I need some input guys

[CVA59]

I'm trying to get my Rebel ready to maiden. However, I cannot get my ailerons even. I can't get them set to the same amount of throw in both directions. I have played with the sub trims, and linkages until I cannot stand it anymore. In my 25 years plus of building and flying, I have NEVER EVER had this kind of situation before. Not matter how or what I adjust, one direction always has more or less throw than the other. Can someone please give me suggestions here? I guess I am too dumb to figure it out on my own. I'm pretty sure it is just something in the programming I just don;t know what.

[CZ Flyer]

Eliminate the obvious? Are both linkages in the same holes? Only other possibility I can think of is maybe they installed 2 different servos by mistake.

[CVA59]

Eliminate the obvious? Are both linkages in the same holes? Only other possibility I can think of is maybe they installed 2 different servos by mistake.

Yes, both linkages are in the same hole, the servos appear to be the same visually. I have done everything but remove the servos as I was hoping to not have to do that yet. It's almost like the servo arms are clocked differently from one another. However, with the adjustments I have done to the linkages and sub-trims I should be able to get that to a degree but I can't. I can center one servo arm and the other will be off by an 1/8 or so. I may just have to remove it and reset the control arm. I can get the ailerons to even at what would be level flight position but the throws are off. When I sub-trim the the ailerons to a level flight position, the port side servo arm is slightly forward of neutral. Starboard side servo arm is straight up and down. Instead of being 10mm up and down. I am something like 10mm up and 5mm down or vice versa.

I will try to get some pics tonight.

[xviper]

Yes, both linkages are in the same hole, the servos appear to be the same visually. I have done everything but remove the servos as I was hoping to not have to do that yet. It's almost like the servo arms are clocked differently from one another. However, with the adjustments I have done to the linkages and sub-trims I should be able to get that to a degree but I can't. I can center one servo arm and the other will be off by an 1/8 or so. I may just have to remove it and reset the control arm. I can get the ailerons to even at what would be level flight position but the throws are off. When I sub-trim the the ailerons to a level flight position, the port side servo arm is slightly forward of neutral. Starboard side servo arm is straight up and down. Instead of being 10mm up and down. I am something like 10mm up and 5mm down or vice versa.

I will try to get some pics tonight.

It would seem that one of the servo arms is in need of being "clocked" one or two teeth to be the same as the other. Sometimes, this is not possible as moving it one tooth is too much, however, with a difference of 5mm from up to down, one arm may be quite a bit off from center. To determine if the servo is at 90 degrees when at mid-point, you may have to do a test with a servo tester that has a center position. Then you will know for sure.
Oh, you didn't inadvertantly program in some differential, did you?

[Robert Belluomini]

Can you plug each servo into a seperate pirt on the rx?

[CVA59]

It would seem that one of the servo arms is in need of being "clocked" one or two teeth to be the same as the other. Sometimes, this is not possible as moving it one tooth is too much, however, with a difference of 5mm from up to down, one arm may be quite a bit off from center. To determine if the servo is at 90 degrees when at mid-point, you may have to do a test with a servo tester that has a center position. Then you will know for sure.
Oh, you didn't inadvertantly program in some differential, did you?

No, all I have done in play around with the linkage adjustments & sub-trims. I will see about getting a servo tester and try that. Otherwise, I really don't know what else to do with this thing. I can't fly it with the ailerons being so much out of adjustment.

[CVA59]

Can you plug each servo into a seperate pirt on the rx?

Yes, I can. What's your idea on that?

[meadowhay]

It would seem that one of the servo arms is in need of being "clocked" one or two teeth to be the same as the other. Sometimes, this is not possible as moving it one tooth is too much, however, with a difference of 5mm from up to down, one arm may be quite a bit off from center. To determine if the servo is at 90 degrees when at mid-point, you may have to do a test with a servo tester that has a center position. Then you will know for sure.
Oh, you didn't inadvertantly program in some differential, did you?

I'd definitely check that both servo arms are in the same position at neutral and adjust as required. It should be pretty easy to do as the servos are held in place by the rather neat plastic box.
Use a servo tester if you have one with both servos plugged in at the same time,either using the multiple output on the tester of by using Y lead.
You should be able to get both arms to within half a gnat's of each other which will make a big difference to the overall geometry of the linkages.
Alternatively, as already suggested you can use 2 separate receiver outputs and trim each aileron independently for centre point and end points.

[CVA59]

I'd definitely check that both servo arms are in the same position at neutral and adjust as required. It should be pretty easy to do as the servos are held in place by the rather neat plastic box.
Use a servo tester if you have one with both servos plugged in at the same time,either using the multiple output on the tester of by using Y lead.
You should be able to get both arms to within half a gnat's of each other which will make a big difference to the overall geometry of the linkages.
Alternatively, as already suggested you can use 2 separate receiver outputs and trim each aileron independently for centre point and end points.

Will do, thanks very much everyone. I will try these suggestions. However, I've never used a separate output like you have described. I am running a 6-channel setup. Can you give me some more info on that? I have always used a "Y" splitter for my ailerons.

