A guy at my field overheard me say I needed to buy one more servo, so he gave me one. It's a JR NES-517, which appears to be in perfect working condition but I know nothing about it (speed/torque etc.) All my other servos are Futaba S3004, so I was planning on using this for throttle.

Any thoughts?

If the servo works, it is OK for the throttle. You don't need blazing speed or high torque. If it has balzing speed or high torque, it is a plus.

A little over a year back, I picked up a bunch of kits and "Stuff" from a guy who was retiring from the hobby. Included was a couple dozen S148 futaba servos and some mini servos. Not the micro ones use on the foamys, but about mid way between them and a standard servo. I used a couple of them for throttle servos. Works great. I use two for aileron servos,replacing an single standard servo. More than a enough torque, in fact I gained overall torque and cut the weight by going this way in addition to being able to set up flaperons.

If you need an extra servo, and one drops out of a tree into your lap and works, use it. The only caution would be to not pair it with another brand/capicaty servo for ailerons. About eveything else is fair game.

Don

'k, thanks Don.

Its a discontinued standard ball bering 40 oz/in .25 for sixty degrees and three pole motor.

If its in good shape for most standard applications no reason not to use it for single servo functions. I don,t care for brand mixing when two servos are used on a Y chord.

If you are using futaba you will find this plug has no polarity spline and its possible to plug backwards into the Rx. No worries if you do it will simply not function reverse and play. It will not harm the Rx or the servo if plugged backwards.

Currently the big four Hitec S (universal), Airtronics Z, JR and Futaba J all use centerpin positive and all are interchangable with the exception of that peskey spline on the Futaba J plug.

Whatever you do don't use the wrong servo arms All four of the majors seem to have either different spline diameters and or spline counts and some combinations I have caught its posible to hold the surface and force a spline slippage. In other words if its a JR servo use only JR or JR specific output arms.

John

John, good advise. From my decades of main frame computer repair experience, I stick to one brand, right or wrong. We found on more than one ocassion, that while the "other companies" box was designed to "standards", our systems wasn't necessarly followin them, and they wouldn't play together nicely. Lots of finger pointing and such and the user caught in the middle.

Your advise about watching the horns is dead on. Little things like that can really trip you up.

Don

Thanks. I actually remember hearing about the different servo horns on different brands. This one has a horn on it already, so that's what I'll use.

I was mainly concerned with speed, power, and aircraft approval (vibrations?) I prefer to stick to one brand as well, but as said above, "if a servo falls out of a tree..."

The 517 is a standard servo and I use them in a number of positions. J. Buckner gave you a good run-down.

I don't mix servo brands on same surfaces like ailerons. There have been some that mix brands such as Hitec and Futaba (maybe it's JR) on elevators because they rotate different directions and therefore no need for servo reversal wiring.

The 517 will do well on any application that can use such size servo. On ships up to 45 power, I find 2 standard servos, 4050 oz. torque work very well on elevators or ailerons and 1 functions fine for rudder/nosewheel/ or throttle. Heck back in the '70s one servo working both ailerons was the norm, even on the .60 size pattern machines. Back then a servo cost 40-50 yankee dollars and that was a lot of money, in the '70s.

Lots of marketing hype in the servo world. Lots of relative newbies hear the field-deep-pockets-"expert" say something so relative newbs repeat such as they also become instant experts.