My question is about useing two servos for your ailerons ( one on each) I know you use Y hook up. What does this do for the plane different then useing one servo running but ailerons? When useing the Y does it make one aileron move at a time or do they both still move? Just wondering why and how this helps my flying.. Thanks.

It really depends on the plane in my opinion. Many of them do just fine with a single aileron servo. I suppose the dual servos give a little quicker, more precise movement. You tend to see it more in aerobatic airplanes. Also, if you have big plane or just one with big control surfaces it may take one servo per aileron to move them.

The Y hookup still moves both ailerons just like a single servo would. You can also use two separate receiver channels for ailerons on more advanced radios. This allows you to really fine tune the movement and differential. It's probably needless complication on most simple sport models though. A single servo or dual servos with a Y-harness is best for those in my opinion.

A big advantage (well, big depending on who you talk to - big advantage for aerobatics anyway) is that when you have dual aileron servos, each control arm is mounted more towards the center of the aileron. This allows for less deflection in the aileron.

If you have one servo for both ailerons, the control horn is most likely mounted close to the fuselage on each aileron. You are applying force at this point, while the air resistance is applying force over the rest of the aileron in the opposite direction. What happens is that the aileron actually twists.

If the control horn is mounted in the center of the aileron, as with dual aileron servos, there is less opportunity for the aileron to bend.

Also, as said above, there response is faster with a center mounted control horn.

Many of the planes today have dual aileron servos on them and many will tell you that it improves performance. But that's not always true. In fact, one of the best flying planes EVER made uses only a single aileron servo mounted in the center of the wing. And it doesn't suffer performance at all. If you're interested in what plane I am talking about I'm referring to the Great Planes Ultra Sport, both 40 and 60 size. Back when planes like this were designed servos were very expensive and using two servos for ailerons were unheard of. These days servos are cheap and it's easy to have 2 aileron servos. So if it's so easy to use two aileron servos why did I even mention this? To point out that it's not necessarily an improvement in performance that would dictate 2 servos, because if the plane is designed right one servo will suffice. Now with that said, there are good reasons to have 2 servos as opposed to one. A few worth mentioning. Servo failure. With 2 servos a blown servo on one aileron will not kill the plane as you can still land with just one aileron. With 1 servo there are usually a torque rod setup which might result in flexing of the aileron in extreme manuevers such as 3D flying, where the short pushrods from a servo on each wing results in less flex. Also, the shorter pushrods and the geometry of the servo in the wing gives the control surface more power to move the control surface. These are just a few of the reasons why.

To answer the second part of your question. With a Y-harness both servos receive the same instructions at the same time, therefore they will both move in the same direction. Refer to the attached diagram to see what I am talking about here.

Hope this helps

Ken

thanks guys for the info. that does help me with my questions.

there is another advantage to having dual aileron servos...my 4 Star 60 in a decending L/H turn for a low, high speed pass...as I add power just before level off I hear a buzz and see my R/H aileron fluttering...throttle back to idle and do a climbing L/H turn to kill airspeed and set up for an emergency landing....the aircraft did not have the roll authority it should have had..but a nice landing was made and taxi to the pits was uneventful...investagation revealed a stripped R/H aileron servo.....the L/H aileron servo was ok..and that was enough to get me on the ground in one piece...I don't think that at that time I had the skill to get her back using just rudder.
So you see a dual aileron servo saved my Four Star 60 for more flights