[xviper]

Using a "Y" is just one channel. You need an extra channel and tell the TX that you have "2 AIL" plane type. However, putting them on separate channels won't help you if the arm is not on the servo at 90 degrees when centered. All that does is allow you a better chance to sub-trim out one or both arms so they are both at 90 degrees but this doesn't make them at mid-point in their overall travel.
One thing that has not been mentioned. You say the rod is on the same hole on the arm on each servo but is the other end of the arm on the same hole at the aileron? Did you exercise the control surface BEFORE you attached the rod? Sometimes hinges can be extremely stiff going one way as opposed to the other. They need to be worked. Also check for obstruction of the control surface travel. This should be evident when you "work" them by hand.

[CVA59]

Using a "Y" is just one channel. You need an extra channel and tell the TX that you have "2 AIL" plane type. However, putting them on separate channels won't help you if the arm is not on the servo at 90 degrees when centered. All that does is allow you a better chance to sub-trim out one or both arms so they are both at 90 degrees but this doesn't make them at mid-point in their overall travel.
One thing that has not been mentioned. You say the rod is on the same hole on the arm on each servo but is the other end of the arm on the same hole at the aileron? Did you exercise the control surface BEFORE you attached the rod? Sometimes hinges can be extremely stiff going one way as opposed to the other. They need to be worked. Also check for obstruction of the control surface travel. This should be evident when you "work" them by hand.

Gotcha! Yes, I checked and the linkage is in the correct hole son each end. I did disconnect everything and worked the ailerons back and forth and they seem to move freely without any friction. When I get home today I will remove the servos, compare the arm locations with them side by side and see where things wind up. I will set everything on my TX back to zero settings first. Hopefully it is just one of the arms being clocked wrong on the servo is all that's wrong.

This is a post from another flyer who had the same issues:

I just had the same "issue". Unfortunately there was no perfect fix, I ended up using the threaded vertical adjusters as a way to get them to throw as even as possible. Going down vertical on the right side elev helped increase the ratio and bring it closer to the left side but they are still a mm or 2 off when pushed to max up/down throw.

I flew it twice without any noticed effects just yesterday. this was my first edf jet.

Only way i can see it being fixed is to revise the linkage design from the servo arm to the vertical rod that is pulls evenly for both (the z-bend end at servo actually is part of the issue as it moves one linkage forward an extra mm or 2 at full throw)

its a cheap edf so i'll just fly it as is unless I see any ill effects come up.

[fhhuber]

Is the servo arm parallel to the control horn at neutral? If not, you have managed to set up mechanical differential throw.

[CVA59]

Is the servo arm parallel to the control horn at neutral? If not, you have managed to set up mechanical differential throw.

This is essentially what I am dealing with while in neutral with zero trim & zero sub trim.

[xviper]

This is essentially what I am dealing with while in neutral with zero trim & zero sub trim.

Remove arm from port side, reposition it to 90 degrees. Re-adjust the rod for level AIL. That ought to resolve things.

[fhhuber]

This is essentially what I am dealing with while in neutral with zero trim & zero sub trim.

Pretty close to what I expected frm the description of the problem.

Note: Before adjusting the servo arm. Check that the sub trim and trim of the radio are centered. Accumulation of these adjustments over a few models, without clearing model memory for a new airplane can lead to this issue appearing to be mechanically miss-installed servo arm when its really a computer radio programming error.

[CVA59]

So, I played around with it some more last night. I removed the servos, removed the arms, cleared my sub-trims and dual rates all back to zero. With the servos as close to neutral as the radio system will get them, this is what I'm left with. Because of the servo splines being what they, It still won't center like the other one as viper mentioned above. I do believe it will work ok now but that's the most I can hope for at this point. They were off a bit more than what I would have expected which is a bit disappointing. I had to change the linkage lengths a good deal to make the ailerons true up with the trailing edge. I will be looking at getting a servo tester at some point to set all my servos in the future.

[Jblitz118]

1 center servo on remote,2 unscrew linkege from servo and put it back on alighned,3 physically adjust the control rod length until it's flush with your aleron

[meadowhay]

1 center servo on remote,2 unscrew linkege from servo and put it back on alighned,3 physically adjust the control rod length until it's flush with your aleron

+1 for this.
Get the arms mechanically aligned as best you can (which you have) then use sub-trim to perfect it before adjusting the linkages which will be almost identical at this point.
Then Voila! Set the end points and you're there.
Happy flying

[CVA59]

Thanks guys, I did this exact process and they are MUCH better now, however one servo arm is still clocked slightly forward. I don't feel that would cause any problems, I just wanted them both the same. I will maiden it tomorrow if it doesn't rain and report back on how she flew. Thanks guys!

[CVA59]

I flew the Rebel today for the first time. First time I have ever flown an EDF and the first time in 8 years I have flown anything. The winds were 8-12 and that proved to be very tough on this plane. I did get in 4 flights (4 packs) successfully. She flew GREAT in between wind gusts and after I get her trimmed out. I am very pleased with this little plane. Will be going out again tomorrow morning for 4 more flights.