It seems everyone hovers around the brand that matches their radio or their favorite customize your R/C for HOT action article.
Futaba seems to be one of the most popular, but frankly, I haven't been able to tell much difference. They come classified by traditional or digital (I still use traditional, but may move over to digital when I get time to better understand how to interface them.), they are classified by holding torque, best end to end transit time and weight (or size). They are often called, micro, mini, standard, large and very large. A lot of the micro units go into HO layouts (as in the previously referenced article). For larger loads and applications where more holding torque is required (that also translates into power for movement), you go up to larger, more powerful servos from there. As to quality, the cheapest ones, which are generally fine for most railroad applications, you'll find the gears are all nylon or acetal plastic and they use bushings (usually also plastic) to manage the torque moment. For a somewhat higher price, you can get metal gears and bearings, though for these applicatons there isn't enough movement over the track lifetime to justify the extra expense for most applications (IMHO). To see it in perspective, I have a set of old standard size servos in a large R/C plane I built 23 years ago. They still work fine, even after the plane got turfed (hard crash) several times, requiring a complete main wing rebuilt each time. On one occaision a friend was flying it and got confused about the attitude of the craft and plowed it in so hard the only part that was intact was the instrument box in the main fuselage. Because of the kind of construction I used, I was able to completely rebuild the plane from the instrument box out. I never had to replace any of the servos and to this day, they work fine. These are the less expensive plastic gear servos that today run about $12 (although I paid quite a bit more for them at the time). The message here is that servos are actually quite robust and somewhat forgiving.....if you correctly size them to the application. To do that, you must determine the amount of force required to move the object of interest (large ailerons in the realm of 50" require considerable torque, track switches require quite a bit less). That is why Don calls out micro servos for his HO examples i his article. For S, I might suggest a moderate mini servo. For the last three years, for non-R/C applications (I've hung up my R/C gear for awhile), I've been buying most of my servos from HobbyKing (link: http://www.hobbyking.com/hobbycity/store/uh_index.asp <http://www.hobbyking.com/hobbycity/store/uh_index.asp> ). Now I'm not promoting that business, but I am explaining what I've done and am doing in the spirit of sharing information. You may prefer to buy local, or have a favorite vendor you use....and that's just great. I buy most stuff online, since I'm way out here at the end of the pole line in a rural community and they just don't offer much in the local establishments that I need for my various interests. HobbyKing carry a pretty good variety in almost all the available sizes. Their EM 9g offers a 1.5Kg (about 53 oz-in or casually 3lb-in) holding torque and a 12 second end to end transit time. Very adequate for most small motion activities in a layout (and easily used for some lighter switching in HO applications). For switches in S-Scale, I imagine something more like the Corona 939MG for $4.30 offers nearly 5lbs holding torque, metal gears, ball bearings and a 14 second end to end transit. I haven't tested that yet. If you get a switch built up and can tell me the moving force, I can suggest any number of servo options....and I'll bet they'll all be under $10. If you want to see someting really beefy, look into their BMS620-MG..... metal gears and bearings, weighs less than 2oz (for you weight watchers), 15 second end to end transit and 9.1Kg (that's 126 oz-inches or, as I've casually been calling it, over 20lbs) holding torque. Um, that's lb-in for any technical sticklers. The rating is always in Kg-cm or oz-in at this scale. This one could easily turn an S-Scale swing bridge of 120 scale feet. In the really big, as in "we need to build it, 'cause they don't make them", you have to get into a little machining and find a good gear supplier, use moderate, but larger motors, etc.. That's much more involved and costly...but some folks like that "make it from scratch" kind of thing. I confess to a certain amount of that....that's one reason I'm here. Anybody can go to yon HO store, buy a bunch of ready-built stuff off the shelf and assemble a very nice track and control system. I had a friend that built a beautiful store window display in HO and N scales completely from off the shelf purchases. The store was delighted and he was well paid for a fun shopping trip and four days of painting, gluing and wiring (with a little help on the electronics from yours truly). I was not paid, since I owed him a favor. But it was fun anyway....and he got well paid. These are great for scale action elements, because they can be controlled at a scale rate (much slower than these transit times, especially nice, since one usually only needs a portion of their total "throw". Most will rotate at least 180 degrees, many as far as 300 degrees. And, of course, if you take out some of the encased elements, they just rotate (not really servos any more, but controlled with the same electronics)..... Ad of course, they carry Futaba, if you want to have shiny buttons and less cash in your pocket.... ;-] Now I've been a wee bit flip here (and gone on too long again), but I hope this will provide a reasonable starting point for you and anyone else that is interested in useing servos, but uncertain how to proceed. Best Wishes to you and all the group, Chuck --- In [email protected], "Michael" <meldridge@...> wrote: > > Any thoughts on durability of various brands? Is there a brand you prefer? > > -Michael Eldridge > > --- In [email protected], "chuckcluff48" chuckcluff48@ wrote: > > > I can't actually make any claims to originality for the use of servos > > for active but non-rolling elements of a layout. I have considerable > > other experience with them, but that is irrelevant here. > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! 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