When it comes to servos for a 100cc to 120cc 3d aircraft. How much torque do you want on your rudder? Is it still necessary to run 2 servos on your rudder when your servos are making 400 oz+ of torque?

I run one JR S8911 over 800 oz with a single servo.

I ran 2 8911s on my rudder, I know Frank Noll does the same. Both planes were pull pull, one is more than enough though, especially if mounted isn’t the tail.

One Savox 2290 on the rudder on my 104 Extra V2.

I use a single Hitec D980 on my 2 120cc bipes. They provide 611oz torque with the 7.4 lipos I am using. My 120 Viking and my Bulldog are set up with a pull pull system and I haven’t had an issue with blow back doing 3D or high energy aerobatics. 2 smaller servos would give some redundancy though.

Run 1 servo, of over 400 oz in of torque on your favorite battery flavor. I prefer push pull. But 1 servo will work in pull pull configuration.

promodeler 630 HV

Great info guys. I was thinking one servo would be fine, bt like to hear it from others

Originally Posted by ghoffman

One Savox 2290 on the rudder on my 104 Extra V2.

Same here and works great! If you dont want to spend much money you can also use a Savox 1270, have used a single one for rudder with great results as well.


Memo

Only issue I think there could be with running just one servo, and I've seen this stated in other threads here on FG, is all the force is being applied to a single gear set. No question the servos available now have enough torque, but how long will a single set of servo gears take all that pressure? Especially if you're flying 3D/XA.

Originally Posted by Shawnlh

Only issue I think there could be with running just one servo, and I've seen this stated in other threads here on FG, is all the force is being applied to a single gear set. No question the servos available now have enough torque, but how long will a single set of servo gears take all that pressure? Especially if you're flying 3D/XA.

I like 2 servos in a SWB self-adjusting servo tray for 2 reasons:

#1 Redundancy
#2 To spread the load out to 2 servos

This setup yields tons of torque and a reduced load on a single servo, no matter how much torque it has!

Originally Posted by STLAV8R

I like 2 servos in a SWB self-adjusting servo tray for 2 reasons:

#1 Redundancy
#2 To spread the load out to 2 servos

This setup yields tons of torque and a reduced load on a single servo, no matter how much torque it has!

#1 redundancy ? seems like an obsolete issue with all the new gen servos. ive been using single servo in ail and rudder on a couple of my 35%. comp arf edge had 1 servo/wing and one for rudder. 400oz min servo required

Not sure on longevity of a single rudder servo for everyone, but top pilots like Jase Dussia have been using single rudder servo on 120cc planes for a while now. I personally ran a Savox 2230 on my 120cc plane for 160+ flights/29+hours before I dumb-thumbed it. Transferred all of those servos (6 Savox 1270 & the 2230) to my 120" TBM, and have another 60 flights on that. That same 2230 is still going strong on the rudder of the TBM, with little slop or any other issues

Originally Posted by airboss/oc

#1 redundancy ? seems like an obsolete issue with all the new gen servos. ive been using single servo in ail and rudder on a couple of my 35%. comp arf edge had 1 servo/wing and one for rudder. 400oz min servo required

Apparently you haven't had a rudder servo fail. I haven't been as lucky...

Originally Posted by wyo69cowboy

Not sure on longevity of a single rudder servo for everyone, but top pilots like Jase Dussia have been using single rudder servo on 120cc planes for a while now. I personally ran a Savox 2230 on my 120cc plane for 160+ flights/29+hours before I dumb-thumbed it. Transferred all of those servos (6 Savox 1270 & the 2230) to my 120" TBM, and have another 60 flights on that. That same 2230 is still going strong on the rudder of the TBM, with little slop or any other issues

Modern high quality digital servos last a LONG time. 100 flights is nothing.

I have a set of Hitec 5945s that I have been flying for 12 years (yes that's right over a decade) in the same airframe. Its an infreq. flow plane - probably 300-500 flights. On the second gear set right now.

Brushless servos last even longer I have a couple sets of Futaba BLS on helicopters with 200ish flights each, and I have a buddy who put 1200 flights (over 400 hours) airtime on a set of BLS255 heli servos before retiring them just because he wanted a change - they still worked like new on the original gearsets!!