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That's not a bumper. Those are front weights. ( you can hang weights in front of a tractor to balance the weight, you can find some pictures on: http://www.everythingattachments.com/tractor-weights-s/8408.htm ) Great review, this looks like a really nice tractor.

Your video shows a clear difference. How long do the AA batteries deliver enough voltage to run faster than the rechargeable ones? An alkaline battery starts out at about 1.6 volts (with no load) which drops to about 1.5 volt under a modest load. Its voltage gradually drops from there to about 1.0 volt, at which point it is empty. So while a brandnew battery produces more than 1.5 volt, the average voltage over its lifetime is well below 1.5 volt. The rechargeable one drops from about 1.4 volt (fully charged) to 1.2 volt. On average, it produces 1.3 volt (which is more than the nominal voltage) and it does not drop as much under a load. In any case, the initial difference in voltage is less than 25%, and only decreases from there on (if both batteries are half-empty, they'll produce roughly the same voltage, when both are almost empty, the rechargeable one produces more). So the difference in speed is quite surprising, nevertheless, the video demonstrates it very clearly. (PS. The 7.4 volt lego rechargeable battery, when fully charged its output is more than 8 volts).

How old are the rechargeable batteries you're using? Is there perhaps a bad battery in that badge? My impression with 8043 was that with new rechargeable batteries, under a high load, it performs better with rechargeable batteries than with alkaline batteries (despite the lower nominal voltage).

My preference for an ideal technic set would be a set that comes with a huge number of models, especially when the models are quite different from each other (just like the set 10183 in the train theme, which has 30 AFOL-designed models).

After you have had one of these wonderful models for some time, perhaps you could disassemble it and sell it (or exchange it for another model) to someone else on eurobricks?

Looks great, with the battery box well hidden (make sure to put in fully charged batteries, taking them out to recharge them will be some work...). Thanks for making instructions available, really appreciate it, I love seeing the design.

Pneumatic is more realistic, but is not 100% realistic because it uses air, which is a lot more compressable than the oil used in true pneumatics. And you definitely notice this. Even so, 8868 is awesome. However, 8043 is even more awesome, and remote control works better and more precise with linear actuators than with pneumatics (to pick up a pencil with 8868 requires a good bit of practice, 8043 is much easier to operate).

Has anyone tested an actuator with an L motor? Does that produce enough torque to make the internal clutch start to slip?

I may be wrong, but at 12 volt it seems to go only a little bit faster than at 10 volt (still fast enough to fly out of a curve though!). That makes me wonder what it'll do at 20+ volt (I don't want to test mine at 20 volt, so I can't be sure if it'll do well or not).

Perhaps the carbon in the commutator (see: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/comtat.html ) makes a better electrical contact when it is warmer. Once the carbon on the commutator is worn away, then the motor is dead (it may still spin, but it'll spin irregularly). This is what happened with my two burned out 9V motors (I checked this, I opened up the 9V train motor, applied electricity to the DC motor inside. This DC motor has, on one side, a white plastic cover, and you can see it light up when you apply electricity to the motor. The light comes from the sparks from the commutator. But only a worn-out commutator sparks, so that's how I know that a worn-out commutator is the reason that my motor is no longer functioning properly). A high sustained current can heat up the carbon (9V on a stalled motor is more dangerous than 18V on a spinning motor, because a stalled motor draws much more current. To be more precise: the current is roughly proportional to the torque). You want to build the trains light-weight, that means less torque is needed from the motor, which means less current, which in turn is safer for the carbon in the commutator. If the current is very high, the carbon in the commutator can evaporate quickly (it turns to CO-2, so you won't find a black residue inside the motor). Once the carbon is gone, the motor is dead. In the 12V train motors, if you open them, you can see the commutators. Those motors are built rather sturdy (if you buy a used 12V motor that does not run properly, in most (not all) cases it'll run as new after you lubricate it). But they're not so useful for you because although they are tough and can survive quite a bit of abuse, they're not the best for high speeds. 9V motors are much less sturdy, I think that lego was trying to save some money here, and that they were assuming that the load would be light. The PF motor has to run on AAA batteries (while the RC train runs on AA batteries). To get a good battery life with smaller batteries, lego had to use a more efficient DC motor than what they had in the RC train. I think that a more efficient DC motor will likely be better in all aspects, so I suspect that the PF motor can survive more current. If my reasoning is correct, then users of PF train motors will see few burned out motors. I have one other question for you (this is related to track conductivity): do the motors on the outside of the train get warmer than the ones in the middle? On eBay, I've seen motors that look the same as the ones inside the 9V train motor, but I have not tested yet to see which one would fit. Soon after I started buying 9V, I burned out two 9V motors. So what I did was: a) Search for how to fix them with replacement DC motors b) Bought a good number of spare motors (these have since then doubled in value on bricklink) c) I've kept a very close watch on what the motors are doing: I measured in each train how much current the motor uses (and use this data to decide if 1 or 2 motors are needed). And I made sure their load was reduced as much as possible by reducing the friction in the wheelsets. But by being more careful, I have since then broken no more motors. Since I only have 2 motors that need repair, and since I have many spares, there was no need to fix them yet. But it should be possible to buy DC motors that fit (after all, lego must have bought them from somewhere too) and I have seen motors on eBay that appear to be very close in size.

