Warbird40

My Feedback: (24)

I have a 68" Dragon Lady plane that has a 1 piece wing with a single servo in the middle and torque rods (same set up as trainers). I would like to know if there is a difference in performance in regards to the following:
1) Dual servos installed side by side in the middle (one for each torque rod)
2) One servo on EACH side of the wing installed towards the middle of each wing half

I am asking because the wings are already glued together and it would be difficult to cut a channel thru the foam for the servo wires, so I am leaning towards two servos side by side (since I am not happy with the single high torque servo in the middle. Any tips? Thanks

Best regards,
Ed

j.duncker

My Feedback: (2)

I would stick with a single high torque servo. It will easily handle the loads involved as the ailerons are not very big and it does not fly at high speeds.

I suppose you could put two side by side but it is just added complications, one will do fine.

invertmast

My Feedback: (23)

+1

Allot of the stuff now a days is overly complex IMO. A single servo is plenty on models such as this

Warbird40

My Feedback: (24)

Thanks, I will stick to the single servo.

Best regards,
Ed

Steve Percifield

My Feedback: (14)

Just for reinforcement, another that agrees with the single servo, and also, especially, the comment about a lot of things being overly complex. KISS..
steve

JohnBuckner

My Feedback: (1)

Good Plan Ed, Let me explain why. The primary reason for dual servo in the wing type of set ups we now have that is almost universal. This of course was not the case no all that long ago and the common setups were aileron torque rods to what were called strip ailerons which are not all that common now either.

The chief disadvantage of aileron torque rod actuated ailerons is it is very difficult to avoid looseness in the bering surfaces of the torque rod itself. What happen due to careless construction and the fact that the natural rocking action near both ends when torque is applied. both ends of the torque rod will wiggle and even get quite loose. This was increditably common and did in effect odd flight control and even be a contributor to flutter.

The is a way to do it that completely avoids the problem but that was not easy to do and time consuming. That technique involved no using any berings on the rods at all but an open channel was dug in the trailing edge The rod greased up and laid in the channel which was then filled with a mixture of epoxie and saw dust with a paper dam at each end. when cured the rods would release with a snap and form there on out and the result was a very smooth action with absolutely no wiggling at the ends and resulting wet noodle control response that was a result from that.

That being said just adding another servo in the middle did not get rid of this problem at all and that is why there is no point to it.

John

JohnBuckner

My Feedback: (1)

Good Plan Ed, Let me explain why. The primary reason for dual servo in the wing type of set ups we now have that is almost universal. This of course was not the case no all that long ago and the common setups were aileron torque rods to what were called strip ailerons which are not all that common now either.

The chief disadvantage of aileron torque rod actuated ailerons is it is very difficult to avoid looseness in the bering surfaces of the torque rod itself. What happen due to careless construction and the fact that the natural rocking action near both ends when torque is applied. both ends of the torque rod will wiggle and even get quite loose. This was increditably common and did in effect odd flight control and even be a contributor to flutter.

The is a way to do it that completely avoids the problem but that was not easy to do and time consuming. That technique involved not using any berings on the rods at all but an open channel was dug in the trailing edge The rod greased up and laid in the channel which was then filled with a mixture of epoxie and saw dust with a paper dam at each end. when cured the rods would release with a snap and form there on out and the result was a very smooth action with absolutely no wiggling at the ends and the resulting wet noodle control response that was a result from that.

That being said just adding another servo in the middle did not get rid of this problem at all and that is why there is no point to it.

John

Warbird40

My Feedback: (24)

Thank you John for the detailed explanation.

Best regards,
Ed

da Rock

Another big disadvantage to the torque rods was the fact they got in the way of hinges. Way back, we often made out own hinges by gluing alternating strips of cloth from one side of the wing or stabilizer to the other side of the surface. You'd glue a strip to the wing, then the next strip to the other side of the wing, etc. Each one would stick halfway out beyond the TE giving something to glue to the surface when you got to that step. When the glue was dry, you'd wrap the free ends around the TE and position the aileron against the wing. Gluing the free half of the strips down to the aileron without slack gave you a sealed hinge line, no slop, and hinging that had zero load and massive strength. It would also work around torque rods perfectly.

Nowadays, torque rods cause a major problem when we try to use todays most popular hinges: CA, pinned flats and hinge pins. The torque rod is in the way of anything that has to stick into the surface it's glued to.

BTW, way back we also had sewed hinging. That works around torque rods too. But today most everything is ARF. Zig-zag strips and sewed hinges aren't something you're going to see on an ARF. Or on any recent designs. So we won't be seeing torque rods unless they are short ones. And short ones are a poor choice for other reasons than hinging.

jester_s1

Just because I'm curious, why aren't you happy with the single servo setup on the Dragon Lady, Warbird40?

Warbird40

My Feedback: (24)

Rolls are not a fast as I would like, but then again it could be due to the dihedral's wing design of the airframe and not the single servo (I am new to flying, only 8 months. So I am still learning a lot)
Thank you to all of you who have helped me out and given me advise.

Best regards,
Edwin

Villa

Hi Warbird40
Ever since I saw that a plane can be controlled with just one aileron, I have favored using two aileron servos for increased reliability.