Do electronics deteriorate with age?Are metal gears better?

[Peter Coombe]

I have a number of unused servos from the mid 80s,Skyleader and Kraft.All were pretty expensive when I bought them.Most are ball raced and are assembled with ICs in circuit,and,I would guess,carefully hand assembled.They work well.Should I trust them? Seems a shame to bin what were,at the time among,the best available, in favour of a bewidering choice from the baffling array of incredibly cheap PRC products..Also can someone tell me what is meant by "metal gear"servos.Are the geartrains of brass,steel or what. How good is the quality of the gears?If you stub the control surface on the car door frame,what breaks first,the surface or the servo gear.Are there any plusses.?Thanks.

[Alan Cantwell]

i use several old 26M helical gear futaba servos, they are still work as good as the day they where made, as for metal geared servos, i have several futabas, and hi-tecs,

on the futabas, the intial drive gear is plastic, (dont know about the hitecs) this is its achilles heel, for break that, and its not listed as a part, only the entire gear system--after a suitable tirade, i managed to get some plastics, as for gear quality, you wont break them, but fits vary, also, with a seasons hard use, the backlash is VERY noticable, i would prefer a good nylon geared servo, there are several differant materials, from brass, to titanium, you pays yer choice, etc etc

[Alan Cantwell]

oh, sorry, missed a bit, only servos i will use are ball raced, mainly 3001s, futaba, this is the ball raced 148, digitals i dont need, or use,

[Tom Wright 2]

Peter i have quite a bit of modeling electronic stuff that was bought in the 70s/80s,i think if they have been stored in conditions that avoid corrosion ,there should not be a problem.

However some would say that the polarised electrolytic capacitors can deteriorate after 20 years or so ,but they are cheap and easy to replace.

TW2.

[Biggles' Elder Brother - Moderator]

Peter, I think as long as they have been properly stored, there is no sign of corrosion etc. they should be fine.

 

Re Metal gears; well I find it depends on the applcation. For example, I've got a smallish Pitts Special (42" span or so) that eats plastic gears on aileron servos - 1 flight, 2 at the most, and they're stripped. By the same token I've got a 72" span Chipmunk that has plastic geared servos on all surfaces (including flaps) and its flown for a year no problem at all. Of course the Pitts gets thrown around a lot more and the servo is driving two ailerons (top and bottom wing). So you see what I mean about it depending on the application.

 

BEB

[Peter Coombe]

Thanks guys,some useful and reassuring opinion garnered.Tom,if the capacitors are on their way out,would there be any visible evidence eg white deposit on "leg"?

In any event,they all work well,have been given the old 100 full deflections each test,so will use them.

 

The flood of minute servos,some with most impressive torque figures are very tempting arent they.Cheap to the point of throwaway,easy to install fit into tiny places,,high volt tolerance-we,ve never had it so good.Or have we. It will not have escaped us that they seem to be mostly marketed in conjunction with parts for small electric powered aircraft and this has obviously become a huge market .And all great fun,I,ve tried a couple.My bridle was sharply yanked when I installed a couple of (quality) minis into the wing of my almost finished 78"Stuka- minis necessary owing to space constraints.I stripped both sets of gears in quite short order just through usual workshop clumsiness.The collisions with obstacles werent particularly violent,I had just failed to adjust to the need for much greater care and attention when small servos are installed.Would have got away with it with standards-much more ding tolerant.I,ve just ordered some sturdy looking replace ments from BRC,but have stuck to nylon gears.By the way,I know of a very accomplished and competent modeller who installed standard JRs in a 60cc petrol Spitfire which has flown regularly and spectacularly for almost TWENTY YEARS and the servos have never needed replacing.Perhaps some of us worry too much,and £170 digitals are not essential for successful flight.

[Tom Wright 2]

Peter. White deposit on the lead outs could indicate loss off electrolyte,the seal at the base should be checked for swelling ,and if the top is split or distorted ,don't use it.

Re your final comment i would tend to agree,i fly a lot and i have never had a servo fail in flight ,but a bit of informed common sense goes a long way .

Several of my models have 9gram servos that cost £1.50 each even at this level not one has let me down, after all if one aileron servo did fail most sport models will be sufficiently controllable to get back to Terra firma with out damage.

TW2

[Chris Channon]

Hi Peter, today i was using a Simprop contest 180degree servo bought in the ,70,s still works well, i have an early Acoms four channel 27mgs set that i still use no problem, i think a lot of it is down to how it has been stored / looked after.

If it works ok and passes a range check ok then use it.

 

Regards

 

Chris.

[Bravedan]

Given the very low cost of new basic but good quality servos, the answer is.........20 plus year old ones will be fine, just make sure YOU are the one standing under it at the time.

And......Can I be there when you are explaining your reasoning to your insurers........

 

Boats and Cars, maybe........................

 

And yes I do still have all my Futaba "M" series in use............in cars.

[Chris Channon]

Hi, i did not realise that i would not be insured or have a problem if i carry on using my old Sanwa Vanguard gear, better get rid of it then !!!!!

( no chance really, it is brilliant gear to use )

Regards

Chris.

[Martin Harris - Moderator]

Posted by Bravedan on 05/03/2011 19:56:45:

And......Can I be there when you are explaining your reasoning to your insurers........

 

As it happens, unless you or your equipment is at fault the insurer will NOT pay out!

 

The BMFA insurance covers against a claim against you and is not a no fault automatic payout to anyone whose property or person your model happens to hit. Unless there's a law of the land somewhere that states a maximum age for a servo and you're not flying a 7kg model knowing or having reason to suspect an imminent problem with a servo there's nothing for them to discuss.

Edited By Martin Harris on 05/03/2011 22:04:49

[Peter Coombe]

Very interesting.Its really all a question of preference isnt it?Or perception of "fit for purpose".Is a 100mph electric' jet 'with factory fresh 9g servos(priced at £2 each) a less threatening proposition than-say a lovingly built, long term, trad built scale model,modestly powered and cautiously flown with older but tried and tested(and trusted)gear? I HAVE lost two models to modern cheap servos-both traced to lousy soldering of leads to pc board. On the other hand,I have some £5 standard jobs,from China, that will break your wrist if you try to manually restrain them,fantastic things.I appreciate that flyers involved in extreme aeros,with big surfaces and a violent and high stress flight pattern,have specialised needs,presumably only the best will do. Likewise,turbines and the real biggies.Its just that there are SO MANY and varied servos on offer.How does the punter know the good from the not good? Only an idiot would take a deliberate gamble with ANY part of the radio link,it is,a question of risk assessment. I ride a 79 Guzzi,had it from new,my son rides a Honda Fireblade.Technology cannot be compared,the Honda is lightyears ahead in every possible respect.Still prefer the Guzzi,even though it does get a bit sluggish around 120 per and have no plans to dispose of it. Old is not necessarily bad.Dont worry,Bravedan,have no plans to fly my old stuff anywhere near the club field.