Dodgy Crasher
Okay so I'm new to this site so forgive me if this is a much covered subject, I have been flying years and only ever use 9g metal geared digital servo's in home build planes
but recently I got given a box of new in the wrapper , well 50 to be exact 9g analog servo's.
So, having googled this it seems they use less power than digital servos as there is less signal pulses and other boring stuff, I really didn't want to know how they work and what I want to know has not been obvious to me in my searches.
So here goes, why should I not use them in my parkfly jets, I'm just completing a J20 and I'm at the fit servo's stage , plus nearly ready to start cutting the foam for
Mig 29.
Will it be at my peril flying with analog servo's or will I not really notice the difference apart from more flying time, I do crank up to 125% throws on a few of my planes but a nano second delay in turning will not be noticeable, might be a problem in a racing drone but not a park flier I hope.
Any replies much appreciated.
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Sterling101
I've used both analogue and digital servos over the years and to be honest I've not noticed any difference between them in the air.

Certainly the most important thing I've found is the brand of servo. TowerPro and the many copies never last very long at all but eMax and Turnigy have been pretty good for me over the years.
Whoever said nothing is impossible had obviously never tried slamming a revolving door...
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solentlife
I actually prefer analogue as they will work with any setup.

Digital - especially in the cheaper versions can often have centering jitters ... 

Example : Extreme Flight Extra 58" ...... I bought this 2nd hand from an aerobatics guy who had crashed it and repaired. He lost interest in it and replaced with the later 60".
I fitted my FrSky gear and switched on .... Elevators started jittering like a buzzsaw ... If I touched them - they stopped and centred. If I gave a pitch command - when they should return to centre - buzzsaw again. I tried all the tricks of a bit of velcro / foam in the slot to give a touch of friction at centre ... even to using an elastic band to give tension back to centre.
I ended up ripping the servos out and replacing with analogue.

Honest answer ? For decades we only had analogue ... we flew precision aerobatics and scale .... why should it be any different today ?

I know OP said not to say how they work ... but I think it needs to explain the misconception of " it seems they use less power than digital servos as there is less signal pulses and other boring stuff," ... not strictly true.

The Digital servo has maximum power for any change of arm position by command. That means to centre - it has max power applied and cuts off at centre. Any pressure on the servo to go off centre is resisted by full power.
An analogue servo though has proportional power depending on amount of deflection required (I know the pulse width etc., determines the position required).
So in use ... the analogue technically has less resistance to being pushed off centre. The analogue will use as much power as a digital to deflect fully.
It seems logical then that you could assume the digital uses more power because of the centring etc. But in fact it doesn't work out that way. Many tests show that the difference is literally zero in general use ... in some tests the digital has used less.
OK - the centre jitter problem : This is caused by full power causing the arm to 'fly' back to centre and overshoot. The digital then detects and full power opposite way .. it gets into a very fast oscillation of a degree or so about zero ... causing surface to flutter and that buzzsaw effect. It is said that in flight - the airflow can negate it by putting pressure on surface to centre ... but I'm not willing to test that theory !!


I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Dodgy Crasher
Thanks for the speedy replies, so it's gonna be use up that box of new analog servos for me then, no point spending hard earned on something that is not going to be any benefit like another bunch of digital servo's.
I did use analog servos myself a long time back and apart from the odd misfiring one they worked fine, however everything was inferior then , radio gear, heavy planes, underpowered motors if you went for light weight,
But I have never tried mixing old style with new so your input has solved my problem.
👍👍👍 
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solentlife
There are two items I use a lot .... Wattmeter of course, but second one is a Servo Tester ... they are dirt cheap and are more use than just testing a servo ... you can test ESC ... run up a motor with one instead of needing RX / TX ... all sorts of tests that just need a RX type signal.
I centre my servos using one before mounting etc.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Dodgy Crasher
Thanks Solent, I have not looked at them before, found the one I'm gonna purchase on Amazon UK, there are cheaper at about £5 but the one I fancy is £15 so your right not a big cost and saves time centering servos,
I mostly but not always wire everything up beforehand, lipo, esc, servos, receiver and bind it just to do that one simple task, also would not be the first time I have built a model completely finished only to discover a faulty or sluggish servo.
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solentlife
I actually have two testers ... one is the $10 Hobby King one that has switch for different pulse rates (never had to use !) and a little $2 blue job that works perfect that was a free gift with some gear I bought ... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Tzicul
What I have read somewhere - if you use any kind of active steering control (car rc related) or, in our case, any kind of auto stabilization, it is recommended to use digital servo. May be true or not. However, when I used analog servo in one of my cars with steering control, I burned two servos. It may have happened because those servos was rather cheap, or maybe they couldn't take continuous input from the gyro.  
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solentlife
Burned two servos ? I would look at the voltage rating of the BEC output to RX / Servos and the maximum servo can accept.

There are still a lot of analogues out there that cannot accept more than the 4.8 / 5.0v .... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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DualDesertEagle
I've never tried using digital servos but I've been fine using analog ones for all sorts of stuff. I'd say the only time when digital servos with the benefits that I remember having read about them would be useful is profile 3D flying with snappy aerobatic maneuvers.

On the other hand, my F-18 had one HELL of a roll rate with analog servos and I didn't notice any lag between moving the stick and the according response of the plane, so if u want my honest opinion I have to say I don't see why digital servos even exist. They may or may not have been an improvement over analog servos when they first appeared but nowadays I can't imagine them being noticably better than analog servos.
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solentlife
The Heli boys swear by Digital .... 3D guys I fly with recc'd Digital ...... me ? I have mostly analogue but also some digital ..... with my flying ? They all crash the same digital or analogue !
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Dodgy Crasher
Well I will find out if there is a difference when the weather gets better because I have fitted a couple of Analog 9g Turnigy Aerostar servos on the ailerons of my just built J20 with a
40a hobbywing esc, an unknown chinese brand 22- 2750 motor, 6x4 bullnose prop, I like the sound they make at high revs and a spektrum 5 channel receiver, nope no gyro although I do like the little lemons with the gyro, not the 6 axis with the holy crap switch but the older 3 axis ones, keep it turned right down so it doesn't interfere and it just helps ever so slightly to keep the nose going straight in windy conditions, especially during cross wind turns.
Oh yeah and a 2200 3s lipo which i tend to fit in everything from my hair trimmer to my car keys and every plane I have lol ðŸ˜‚👍
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solentlife
I doubt you will notice any difference ... good luck
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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