Flap servo problems
 

Hey,

Just assembling my first plane with proper flaps and am having a bit of travel. The flaps require two servos, one in each side of the wing, joined together by a y-lead. When i lower the flaps, they go like ailerons, one up, one down. I can't really rotate the servo around 180 because of the design.
What happens if, on one servo, i change the positive and negative wires around on the servo lead? Does is work like a normal brushed motor, ie. it will rotate the opposite way??

Any help will be great!!:D

RE: Flap servo problems
 

No, switching those wires will not work. To rewire the servo you have to open it up and rewire the drive motor. This major surgery and should be avoided unless you're 100% sure of what you are doing. You have a few options here. Can you change the position of the pushrod so that it's on the same side of the servo for each flap? If you can this will fix your problem. Second option is to purchase a reversing Y-harness. This will cause the 2 servos to move opposite of each other. The third option is to mix the two servos together in your radio if it is capable of doing so. Of the three the best bet is going to be changing the pushrod.

Hope this helps

Ken

RE: Flap servo problems
 

as always Ken is correct

RE: Flap servo problems
 

You could also use a standard servo on one side and a "reverse" version on the other like Hangar 9 does in their F-22 trainer. They use JSP20050 AND JSP20050R servos.

RE: Flap servo problems
 

Different brands of servos are said by some to rotate in different directions. Anybody know the differences for sure?

If you're using the same brand throughout, the usual practice is to have the two aileron servo arms both point out or both point in, and to have the servo arms on the two flap servos both point either right or point left.

Changing one of the flap servo arms to point the other way should only be as hard as moving the location of the flap horn on one flap. And pulling the servo arm off and putting it back 180degrees.

RE: Flap servo problems
 

and if the horn is not moveable two 45* bends in the linkage should move the linkage over enough to use the servo arm on the correct side.

RE: Flap servo problems
 

One flap horn or the other should be movable. Unless the flaps are only as wide as the horns.

RE: Flap servo problems
 

I know that standard JR Sport servos turn the opposite of Futaba / Hitec / Cirrus But unless you just happen to have one laying around, and you can't change the position of the pushrod, the cheaper way would be a reversing "Y" harness.