I thought of a different way to save a substantial amount of money. Take a burned out 9V train motor, remove the internal DC motor and other unnecessary things, and whats left, use that to pick up electricity from the track. Then, put only PF train motors (from the new train sets, not the RC motor from the 7897 set) in your train, and put wiring in the train to get the electricity from the emptied-out 9V motor to all the PF train motors. This saves money in two ways: The PF motor can be bought new from lego.com (again, buy only the new motor, don't buy the one from the 7897 set even though it is on sale). It is much cheaper than a 9V motor. But I think you'll save money in another way too: I think that the DC motor inside the new PF train motors is more robust (will handle the abuse better) than the DC motor in the 9V train motor. I think these motors will last a lot longer than the 9V train motors. On the topic of trains with multiple 9V motors; I've had a bad experience with that once. I had a heavy cargo train with two 9V motors (both old ones). One of the motors died; this put a lot more stress on the other motor (not only did it have to pull the train by itself now, it also had to pull the dead motor) and as a result, 1 dead motor became 2 dead motors. Since then, if a train has more than 1 motor, I watch it carefully for signs that this may be happening (if the train gets a bit slower on the same voltage for instance). Given a heavy load, I'd feel more comfortable with PF motors than I would with 9V motors, I think they're more robust (don't know that 100% certain; of course, if you try, you'll know soon enough, few people put as much stress on the motors as you do!)

I think that the 600mA (on one motor) is about a factor 2 higher than the actual value, and the resistance of the track you mentioned is about a factor 2 lower than the actual value; this cancels out, meaning that the voltage drop you calculated is correct. The stalled current listed on the motors website occurs only if you hold the wheels completely still, and put a full 9V on it (to do this experiment you need a different power supply, the standard 9V controller can't produce the amps needed to get to 9V in this experiment).

This set looks wonderful if you have the BNSF locomotive (you can see one in ),but as you mentioned, you can't combine this with Maersk because its not the same scale.

4511 is an excellent choice for high speed because its light weight. Do you also make cuts to the wheelsets to make them run smoother? (described in railbricks #2 page 49). That lightens the load on the motor, which could, at the high speeds you're using, make a big difference in the motors life-span. Rapid acceleration is necessary to reach a high speed, but this is of course the part of the track when the motors wear the fastest because that's when they use the most current. Would it be possible to have a siding somewhere in the track, where you keep alternating (run one train, then the other, then the first one again, etc.) so that the motors have more time to cool down? Also, I'm wondering if it may be helpful to drill a few holes through the plastic cover, so that air moves through when you're running the train. Anything you can do to lower the temperature will save you money; these 9V motors are expensive, and fairly fragile. By the way, don't throw out burned 9V train motors; they can be repaired at a cost that is much less than a new lego 9V motor (open them up, and buy a non-lego DC motor (you want one that has an axle coming out on both sides). They pry the gears of the original motor (it's not too hard to get them off) and slide them on the non-lego DC motor.

It'll probably make the Emerald Night go quite a bit faster. But I heard it'll be until March that one can buy them separately.

Fantastic layout, very beautiful. How long do your motors last?

There is one concern I have about this change. Having an L motor for bending the arm will increase the strength in digging, however, that would also put more torque on the universal joints in the arm. I remember reading somewhere that an XL motor can break universal joints (of course, the L motor does not generate as much torque as an XL motor, but it does produce a lot more than the M motor). What I'm wondering is if the universal joints can handle the torque produced by an L motor.

