How to select the right servos for the job

[socalrcpilot]

I am relatively new to this hobby and im enjoying the heck out of it! I have found that there is a TON of stuff to learn but i cant seem to be able to find any good advice on servo selection ie:
Brand selection
proper size
metal vs carbon vs plastic gears
digital vs analog
etc.

Anyone around with some good info?? Maybe even a video from you or flitetest???

 

[Mike oxbig]

Servo selection is a bit of a subjective thing. Ask 5 people what servos will work and you'll probably get 5 different answers.

On kits and arfs they tend to give a recommended size and torque so that makes it simple. A general rule of thumb is go with the fastest servo that you can afford that will deliver your rated torque. Torque is a necessity as too little will stall the servo out and not give you the performance you want. Speed is a luxury as it will increase your reaction time to inputs but going slower will not decrease the performance of the surface.

Plastic vs karbonite vs metal. This is really a personal preference. On planes up to 60 size I normally just run plastic. Plastic gears will break in a hard crash but I've found it rare. Generally on that kind of crash the damage to the airframe cost way more than a couple of bucks for gears. On the little guys I run hs 55 servos and the plasticgears are only $3.00. I have hs 55s from 5 years ago that have literally been on a half dozen planes and still work.

In my 450 helis I run karbonite hs 65s. Plastic geared servos were too weak and easily damaged. I ran metal geared ones before but in a hard crash I found that if the servo gear didn't strip the servo could burn out. Karbonite bridges the gap, I don't strip out on every light crash and I don't burn up servos. On my bigger helis the was only mg servos that offer the performance needed.

 

[lobstermash]

As Mike said, there's a huge range or servos out there. As a general rule, the more your plane costs, the more you're going to want to spend on servos.

A very popular servo is the HXT900, which is a 9g plastic gear analog servo for under $3 from Hobbyking. These will do the job in pretty much anything from 200g-1200g planes (in which range your first few planes should be).

 

[jetpackninja]

I get by mostly with two different budget servos-

The HXT900. They are cheap, but I trust them well enough to be used in my hopped up Supercub and my not so Slow Sticks.

The MG90s. Just slightly heavier. I use these on flying wings with large surfaces that love to strip gears and on anything expected to see any combat.

I do like a slightly stronger servo for my larger wings (HS82MG)

Bigger planes where the weight penalty is not a big concern can often get by with an inexpensive standard size servo.
(like a big FPV flying wing)

The precision of a digital servo aren't really needed unless you are wanting to fly gliders or precision aircraft where you want the servo to very precisely center itself repeatedly and reliably.

Brands are largely a preference thing...

 

[socalrcpilot]

I really appreciate all the info, keep it coming - the more i know the better i feel about selecting servos for hop ups or scratch builds

 

[bicyclemonkey]

If the plane calls for a micro servo I use either of these depending on which is in stock.

Turnigy TG9e
HXT900

If it's electric and calls for standard servos, these:

Hextronik 5010

If it's gas/glow or electric heavier than 10 lbs I go with these:

Solar Servo D228

I'm actually considering a switch to the Solar metal gear digital after I use up all my current stock of analog servos. Can't beat those Solar servos for $10/ea.!!!