General Purpose Servo

[Ashley Hunt]

Does anyone have a view on general purpose servos. I need 5 for a new model that I’m building. There are still a few reputable shops around selling the Futaba S148 servos which was in my mind was a good basic servo. Does the Hitec HS 311 compare favourably, or is there anything else on the market in the same bracket ?

Thanks

Ashley

[Richard Wills 2]

Savox 0351 is a good sport digital in the same price bracket as a standard Futaba. Worth considering.

[Jon H]

the 148 has been the standard budget servo since the 80's i think. the 3001, 3003 are also good options.

I am a fan of the hs311, 322, 422 etc but my only moan is they have an even spline on the output so you cant mechanically centre the arm by rotating it like on futaba and savox servos.

I use the higher spec savox servos in my warbirds (6-10kg digital) and like them alot. I have some 351's, 352's and 252's if memory serves. The 351 is good if you want a little more than a basic servo so it all depends on what you want it for. A trainer or a sport model is not likely to notice the difference, but if you have a bigger aerobatic model for say 90 4 stroke then the savox 351 will give that little extra precision and power.

[kc]

At less than half the price of the 148 these standard servos from 4 Max seem attractive. 4Max have a list of servos here with both their own brand and Hitec 311 etc for comparison.

[Ron Gray]

Don’t ignore Corona servos from HK, good centring and excellent value for money.

[Skippers Walker]

I have several Futaba S148B servos in use, very reliable too. The Corona 339MG seems to be a good replacement and a bit lighter & smaller as well. rclife.co.uk or Hobbyking perhaps?

KBO

SW

[Frank Skilbeck]

Yep the 148 and 3003 have been good reliable go to servos for many years, not tried any yet but Futaba have the new SU300 slightly higher torque digital servo for just slightly more.

[Ashley Hunt]

That’s all really useful information. Thanks very much.

[Martin Harris - Moderator]

I've been pleased with Corona performance - not so impressed by their brittle mounting lugs.

[Matt Carlton]

I've used Futaba 148s and Hitec 311s for years without any problems. I think some of the bad press some servos get is down to incorrect application and poor installation and connection.

[Martin Harris - Moderator]

I'm not sure if the comment above was aimed at me but I must point out that my experience with cracked lugs has only ever been with Corona servos.

[Bob Cotsford]

Posted by Martin Harris on 27/10/2020 19:43:13:

I'm not sure if the comment above was aimed at me but I must point out that my experience with cracked lugs has only ever been with Corona servos.

^^^^^^ What Martin said. I've had three or four Corona 339 servos shed their lugs while mounting them. It's taken high speed impacts to break lugs on any other brand. I have however used quite a few other 339s over the years without breaking the lugs.

[gangster]

Since the 80s I have seemed to have automatic chosen Futaba148/3001 or Hitec 422. Never had any issues at all with any of them

[Trevor]

+1 for Corona servos. The mounting lugs on some are certainly a weak point but, to be fair, I've only seen them fail after a crash, not in normal use. I do though still have several models with Futaba S148s - and even a few with 128s - still going strong after more than 30 years.

[J D 8]

In our club we had a expert builder/flyer who died just a year after retirement.His last large scale project was a Beech 18 twin with 32cc petrol engines I think. It went on to win competitions in other hands.

I asked him what servos he used in the Beech ? 3001's he said the same as he always used just more of them.

Good enough for Brian so good enough for me.

[Basil]

Hi, I am a newby. can someone explain the basic differences in 'Micro' , 'Sub micro' and so on. Also how does one select a suitable 'Load' capability(Kgs). I find it very confusing at the moment, all I do is follow the suggestions of the designer/builder , but would like to follow the logic or science behind it. Thanks in advance.

Bas

[Matt Carlton]

Martin - Not aimed at you at all, merely that I have been repeatedly told that 311s in particular are prone to failure when that hasn't been my experience. I have seen some truly bad servo installations from a particular (not on the forum) complainant, with grommets missing, servos touching fuselage sides, badly aligned mounting rails, badly aligned connections needing a lot of pressure to bend round to the servo arm etc etc. Yet they insist that the servo is the problem.

