Could you share the info you recieved from futaba. I'm still curios about the (40degrees) for these channels and (55 degrees) for the others.

BigNed,

I think I know the answer to your problem #1. It is due to the ailevator function. It is the servo in channel 8 that is slower than the one in 2, its purely a function of the mixing/programming software, which gets the signal info to channel 8 slightly later (on the order of milliseconds) than channel 2. All radio brands experience this. The same thing happens on mine, I have 9CAP and Hitec 605 servos on my UCD. The speed difference is clearly visible on the ground, but it never translates to an observable (rolling, etc.) effect in the air. I've learned to ignore it, even though I hate to see it. The only way to solve problem 1 is to use a reversing Y and have both servos in channel 2. Then there is no lag between the servos since they are driven by the same signal.

The other problems you speak of I do not have, sorry. If the endpoints match, and the centers match, all the in between deflections should match - everything is linear. I can't figure out why your problem would appear. You can't accidentally program expo into one channel of the mix and not the other, can you? I.e., channel 2 is linear and 8 has some expo? I don't think this is possible...

Hope this helps some, at least with #1,
Kurt

------------

Adding a link to a [link=http://www.rcuniverse.com/forum/m_392785/mpage_1/key_ailevator%252Cservo%252Cspeed/anchor/tm.htm#392785]related thread[/link] which addresses this issue.
Here is [link=http://www.rcuniverse.com/forum/m_1384561/mpage_1/key_ailevator%252Cservo%252Cspeed/anchor/tm.htm#1384561]another.[/link]

Rumple - Sorry dude but its not normal. My Airtronics Stylus dosen't do it. I have dual elevator servos on my Extra 300 and they track to perfection at the same speed. My elev. channels are 3 and 8 and i see no delay. I am running in PPM not PCM 1024 either.

Adrian, you may have faster servos which makes the lag tougher to see. This is a common problem, it is normal. Its easiest to see with slower servos, large control surfaces, and large deflections. In some cases you can't see it (milliseconds are pretty short). Look around and search RCU, there are many airing the same concerns.

Kurt

My Extra does use fast digital servos but I had a UCD 60 with 94102's (like Fut 3003's) and it was perfect too.

Sal,
Futaba said the 40 55% thing should NOT be a visible difference.

I think I found something, Im not sure what to make of it but none the less my servos are tracking perfectly together right now .

Heres what I did,
1. Fully charged batteries.
2. Made a note of where I had my up and down endpoint values set on both elevators.
3. Set the all the endpoints back to zero on elevator channels 2 and 6.
4. Gave full "up" input on the stick and started increasing the endpoint on one of the elevator channels.
I eased it up until the servo reached the point where it started chattering and backed off 2 clicks. Then I did the same thing on the other elevator till they lined up, fortunately the 2nd elevator never chattered before they matched up.

Heres what I ended up with for ep settings before and after
Channel 2
Before
up 65 down 60
After 49 down 44
Channel 6
before
up 100 down 100(?? I Dont get this, why are the 2 channels so different??)
after
up 100 down 100.

So I raised the settings on channel 2 back to 65 and 60 and the whole problem came back and I didnt gain anymore throw.
Went back to the 49 44 setting and everything is perfect and I have about 43 degrees of throw. I dont think the numbers matter, what matters is not having your EP set beyond what the hinges or servo/ servo linkage can give you.

Here is what I think.
I had the endpoint setting set way past where the elevator could actually travel and so it was getting to the mechanical limit of the servo before it reached the computer endpoint, which was also screwing up the expo. This threw the timing of the 2 separate elevators off bigtime.
Now that the elevator is only being asked to travel within its mechanical limits the computer is able to synchronize the ep and expo so that both surfaces move together. At least its working for me.

If you are having this problem try this, it worked for me.
First, if your centering is off, fix the linkage or subtrim to get the surfaces both neutral with the transmitter and receiver on.
1. Switch to high rate
2. Go to the EP function, Set your elevator EPs on zero, all 4 of them (2 on each side).
3. Pick elevator channel 2 or 6 give full up/down,, nothing should happen( zero endpoint)
4. start increasing the ep till the surface gets to the desired angle or mechanical limit. If you hit the mech limit back off a couple of clicks.
5. Go to the other channel and do the same thing. If the mechanical throw limit is less than the other channel then you will have to back off to satisfy the lesser mech throw limit of the 2 channels.
6. Do the same thing with down elevator.

I may be nuts, let me know what you think. Its working though,, go figure.

BigNed: That makes total sense. I follow what you did and that was the ticket if you ask me. Set both channels "up" EP's to match the lesser of the "up" mechanical limits. Set both channels "down" EP's to match the lesser of the "down" mechanical limits. Good troubleshooting dude.

This is starting to make me wonder if I have my flaperon mixing on channels 1 and 6 setup correctly on one of my planes (6EXA). It's common to use this mixing for ailerons when you have twin servos and don't want to use a "Y" cord. After reading this thread I will go back and see if my control throws are linear and equal.

Joe

Sure thing JoeAP,
I am new to all of this and I feel like a made a quantum leap in my understanding of the relationship between the radio programming and the control surface movement. I hope my problem doesnt come back. I may just have to throw m'self off the nearest bridge if it does!