its own forum. It is one of those tools that is obviously perfect for Technic, yet I have so far been too lazy to learn it because I have already invested so much time in learning MLCAD. I think the other reason I have not tried it is that once I do I will want to go back and make all new animations for Technicopedia with it and that will take me forever. 8070 worked though!

I don't seem to be able to download this file. I get an error (which I can't translate). Looks like a great model though! I'd be interested in rendering some of your newer model CAD files. I can make the flexible parts for you.