ORIGINAL: opjose
ORIGINAL: mranga
1. Full size servos will draw about 250 ma of current on average (OKIknow the peak can be much higher and the at rest current draw is much lower). Is this a good working assumption for a trainer type airplane ( should Iassume less or more ?)
Ranga
I hope you are assuming 250mA for EACH servo average under flight loads when NOT at stick center.
If not you are underestimating.
A standard servo can pull down 2000mA at full stall. Ideally that should NEVER happen, but 250mAh and above is fairly normal at higher deflections.
At rest the load drops down to a small fraction of that.
Put a meter on your pack and move ONE control surface, say the elevator... while holding it like this, put a 4-8oz weight on the trailing edge of the surface and see how much draw you are getting from the servo... you will be surprised!
IMHO you should calculate a minimum pack size for a standard servo by taking 250mA x the number of STD servos used, to give you a good safety margin and proper duration for 4-6 flights without worry.
Opjose,
Correct. I am assuming 250 ma per std servo and 100 ma per micro servo, giving me a total draw (for this plane)of 550 ma. Thus, an estimated flying time of about 1.75 hours.
Thank you for responding,
Best regards,
Ranga