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Rather than using a guiding, you can have a diamond shaped linkage to provide lateral support with minimal friction o /|\ / | \ / - \ o | | o \ | | / \| |/ \-/ o But yes, you could not completely eliminate this. I would probably also set it up to lift a weight via a couple of pulley wheels. But yes, I agree that this kind of test would be less precise than your motor tests. I do, however, I think the qualitative results would still be of interest - it could also help to provide guidelines on when it is advantageous to use two coupled LAs, etc. OK, so I'll do some experiments soon

that's the one

It wasn't that - it's just that you don't want to join them with a diff

If you're going to do that, use diodes (0.7V drop per diode), not resistors

Thanks for another addition to a great resource. If you were interested in doing some more experiments (seeing as you look pretty well setup there!), one I'd be really interested to see is a characterisation of linear actuator efficiency under different loads. Especially comparing the difference between the new (8043) ones and the old ones. I guess the experiment would go something like this: Create a profile of torque vs. angular velocity for e.g. an M-motor (you already have this on your page), but it might need to be remeasured for the motor being used. Configure a motor and linear actuator so that the linear actuator is lifting a constant mass (it would be interesting to compare the upward and downward performance too) Measure the angular velocity of the motor. (or the speed of the actuator shaft) From this angular velocity you can work out the input mechanical power (using the profile to estimate the torque on the motor), the output mechanical power, and hence the efficiency Change the mass lifted by the actuator, and repeat I want to do this experiment myself, but I don't currently have a bench power supply, or a particularly easy way to measure angular velocity.If you, or anyone else, feels like performing this experiment, I'd be pretty interested in seeing the results. If not, I'll eventually get around to doing it myself!

Agree, and a video would be even better if you could

I don't think that works -- or maybe I'm misunderstanding what you're suggesting. If you connect 1/15 and 1/2 by a diff you get (1/15 + 1/2)/2 = 17/60. Conversely, if you connect 15 and 2 by a diff you get (15 + 2)/2 = 8.5 Sort of - using differentials lets you add, whereas regular gearing up and down only lets you multiply -- the output of a diff with inputs A and B is (A + B)/2. You can also subtract by negating (reversing direction) of one of the inputs, or by treating the differential casing as one of the inputs. This means with a bit of thought you can get any gear ratio you want, including ones that don't have 2,3,5 as prime factors.

Does everything spin freely when you disconnect the motor?

Wow! What a stunning model I've been thinking that mounting a camera on one of these -- as is for panning, and with a different gear ratio on top for orbiting would be a way of easily achieving some interesting camera motion. Like Blakbird, I'd be interested to hear how you achieved it. If I find a bit of time in the next week I might try and create a demo to see how well it works. http://www.youtube.c...h?v=HE1N58tvg5Y

I've been building a few stock sets up recently and, in a way that I haven't really been conscious of before, I'm appreciating the different styles and personalities of the designers that created them. Recently I've rebuilt 8292 (Nathaniel Kuipers), 8295 (Alfred Pedersen), and 8043 (Anders Gaasedal). Putting aside questions of how good the finished products are, they really are completely different experiences to build. The telehandler (8295) is a completely mad design, with connectors, colours, liftarms, and gears going every which way. By contrast, the cherry picker (8292) is neat, tidy, and organised to build. The excavator (8043) is different again, but again is quite an organised, structured build. Now, I don't have a huge collection, and thus haven't built enough to comment that much but Have you ever thought about this? Do you think you could tell if two designs were by the same designer? Which sets have you most appreciated the build process? (not playing with) How much do you enjoy the process of putting the sets together, compared with playing with them? On this forum we have an interesting mix of great MOCers, collectors, tinkerers, dabblers, scientists, and engineers. I'm interested to hear what you think.

The animations for the 1H2011 sets are up on technic.lego.com . They're getting better each release!

Thanks for your informative input - I love it how on Eurobricks there's always someone who's an expert! You just prevented me olive-oiling some of my LAs, so thanks. edit: removed all the <br>s introduced by the malfunctioning editor

Gee that sucks ... at least the process is completely reversible (once it warms up properly, the olive oil will all turn back to liquid). I wonder if giving them a good swish-around in a sink full of warm soapy water would break down most of the oil (if you want to get rid of it)

Ah, silly me I watched with the sound off - didn't realise he'd hit the clutch! So that actually is a useful measurement - both can push near 30N before physically giving way. If sheer force is the requirement, pneumatics have the advantage, of course, that it's easier to install many in parallel.

Lots of software can fix this for you. Assuming you're using windows, something like picasa works well. There are even online tools like picnik that can do it too.

Or not ... that comparison makes no sense. The force you get from an LA depends on the torque of the motor driving it.

It's just the gearing of the 8043 means that the motor stalls before the clutch slips. Plug a motor directly into your LA, run it to its limit, and you'll experience the delightful sound for yourself

Couldn't resist building one of these for the kids' soldiers and pirates ... this one's been hijacked http://www.youtube.c...h?v=HE1N58tvg5Y

I'm sorry you got trolled. I must say when I read that comment (someone linked to it from here recently), I thought that it surely couldn't have been you - seemed completely inconsistent with your postings on here. This is the problem with allowing anonymous comments on websites - they can get completely taken over. p.s. Loved your hand-powered pneumatic tractor that I saw in the technic challenge final

There is a solution - add them using a differential. But that solution might be a bit fragile for 2 XL motors

Very nice! It's nice to see an RC that is happy to use M-motors instead of XLs

First, as has been said - don't connect the battery boxes together - a small difference in voltage could cause current to flow backward through some of the cells which can cause a nasty mess, depending on what you are using. Let me briefly explain. You may well understand this, but others might not. What you want to achieve is to have each motor running on the maximum voltage that the battery can supply (e.g. 9V). The other limitation of a battery is current (amps). Ideally a battery would serve up the same voltage, and hence have everything connected to it running the same, no matter how much current was being drawn. More current gets drawn by loading the motors, or connecting more things. But in reality, the more current gets drawn, the lower that the voltage coming out of the battery is. This is due to the internal resistance of the battery. Different types of cells are better or worse - this is being discussed in a parallel thread at the moment. So running two motors off the same battery box will be worse than running one off each, although if you are using some types of power source the difference will be pretty small / negligible. What you should do depends on how heavily you are loading the motors. If the motors aren't working hard (revs near the no-load speed), then you may be fine to put them on the same receiver. If the motors are very heavily loaded and you have two on the same circuit, then you might hit the current limit on either the receiver or the battery box. You'll notice this because the power will just intermittently drop out. In that case you'll need to use two circuits, there isn't any other option. Lots of information on motors here: http://www.philohome...s/motorcomp.htm Things to try if you want to increase performance and use only 1 box/receiver - use NiMh cells, or if you have plenty of money, the 8878. If you want to get adventurous and don't mind wielding a soldering iron, you could try a 11.1V LiPo as Rien has done, but there are quite a few precautions to take, and I would strongly recommend connecting some diodes in series with it to lower the voltage to within recommended limits. edit: typo

Awesome! I really like this - nice combination of size, looks, and features

"like"

Wow, it looks really good. I love how compact the functionality is. Very nice car! I'm wondering how well the two XL motors will work coupled together that way, as that forces them both to run at exactly the same speed -- I would wonder if one of them would end up doing most of the work while the other has a free ride. But I'm not sure whether this would happen or not. I'm also guessing a differential adder wouldn't fit, or be strong enough. I'd be curious to see how much worse it works if you disengage one of the motors...