Similarly, one reads things like;

"brand x are no good, I put one on the rudder of my 120cc 3D model and the gear stripped within 6 flights. Really slow and poor holding power too"

I would say that most (not all, granted) servos nowadays are generally pretty reliable and adequate for the task if they are used appropriately and we don't ask too much of them.

[Nigel R]

Nobody has asked what you are building yet - what are you building?

That aside, Hitec analogues are always my go to.

311 are perfectly good standard servos (although worth going for 325 instead, they have a ballrace on the output shaft). Standard old school design with single top bearing and the lower bearing is, as was common, also the feedback pot.

The 422(bush)/425(2x ballrace) have a lower bearing for the shaft, so a slightly more durable setup. They are a little larger/heavier because of that. 485 is same size but more torque.

If you are building something 10 / 15cc range, I would use 425s on aileron/elevator and a 485 on rudder.

20cc region, can't speak from experience, but I would think HS625 or 645 or larger.

[Ashley Hunt]

In answer to Nigel R

The model is a Top Flite P51 Mustang. 60” wingspan, Irvine .61 powered.

[Engine Doctor]

Whatever you decide on make sure they are not fakes/ copies. Buy from a lms or a known supplier. Futaba copies that are plain dangerous are still being sold on an online auction site, usuall prices 4 for £10 or 5 for £12 ish. They even have a Futabe name sticker that's blurred out in the pic on the site. There are now even copies of Tower pro servos ? Beware ,if the price looks too good to be true it usually is.

[Nigel R]

I'd go 422 or 425 elevator/aileron/flap, 485 on the rudder. Throttle, anything really.

 

edit: second the above about buying from a proper shop, I've been stung with a few fake Hitecs

Edited By Nigel R on 28/10/2020 09:57:29

[John Wagg]

Posted by Engine Doctor on 28/10/2020 09:52:06:

Whatever you decide on make sure they are not fakes/ copies. Buy from a lms or a known supplier. Futaba copies that are plain dangerous are still being sold on an online auction site, usuall prices 4 for £10 or 5 for £12 ish. They even have a Futabe name sticker that's blurred out in the pic on the site. There are now even copies of Tower pro servos ? Beware ,if the price looks too good to be true it usually is.

+1 - I recently came back to RC and bought some Futaba 3003 (?) of Ebay. They work but the centering is very poor and are noisy. The same for some mini servos which I replaced with some from 4-MAX. The 4-MAX ones centre spot on and cost only a few pence more.

Lesson learnt.

[Martin Harris - Moderator]

Posted by Doc Marten on 28/10/2020 09:21:33:

I've only had 2 Corona servos and the mounts crumbled on both when I was using them to drive the ailerons. I also found them very noisy.

I now stick with genuine Futaba 3001.

I do tend to use 3001s on most models - short of larger high speed aerobatic models with large control surfaces they seem quite adequate for average models, despte their modest claimed output torque and probably more importantly, they have been very reliable.

However, my Coronas have worked very well too and I actually reclaimed some with failed lugs by aralditing some aluminium mounts to their cases:

P.S. Regarding mounting errors, how many people put their metal "top hat" spacers in the wrong way up i.e. with the screw head contacting the "brim"? Almost every second hand model I've encountered has them this way up allowing the spacer to bite into the mounting surface, ruining the controlled pre-loading of the rubber mount!

Edited By Martin Harris on 28/10/2020 12:10:56

[Nigel R]

"despte their modest claimed output torque and probably more importantly, they have been very reliable."

I believe Futaba's torque claims (and the rest of their specs, too). Many, how should I say, cheaper brands? I do not.

[Matt Carlton]

It's also worth pointing out that the published torque figures may not be what you get, depending on the geometry of the control horn and servo horn.

 

Edited By Matt Carlton on 28/10/2020 14:13:01