DLuders Posted June 4, 2011 Posted June 4, 2011 (edited) On his website, Sariel (Paul Kmiec) posted a Lego "RC Motor Output Selector -- A mechanism that selects which of the RC motor’s two outputs is used, and can effectively work as a gearbox." Recommend reading the entire article; here are the highlights: "As you’re probably well aware, the [5292] RC motors are unique for having two outputs, with the inner output (the one closer to the middle) having roughly 35% more speed and less torque than the outer one. Usually when using an RC motor, one has to choose one output that seems better suited for the job. With this simple mechanism, it is possible to switch between one output and another, and since the outputs have different characteristics, it can effectively work as a gearbox.... "...even though I used two RC motors in the instruction, the mechanism can be used just as well with a single motor. It’s just that I and many other builders tend to use the RC motors in tandems. Additionally, two 6-studs long axles has been used as the output of the entire mechanism here, but you can obviously change it as you see fit." BIG LPub step-by-step Building Instructions are available there and on his Brickshelf gallery (when moderated). Here are the direct links to the 3 instruction pages: Page 1, Page 2, and Page 3. Edited June 4, 2011 by DLuders Quote
Sariel Posted June 4, 2011 Posted June 4, 2011 with the inner output (the one closer to the middle) having roughly 35% more speed and torque ... and less torque, I missed one word, ouch. Quote
Alasdair Ryan Posted June 4, 2011 Posted June 4, 2011 So what can this be used for if you dont mind. Quote
Sariel Posted June 4, 2011 Posted June 4, 2011 (edited) Well, it would be my guess than if you can switch between output that has more torque and another that has more speed, then it can work as a gearbox. Regular gearboxes rely on their internal gear ratio, this one here relies on the gear ratio inside the RC motor. Edited June 4, 2011 by Sariel Quote
DLuders Posted June 4, 2011 Author Posted June 4, 2011 Yes, it would be useful to have more speed (and LESS torque) at certain times, and vice versa. If one considers Zblj's Hyperbeast (in which he used two Lego RC Buggy Motors), one could get the heavy "beast" moving with the High Torque/ Low Speed option, then switch into a higher gear when it's moving fast on flat ground. Quote
Conchas Posted June 5, 2011 Posted June 5, 2011 Well, it would be my guess than if you can switch between output that has more torque and another that has more speed, then it can work as a gearbox. Regular gearboxes rely on their internal gear ratio, this one here relies on the gear ratio inside the RC motor. It is however too much weight added (from the extra motor), to implement such function, whereas it can be done with a "standard" gearbox!? Very interesting concept though! Quote
legolijntje Posted June 5, 2011 Posted June 5, 2011 It is however too much weight added (from the extra motor), to implement such function, whereas it can be done with a "standard" gearbox!? Very interesting concept though! I think, if you replace the right motor whit a beam, it works too. Quote
Sariel Posted June 5, 2011 Posted June 5, 2011 It is however too much weight added (from the extra motor), to implement such function, whereas it can be done with a "standard" gearbox!? But it works with a single motor too, and besides the extra motor adds twice the power, it's not like it's a dead weight. I'm a little confused as to why this concept appears so new and unclear. It's a gearbox that can change the speed/torque proportions by 35% while having just 5 gear wheels - Lego gearboxes rarely get more efficient that that. Quote
Odemit Posted June 5, 2011 Posted June 5, 2011 The concept is great, I suddenly want to hit bricklink for 2 RC motors! I think what might be confusing some people is that the thread header calls it an “Output Selector” when technically it is more of an input selector. So they are looking at it wrong. Quote
Sariel Posted June 5, 2011 Posted June 5, 2011 The concept is great, I suddenly want to hit bricklink for 2 RC motors! I think what might be confusing some people is that the thread header calls it an “Output Selector” when technically it is more of an input selector. So they are looking at it wrong. Yes, I guess so. I was thinking of selecting the motor's output. Quote
le60head Posted June 7, 2011 Posted June 7, 2011 Great stuff! Once again - THANKS Sariel! I'm seriously thinking about spending my next month's salary on two RC motors, partly thanks to the inspiration by your ideas Being keen on LEGO RC Models is not healthy for your budget, i suppose Quote
Milan Posted June 7, 2011 Posted June 7, 2011 Being keen on LEGO RC Models is not healthy for your budget, i suppose Being AFOL is not healthy for your budget. Quote
le60head Posted June 7, 2011 Posted June 7, 2011 true, but the 3 RC models and their components LEGO have released are especially "unhealthy" i think Sorry for the off-topic! Quote
Sariel Posted June 7, 2011 Posted June 7, 2011 Forget the RC models, I still can't get over the price of a simple pneumatic airtank. It appears to be one of the most valuable pieces of plastic ever produced by TLG. Quote
le60head Posted June 7, 2011 Posted June 7, 2011 That is odd, i agree. I am currently using a small 0,5 l. bottle from nestea, with two outer cable tubes glued to its cap. Works like a charm :) Quote
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