Roll & Pitch Trim????

[Phantom30]

This question is for -12 drivers w/auto pilots. I'm trying to understand functions... I see the control stick has a push-to-talk switch on top. And I've seen discussions about adding roll trim.

My question is...if you get a multi-function (military type) control stick w/4-way china hat that was typical for trim control. Can not the auto-pilot roll control servo and pitch servo be "step" controlled to effect roll and pitch adjustment for changing load/fuel burn conditions.

Hope this isn't a dumb question, but I haven't recieved the complete plans as I'm just finishing my fuse...

 

[Mich48041]

Unfortunately the servos are for autopilot use only and do not function as trim controls. In fact, sometimes the RV-12 gets so far out of pitch trim that it is difficult for the autopilot servo to move the horizontal stabilator. In that case, the Dynon indicates to the pilot that a trim tab adjustment is required. Some builders have put a pitch trim switch on the control stick to make it convenient to push. But that switch is connected to the Ray Allen servo, not an autopilot servo. The pilot can operate the pitch and roll functions of the autopilot separately. The autopilot roll servo not only keeps the wings level, but also keeps the plane heading in the right direction. I have used the autopilot extensively on long cross countries. Not only does it take you where you want to go, but you are not worn out when you get there. I sometimes shut the pitch mode off when flying under scattered clouds because the clouds cause up and down drafts that the autopilot constantly fights. I let the plane go up and down with the drafts and it all evens out over time with slight trim or power adjustments.
Joe Gores

 

[Driftdown]

. . . " I sometimes shut the pitch mode off when flying under scattered clouds because the clouds cause up and down drafts that the autopilot constantly fights. I let the plane go up and down with the drafts and it all evens out over time with slight trim or power adjustments." . . .

That is a cool feature.
Had not heard that before.
Thanks.

 

[RFSchaller]

Ric,

Here's the aileron trim tab.

http://i40.tinypic.com/102rx4h.jpg

http://i43.tinypic.com/2m7fp.jpg

Rich

 

[Paris12Man]

Trim tab

Rich, do you recall what thickness of aluminum you used? Also, do you notice any change in slow flight with flaps down with the trim tab installed?
Thanks
Steve

 

[RFSchaller]

Steve,

I used .032 which is pretty stiff. .025 would be plenty thick enough. One of he reasons I used so many rivets was because it takes a fair amount of force to adjust the tabs. I drilled a row of 1/8" holes at the desired bend line. Overall I'm happy with them and haven't had to readjust them in over a year. They don't seem to have any impact on flap performance.

Rich