Originally Posted by Jaybird

Wonder if you have too much throw on those giant ailerons and it's acting as an air brake at high speed ? I know foamys will do that but never messed with it on the bigger planes. It would be easy to back off a few degrees and give it a shot.

I was thinking the same thing. I wonder the lentgh on his servo arms?

my carf weighed 24 # 7 oz on the nose with pipes

there are AMAZING

for those who doubt the flight loads at WOT causing blowback on this airframe.......let me show you something......My 3W yak would do a knife edge loop at mid throttle but when i would try to knife edge at high speed it acted mushy like i didnt have enough power on rudder. Now, i thought there was no freaking way that was the problem but my spotter was telling me it didnt look to him like the rudder was kicking over very much at all. changed my geometry by moving out a couple of holes on the servo tray arm and problem was solved. im posting a pic to illustrate why i said there was no fricking way it was blowback.........I WAS WRONG!!!!!

setup has been changed slightly from this photo.......using the giant 3W rudder arm on the tray and running a-123 instead of lipos. you get the idea though. blow back vs 4 futaba high torque digitals..

That's not a fair fight.

whats not a fair fight Pryor? explain

Originally Posted by planecajun

for those who doubt the flight loads at WOT causing blowback on this airframe.......let me show you something......My 3W yak would do a knife edge loop at mid throttle but when i would try to knife edge at high speed it acted mushy like i didnt have enough power on rudder. Now, i thought there was no freaking way that was the problem but my spotter was telling me it didnt look to him like the rudder was kicking over very much at all. changed my geometry by moving out a couple of holes on the servo tray arm and problem was solved. im posting a pic to illustrate why i said there was no fricking way it was blowback.........I WAS WRONG!!!!!

Did you move out on the servo arm or the control serface arm. If you moved out on the servo tiller arm you reduced the amount of torque but increased the amount of throw. If that's the case then chances aare you had too much expo in the rudder.

expo had nothing to do with it....... the pull-pull cables were in the only holes they could go to in the rudder bell crank. the servos were connected to the bellcrank around 1.5" on each side of center. i had more throw then i needed, but not enough torque. i moved the position that the servos were connected out away from center, improving my mechanical advantage but reducing my throw. problem solved. even if expo would have been an issue, with full control stick input, you get full surface deflection no matter how much expo youre running, see what im saying?
anyway, it was definitely blow back, and the problem was cured by moving the servo connection point.

For those who dont know, and might be reading......the following is the rc formula for mechanical advantage:

shorter the arm on servo the more power you have, the longer the arm on servo the more throw you have.
the opposite applies to the control horns.
shorter the control horn more throw you have, longer the control horn, more power you have.
setting up correctly is finding the happy medium between the 2 that produced optimum power at desired throw.

oh, forgot to say, thanks for the reply Scott. your input is appreciated.

Originally Posted by planecajun

oh, forgot to say, thanks for the reply Scott. your input is appreciated.

No problem. But you are saying you moved the connection point out on the servo side, which is how I understood it before. Your therory is right in your last post, but you still say you moved the connection point out. That would reduce torque and throw. Help me understand what I'm not getting.

ok.......let me see if i can draw a picture and post the picture. that would be the easiest way.

i didnt move the links out on the servo arms. those stayed the same. (there are actually no links between servos because its a cable setup. its the connection from the servos to the bellcrank. ill post a picture.

Originally Posted by planecajun

ok.......let me see if i can draw a picture and post the picture. that would be the easiest way.

i didnt move the links out on the servo arms. those stayed the same. (there are actually no links between servos because its a cable setup. its the connection from the servos to the bellcrank. ill post a picture.

Ok I understand now. I thought you did the pullies on the servo arms not the bellcrank.

Originally Posted by planecajun

whats not a fair fight Pryor? explain

That one went right over your head. " blow back vs 4 futaba high torque digitals "

Are you home or, on the rig?

ok heres the picture. you can see the dotted lines in the top drawing, that is the new location of the connecting point from servos to bellcrank. since its a cable type self adjusting tray, there is no linkage geometry to worry about. doesnt matter if all the servos throw together or different. only geometry that matters is from the bell crank to the rudder.

im still on the rig pryor. LOL its not hard to go over my head. i knew you were talking about that fight, but what i didnt know is which one you thought had the advantage.....the blow back or the digitals.