So, I was wondering what should I look for in terms of servo properties for setting-up a pattern plane. High speed? High torque? Centering?

I'm building my first larger pattern plane, so I'm trying to determine what's best to spend my money on.

Thanks,
flyingtomg

Others will have their own likes and dislikes, but my priority order would be centering, torque/speed. If the servo has too broad a dead band and doesn't hold center well thru MANY flights, trimming is extremely difficult.

Basically, buy the fastest and strongest servo that centers well your wallet can stand.

You can have a high torque, slow speed servo which won't work on critical controls. Vice Versa is also true, high speed/low torque won't work either. Personally, I fly Futaba servos and really like them, others feel the same about JR, Airtronics, Hitec, etc. They all make fine servos.

For ailerons (one on each aileron) a GENERAL could be 70 oz/in at .13 seconds (or better). Elevators total of 90 oz/in and .13 seconds (or better) and rudder 120 oz/in (or better) should probably work on a 2M plane. As I said, these are general guidelines. Far better specs for servos are available depending on your wallet or credit card. Others can chime in with torque/speed values and servo recommendations. Don't ignore the throttle servo if you are running IC engines. You don't need as much speed and torque here, but you do want it to center well.

Woodie

Since centering isn't listed in the specs of servos, how do I know which ones center well? Is there a resource on the web somewhere?

Also, will a servo programmer help? I see you can program the servo's center, but does that mean it will return to that spot every time?

Thanks again.
flyingtomg

Only Hitecs are programmable in sizes of servos we use. Generally, Hitec digitals have not had as good resolution, deadband, and centering as JR/Futaba. Hitec's had about 4 usecs of deadband, and JRs/Futabas about 1 or less. That is with the Hitecs programmed to the least amount of deadband. There are second generation Hitecs coming out, and I don't know about them, but they are just as expensive as JRs and Futabas. For pattern, the programming has little value. I haven't used Airtronics, so I can't talk about them.

I use JR. DS9411sa's for aileron, DS3421sa's if I use split elevators, and DS8417 if I use a single servo, and a DS8611a on rudder. The DS8411sa has enough torque for rudder, but I've had issues with them oscillating around neutral on rudder. Never had an issue with a 8611a.

All good information, as I am also looking to put together a pattern plane.

How about digital vs analog, coreless vs regular, etc. How about vendor claims that a servo is "high resolution"?

My scant research tells me that digital helps with torque and speed, coreless is faster... but no where can I determine which servo technology will take advantage of my TX/RX 2048 resolution capability.

Thoughts?

Best... Roger

Take a look at this thread.

http://www.rcuniverse.com/forum/m_42...tm.htm#4275896

Why are nylon gears preferred?

Nylon gives less play/slop in the servo gears.
Also remember to use 1" servo arms, ball links and the best hardware - NMP and MK are generally used.

the Nylon gears will make the servo alot lighter....also the nylon tends to be able to take the vibrations of the motors and things like that..and not create a slop in the gears.

I just started bls451's in my alierons and elevator and a coreless s9155 on rudder and have really ejoyed them thus far.