[Rockyjs]

Does anyone have a solution to improving the response of the electric aileron trim on a RV8? On my friends, the electric aileron trim is inadequate. The system needs almost full servo throw before it has any effect which is very slow. With the springs detached the control column rotates freely, but the systems mechanical advantage needs improvement. I have been experimenting with clamping a small horn on the bottom of the control column slightly forward of the pushrod to gain a better mechanical advantage to bias the ailerons. Perhaps retrofitting to a manual trim is a possibility? Any ideas greatly appreciated. Thanks

 

[Andy Hill]

Rocky...

During our build we fitted a manual aileron trim. We didn't like the system, and the "spring loading" of the aileron control etc. In the final assembly we therefore omitted it - and have never missed it...

I am curious as to the need for aileron trim in a tandem? Once you've got any "heavy wing" corrected - then surely there is no need, unless you run the fuel very asymetrically for some reason

Andy & Ellie Hill
RV-8 G-HILZ

 

[decathlon737]

My electric aileron trim is installed per Van's instructions and works surprisingly well. I can run either tank down to a few gallons with the other one full and have plenty of trim to compensate. Might try to free up the control system and linkages, make sure everything is very free and not binding.

 

[rvbuilder2002]

Rocky...

During our build we fitted a manual aileron trim. We didn't like the system, and the "spring loading" of the aileron control etc. In the final assembly we therefore omitted it - and have never missed it...

I am curious as to the need for aileron trim in a tandem? Once you've got any "heavy wing" corrected - then surely there is no need, unless you run the fuel very asymetrically for some reason

Andy & Ellie Hill
RV-8 G-HILZ

The varying weights of occupants in the cockpit are the minor reason for having aileron trim regardless of what RV model you are flying. The primary reason is for fuel imbalance. Particularly at teh beginning of a flight with full tanks. All of teh fuel you initially burn off from a tank that is full comes from the very outboard end of the tank because of the dihedral angle. This has the most roll moment and only takes a few gallons to make a noticeable trim change. If you change tanks every couple gallons (every fifteen minutes) it is probably not an issue. I personally make my first switch at 30 minutes and then every hour there after. This makes me never have more than a 30 minute difference between tanks (about four gallons) buy it is still more than enough to cause an anoying roll trim imbalance.

BTW, if flying over rough terain (mountains, etc.) I make my tank switches when I am within gliding distance of an airport, highway, etc. for extra safety margin, and will delay a switch sometimes for tthis reason. This makes aileron trim even more valuable.

 

[rvbuilder2002]

Does anyone have a solution to improving the response of the electric aileron trim on a RV8? On my friends, the electric aileron trim is inadequate. The system needs almost full servo throw before it has any effect which is very slow. With the springs detached the control column rotates freely, but the systems mechanical advantage needs improvement. I have been experimenting with clamping a small horn on the bottom of the control column slightly forward of the pushrod to gain a better mechanical advantage to bias the ailerons. Perhaps retrofitting to a manual trim is a possibility? Any ideas greatly appreciated. Thanks

The system works fine if you get the roll trim properly adjusted before connecting the springs, and you install the springs with them pretensioned enough.
Many builders are afraid to pretension the springs enough for fear it will make the ailerons feel too heavy. It wont. The feedback force from the ailerons is still higher than the springs and they will not be noticed in flight. I have done lots of flight testing on RV's with the springs disconnected (to get the roll trim adjusted) and then connected the springs. After one flight you can't even tell there is a difference.