servo, battery choice

[benransom]

I've not got a lot of RC build experience and would appreciate a sanity check on what I'm thinking for servo and battery choice.

I recently bought an oldie Czech glider, 2.660m wingspan, balsa wing, T-tail, fiberglass molded fuse. Wings were completed by previous owner, and there are micro servo bays for each flap and aileron (so 4x). I think I'll complete it as a pure glider (although motor mount and instructions are there for electric option). Wing area is 48.8dm2 and wing loading is 39-43g/dm2 if electric (so can be lower if pure glider).

I'm new to selecting servos, etc, so would appreciate a sanity check. I'm thinking -->
Servos (6): corona-sb-9039-servo-2-7kg-(37-49oz)
Battery: liperior-2100mah-2s-20c-6-6v
I already have an Archer Plus GR6 Rx that I'll pull from another 2-ch oldie.

Seem good? Any comments welcome -- TIA

 

[benransom]

BTW, Instructions recommend (~25yo technology):
2-4 micro servos at 15-20g ea and at least 600mAh battery.
So the Corona micro servos at 12.5g should be fine, but I'm esp unsure that maybe the battery is overkill on capacity (and weight).

 

[Wayne]

First off - Pretty plane!

Those servos will work just fine. But if you are open to others, I'd suggest either the Orbit or Emax options:

Orbit Eris Digital Servo - 4.7kg (65oz/in), 0.10 sec - 8.5g Metal Gear

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or

Emax ES3352 Thin Digital Servo - 2.8Kg (38.88 oz in), .10-sec - 12.4 Grams

Emax delivers a quality thin wing servo with a great price!

alofthobbies.com

Good servos and should serve you well.
Battery will be fine as long as you have room for it, I suspect you will have a lot of space in the fuselage.

 

[benransom]

Thanks very much, Wayne. A side question...
Servos rated for something like 3.5-6V (such as the Orbit Eris), I suppose that means they're supposed to function if a 6V rated battery drains down to 3.5V? And fine to assume a 6V rated servo is happy with a 6.5V rated battery? Or more generally, do servos have some small bit of overvoltage protection?

 

[Wayne]

Both of those servos will be fine with 2S LiFe battery voltages.