Do servos have a use by date?

[KiwiKid]

I have several models that (despite my best efforts) are getting, shall we say, a bit long in the tooth, the most elderly being over ten years old. It's an EDF Skyhawk and clips along at a pretty good rate, so any glitches would put her in the dirt pretty quick - vid below. It is on it's second motor and third fan unit, but still has the original servos. They seem to be chugging on fine, but I was just wondering what others experiences are with elderly servos.

[David Ovenden]

Well, I have several standard-size JR servos (Coreless motors and made in Japan) from the 1990s still working perfectly in models after nearly 25+ years. I also have a Tundra RTF electric model from Hobby King and 4 of the pre-installed 9g servos (made in China, with no maker label) failed within 2 years.

So I guess it depends on the quality, size, use etc.

Edited By David Ovenden on 14/07/2018 06:32:06

Edited By David Ovenden on 14/07/2018 06:46:47

[Chris Walby]

IMO servos are electro mechanical devices so it follows that they will eventually fail!

Mechanically they will wear out in the very end, but would say failure to be more stress and loading related for a early demise.

Electronically we have various bits of equipment 20+ years old and what seems to kill them off is lack of use/storage without power on. So carry on with the good old stuff as the newer cheaper probably won't last as long!

[Rich too]

I am interested in this too. I have just inherited (early!) a Glens models 25% Sukhoi, finished approx 15 years ago and never flown. I am wondering whether it will be safe to use the servos...

[Former Member]

[This posting has been removed]

[Bob Cotsford]

From recent experience - check the cables for any hardening of the insulation, this can lead to fatigue fractures of nearby soldered connections - Futaba 3003, genuine, not a cheap copy. Exit one WotsWot.

Other than that, metal gears wear, older feedback pots get noisy.

[Martin Harris - Moderator]

There are far more significant factors than age. I've had (decent quality) servos fail on initial power up and 30 year old ones that still function perfectly.

Life is affected by factors such as exposure to vibration, heat, load, shock damage, supply voltage, linkage problems etc.

Percy's advice to soak test unknown (and new) servos is very sound and will help identify intermittent problems and early life failures but as he infers, this test only guarantees that the servo worked properly on test - failure could be just around the corner but it comes down to acceptable risk assessment. I believe the important thing is to look carefully for any clues such as a slight glitch now and then, lower power than expected, any sign of mechanical wear (slop or roughness in gear trains, excessive output shaft play) and external damage.

[Don Fry]

I get the impression that used servos coming out of storage, seem to have more duds than expected..They were tested going into the store age box, but a dud coming out. Usually a feedback failure to centre properly.

As a group I suspect we don't test and check servos enough, in service in the airframe. I know I don't.

[Rich too]

Thanks gents. I am still undecided, they are Futaba s3001 which I understand are good servos but the Sukhoi is so well built and a lot of effort spent on covering it I don’t think it is worth the risk. Mmmmm....

[Don Fry]

Test them, Percy Verence style. Check the wiring. Just because you buy new, why do you think they are better.

Years ago, might still be, you used to be able to buy electronic components that had a fixed amount of use. Paid a lot more for them. Because most failures are related to a poor initial manufacture.

[Former Member]

[This posting has been removed]

[ASH.]

+1 for Futaba 3001's. I use them on all my medium size sports models. They have indirect drive, have a bearing and the torque is 3kg on 6V.

With a 25% Sukhoi you may want more powerful servos if you use a powerful engine and plan to do any 3D type of flying. 3010's should do the job.