golf4two

Scratch building a Dalotel (for Sunday type aerobatics), 48-50 in WS, Saito 30 Four Stroke for power. No idea of final weight.
I'm used to nitro planes in the 46-90 size range so not familiar with the smaller planes requirements.

Putting together a parts list before final design and build. Was wondering if Futaba S3114 High-Torque Micro Servos ( 28.8 oz-in torque) would do the job for control surfaces (two aileron servos, one in each wing).
(Yep, I'm a Futaba guy!) Or would something a little more powerful be required. No 3D, just Sunday aerobatics.

TIA,
G42

600Bob

I read someplace, right or wrong I know not, that 1 oz. of torque per 1 sq. in. of control surface area is a good way to size a servo.

golf4two

Thanks Bob,
If that formula is true, 1) I'm in the right ballpark, and 2) What a cool formula to have in my bag of tricks!

G42

Lone Star Charles

I found this link a whille back about servo sizing. http://www.mnbigbirds.com/Servo%20To...0Caculator.htm I've used it to double check servo selections that kit manufacturers have recommended and it seems to be adequate. See what you think and let us know.

600Bob

Looks good, bookmarked for future reference.

golf4two

Nice formula page Charles. Thank you.
For my application at least, calculator shows much less ( 1.605 oz-in) than the one oz-in per sq in (30 oz-in).

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Tried to upload a screen shot but don't know if it worked.
The calculator in this instance doesn't seem realistic. Maybe it's the small numbers.
When I get some time during bad WX will run it against some of my current models as outfitted.

G42

jester_s1

I'd think just from experience that those would work fine. A .40 size Stick or other sport plane will fly fine with 50 oz in, and that's roughly double the horsepower up front and considerably more weight and control surface area.