Bi-plane aileron set-up with 4 servos? brain teaser.
 

Which set-up is correct...and why?
The scenario is an average bi-plane, using (4) servos for aileron control...one servo per aileron, and driving those four servos from two separate channels in the receiver. The question is this...

Set-up A: One rx channel drives both left and right aileron servos on the top wing, and the other rx channel drives both left and right aileron servos on the bottom wing.

Set-up B: One rx channel drives both left side aileron servos, that is, left aileron on the top wing, and left aileron on the bottom wing. The other rx channel drives both right side servos, right aileron in the top wing and the right aileron in the bottom wing.

I guess either set-up works, but some flyers have very strong beliefs about which one is better. And your thoughts are...?

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

G'Day Mate,
Setup B is the right one to use, You would need a Y lead for the servos, & Flapperon setting on your TX.
Setup A won't work.

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

I agree with alan 0899, although if you are using a tx & rx that have atleast 8 channels then you can do it without using the y's & set either the top wing servo's or the bottom wing servo's as a slave to the other. The advantage to doing it this way is that you can make adj. to each servo seperately with your tx. It takes a little more time & thought to do it this way, but it makes it more convenient when you start trying to get all your ailerons perfectly aligned.

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

I'd have to go with plan "B", also. Most radio mixes are set up for dual servos to operate left and right ailerons, so "Y-ing" the two right servos to one channel (1) and the two left servos to another channel (7) would make radio setup easier.

But why use 4 servos? Put two servos in one wing, and make a mechanical linkage from bottom to top aileron on each side. Super Stearman, WACO, Sopwith Pup, SE-5a all are done this way, plus many others. Cheaper, less battery power used and less weight out in the wings, too.

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

Sorry to disagree, but setup "A" is the correct way to go.

Reason:

IF you have a failure, one wing on each side will stop working, leaving you with one wing working on each side

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

Set up B is the right one. It gives you diff and expo. Also if you want you can have spoilers. As far as worrying about failures. You can still fly with only one side working. Dennis

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

One aileron will adequately bank and level a plane. The model that was flown Transatlantic the other year only had one aileron, to save battery power. I still vote plan B, and Tx mixes are all set up to support that method; but my other thoughts on just using 2 servos is what I'd do.

RE: Bi-plane aileron set-up with 4 servos? brain teaser.
 

Set up "B" is the correct answer too, due to the fact that if you use set up "A", you have two wings that you can't trim together. In otherwords, placing too much right trim in the upper wing will only have to be off set with too much left trim on the bottom wing in order for it to fly level. This creates excessive drag and yaw. The plane only needs one aileron out of the four, or one set on one side to fly it and get it down safely.

Keep the dirty side down!! Take Care! Dan