I want to know if there is a way to reverse one servo using one "Y" harness

There are reversing Ys, some report problems with them,

Better off investing in a servo programmer and use digital servos

Good luck

Another alternative method is to simply use one Futaba servo and one Hitec servo of similar type and performance. Since they are reversed by factory default. While I would not do this on ailerons but for dedicated flaps it works well and yes I have done this a number of times successfully.

John

many options,,
here's another http://www.horizonhobby.com/products...system-JRPA900

Matchbox is a good bet.

Reversing Y harnesses have been known to cause issues in some 2.4 installations.

The easiest way of course is to set them up that way in a radio that deals with it or mount the linkage on the other side of the servo if thats possible.

Only certain servos are programmable so if you go that route, make sure you get programmable servos from Hitec

Don't use a "Y" reverser . All good alternatives stated so far. I just open the servo and re-solder it to reverse direction. For me that is the easiest and cleanest way. If you are not good at soldering then don't try it.

Did you put the control horn on opposite sides of the servo? Or are you just in the planning phase?
with ailerons you want the control horn hooked to the servo arm through the push rod on opposite sides
of the servo. But for flaps you want the control horn through the push rod to the servo arm on the same side of
servo. So if you're having different travel (one up the other down) a simple fix would be to move the control horn over, then you can have the servo arm on the same side of the srvo

Don't underspec your flap servos. If you have one partially blow back while the other stays out you have a roll inducing situation.

Ask me how I know this.

Thanks fellas I was able to turn the servo around and flip it over to get the control arm the same distance from the horn. Now it moves the flap down like the other side! All is well. I've learned a lot in this exchange.