Has anyone tested if the new L motors are easy to fit into 8043? (it'd be nice to replace motors #1 and #2, that operate the arm and the two tracks).

Under a high load, rechargeable batteries last a lot longer than regular alkaline batteries. Alkaline batteries give a higher voltage (nominal voltage is 1.5 V per battery). But they only produce that voltage when (a) the load is light (say 100 mAmp) and (b) the battery is full. But 8043 will easily draw more than 500 mAmp, and under such a load, two things happen: (a) alkalines AA's under this load will deliver a much lower voltage than their nominal voltage (in fact, they'll deliver less than rechargeables) (b) alkalines run empty much faster than the energy content written on the battery. With rechargeable batteries, you can run the 8043 non-stop for many hours, and it'll stay strong until the batteries are nearly empty. With alkalines, you'll get that performance for only a very short time, as soon as the alkalines are not completely full anymore, the rechargeable batteries will outperform them. So basically, you should use alkalines only for low-load applications (e.g. in the remote control they are fine), and use rechargeables for all high-drain applications (such as: your photo camera, your 8043, etc). http://site.greenbatteries.com/documents/alkaline-vs-nimh.jpg In principle, the new v2 ir receivers should be better, but I suspect that the difference will be small (has anyone been able to notice a difference?)

I would vote for 853 but not because if its main model; on the box there was a picture of a very nice jeep but there were no instructions for it. That meant many hours of puzzling/building/changing/etc. but after that, I wondered that if 1 drawing was enough to build a model, then 0 drawings should also be enough.

Yesterday I put some new AA rechargeable batteries (fully charged) in 8043, these batteries are more powerful than what I've used before. With both friction pins removed in my 8043, it function-switches so fast on those new batteries that when I switch to arm-operations, it occasionally bounces back to neutral (if I only touch the red control on the remote controller for a very short time then it works OK). It seems then that, if your batteries are very strong, then some amount of friction is helpful to prevent bounce-back. Perhaps using 1 friction pin instead of 2 would have been optimal.

L motor: about the same speed as the M motor, but much more torque XL motor: turns slower, but has much more torque still For a more precise answer, see: http://www.philohome.com/motors/motorcomp.htm

650 mA will kill the motor quite quickly! A more typical load is 200 - 250 mA. My Maersk train ( ) is about 10 feet long,has two 9V motors. The two motors combined draw 420 mA (in the video, it is at speed setting #2 which means 4.2 volt, but there is one corner where it slows down; one more wire needs to be added there) (the current 420 mA stays almost the same regardless of speed setting). At speed setting #3 (5.4 volt) it runs faster than I want (I want my cargo trains to go slow) so I have to go with #2 (4.2 volt). But at about 3.2 volt it runs slower than I want. So the voltage drop must be less than 1 volt, which, at 0.420 amp, corresponds to only a few ohms, meaning that quite a few wires are needed for this loop (I'm using 4 wires, and get practically a constant speed on the loop except in 1 corner; one more wire is needed).

I like my passenger trains to be around 5-6 cars long, between 4 and 5 feet long. My favorite is 4511. They sold separate cars (10157 and 10158) so you could make the train any length you want. The cars from 4511 are quite light weight, my train is 6-car (5 feet long) and still only needs one 9V motor. Two sets of 7897 (at the time, 7897 costed $89) combine also to make a nice 5-car train (I replaced the motor that came with that set by a newer motor 88002, that motor is stronger). I bought one set new, and another set used (when 7897 was still for sale at lego, a used set on eBay costed only $60). You can do the same with 7938 but that set has a substantially higher price tag than 7897, its not cheap to get two of them. The metroliner is also very nice. If you spend some time looking for deals on eBay, you can buy it for less than 7938, and it is certainly nicer. But when it comes to cost, nothing trumps the 7740. To get a 7740 train of the desired length, I had to buy two copies. That was a lot of money.

I have lubricated a few things, but I worry about putting lubrication on axles because if you re-use the axle for something else, then the things you put on that axle might slide off too easily. Has anyone had that problem, or is that not something to worry about? (can I wash off the lubrication to prevent this problem?) I don't see much of a problem with putting lubrication on the teeth of gears, because nothing has to stick to that. To those who say that they never take apart any lego models, quite frankly, I don't get that. The beauty of lego is that with the same pieces, you can make different things. I think it's pretty neat to take apart 8043 B and then build 8043 A.