Everything else being equal ... what requires more torque in a plane? The rudder or the elevator? My gut says that the answer would depend on the "type" of flying in question, (eg 3D flying vs a warbird?) so since I'm building a warbird, let me put it this way ... what requires more servo torque in a warbird? The rudder or the elevator?

Thanks!

Colin

If you are keeping everything to scale and you know how to make the surfaces hinge freely with no resistance to movement - yet no slop- then use same size servos unles you are steering the tailwheel with another servo.
Don't skimp!
I build scale/warbird/IMAC and little stuff and the only cases where a really heavier duty servo is necessary is on the 3D stuff with big rudders.
Lots of 3D flyers are constantly wagging the rudder and the highest load on a servo is during quick direction reversals -- You can proove this with a meter in the circuit. You are effectively stalling the servo over and over

Thanks Richard, I guess the reason for my question is that in this particular application that I'm using it on, (20lb Typhoon) I have the two servos that are both basically overkill for either rudder OR elevator.

However one of them does produce more torque than the other so I just wanted to know which surface I should use the more powerful one on ... rudder or elevator?

Colin

On that size model - I would want std size servos - to have min 90 in oz - speed not important.
This size servo typically has stronger gears -and if all works smoothly the servo will never be taxed - which means it should not overheat or fail
Last year, a DA50 powered P51 with retract/flaps etc., that size, for a friend - used 140 in oz at 6 volt servos on everything.
battery power was A123 2300ma -
the idea is to have lots of overhead - that is the servos and batteries are never taxed . This was a model using a 2.4 radio system- - Lots of work in a good scale project - skimping on radio and power just isn't worth it.

I would always put the stronger Servo on the elevator. If this one stalls, you have a problem. As stalled rudder is no problem.

This link may be of interest to you.
http://www.mnbigbirds.com/Servo%20To...0Caculator.htm

Curtis

Does the rudder also have a steering linkage?

Originally Posted by Julez

I would always put the stronger Servo on the elevator. If this one stalls, you have a problem. As stalled rudder is no problem.

.
If the plane has ailerons....
Had a rudder servo strip while it was way up there.. and only elevator and motor on the plane. Careful stalling and motor running got it back to land at my feet.

Originally Posted by 1320fastback

Does the rudder also have a steering linkage?

Yup

Is the steering linkage spring limuited? A rough landing with the rudder deflected could well strip the servo or linkage if it was not allowed to deflect somewhat.