Servo size calculation

[Hostage-46]

Can anyone point me towards a resource to determine proper servo specs for a given model.

ie, wanna make sure I purchase the proper servo for the proper application

Dan

[Ollie]

See:
http://www.multiplexrc.com/calcservo.htm

[eos1]

The multiplex calculator seems to work. Another old standby to find the right starting point when offline is to assume ordinary speeds and use the formula 0.075xarea in sq.cm = torque in Ncm

[Hostage-46]

I could not get it to work.

Tried In explorer and Netsape.....

[eos1]

Yes, there seems to be something wrong with the cgi-script, probably due to the updates they're making on the whole site.
The calculations from the old formula gives quite useful ballpark figures if you have the servo torque figures in metric units. I'm in Sweden and we use metric only. Conversion factors for torque can be found at http://www.merkle-korff.com/convformulas.html, 1" = 2.54 cm and 1 sq.in = 6,4516 sq.cm.
For example if you have a rudder that is 12" high and 2" wide that is 24 sq.in = 155 sq.cm, that gives a necessary torque of 11 Ncm = 16 oz-in.
It works for normal IC speeds and deflections, on a fast or aerobatic machine use some kind of fudge factor based on your own experience.

/Peter

[GordonTarling]

Try this one -
http://www.csd.net/~cgadd/eflight/calcs_servo.htm