can I assume that one channel can operate more than one servo?

yes rich, one channel can operate 2 servos via a Y harness - however note that they will rotate simultaneously AND in the same direction, so if you need one to rotate in the OPPOSITE direction. you will need a Y with one side reversed OR have one servo reversed (more complicated)

hope this helps

helps a lot, thanks.... trying to visualize all this prior to purchasing my first plane....

knowledge is good

most Ys I think are reversed.

One channel can operate more than 2 servos, with like a billion Y harnesses.

Note battery will be dead very soon with tons of servos.

Most Y harnesses are not reversing type. You need to specifically ask for, or order (or pick out) a reversing type Y. And yes, you can gang multiple servos together with additional Y's, but there really isn't any point.

If you need to run say four servos (as in two servo for each elevator half), then you should be thinking of buying a small piece of electronics designed for this. JR's has one called a "Match Box" that allows up to four servos plugged into it, with each servo's end point and throw to be individually adjusted so that all throws and end points 'match'. Futaba also has one, but I don't recall the name.

These devices also allow additional battery packs to be used to drive trhe servos so you don't overload the receiver pack.
Dennis-

Does it really need to be reversed?
Just connect the pushrod on the opposite servo arm hole.

For dual aileron servos it does not have to be reversed, but there are times when reversing one servo is desirable, or even necessary. That's when you need a reversing "Y"

Yep.

Just curious, when would it be necessary to have it reversed that cannot be done by putting it on the opposite hole? Maybe I have never been in that scenario.

There is always a "preferable" way to mount a servo. If both the servo arm and the control horn are the same length, and they are set up so that a clockwise servo movement creates a clockwise control-arm movment, then there is a proportional, and linear relationship between the two servos. i.e. 10 degree servo arm movement makes 10 degree control arm movement.

If the servo moves clockwise, and the control arm moves anti clockwise, then when the servo movements at the center of its travel will have either more or less influence than the same degree of movement at the ends of its travel. This can be thought of as mechanical "exponential".

So, depending on the behaviour you want, then the side that the control horn is on may have a significant impact on control surface behaviour.

Also, sometimes it is just pragmatic, or cosmetic that you want the servo horn on one side rather than the other.

Think about it.

gus

"4 channels and 5 servos" usually implies that the plane uses dual aileron servos i.e. one servo in each wing instead of a central servo controlling both ailerons.

It is usual to have both servos operating in the same direction with the control arms and pushrod setup acting in a mirror image. e.g. the control arms mounted on the outside of the servos (away from the fuse on each side). This way, one servo will be pushing and the other pulling, making the ailerons move in opposite directions which is what you want, and is similar to having the control rods attached to the opposite sides of a single servo.

A simple Y harness just splits the power and signal to two servos. Wouldn't a reversing Y harness need a circuit to reverse the signal? Or does it just reverse the polarity of the power?

An alternative to the Y harness is mixing on the radio where you use a flap channel for the second servo and set the wing up as flapperons. When you move the aileron stick the servos will move in the same direction and when you adjust the flaps the servos will move in opposite directions (unless you manage to change this with radio programming).

Just for those who might decide to get picky, "4 channel and 5 servos" could also apply so a simple twin where the control surfaces only require one servo for each channel but two servos are required for the engines.....