Final Instillation Of WD-1215, WD-1214 & AP Roll Servo

The last remaining items left to complete the instillation of the flaperon control system is bolting together the left WD-1215 flaperon torque arm and left WD-1214 flaperon torque tube. The parts were installed and bolts torqued much the same as the right side with the exception that the autopilot servo also attaches onto the left WD-1215 flaperon torque arm. The roll autopilot servo pushrod assembly piggybacks on the mounting point for the flaperon pushrod … this requires using a longer mounting bolt. The AN3-10A bolt that normally attaches the flaperon pushrod onto the WD-1215 torque arm needs to be replaced with a longer AN3-14A bolt which is supplied with the autopilot kit. This bolt also receives a large washer which is supplied in the AP kit.

The AN3-10A bolt in my right hand normally secures the flaperon pushrod onto the WS-1215 torque arm … it will be replaced with a longer AN3-14A bolt with large washer in my left hand to accommodate the roll autopilot servo pushrod which can be seen sitting on top of the WS-1215 torque arm.

Builders installing the autopilot roll servo during the build or adding the servo to a completed RV-12 should be cognizant of how the bolts are installed. Many builders have installed the bolt heads on the outboard side of the WD-1215 torque arms (because it is easier) which is OK … until the AP roll servo is installed. With the AP roll servo installed, the bolts in the WD-1215 torque arms need to be installed from the inboard side of the torque arm or there can (and have been) interference issues. While installing the longer AN3-14A bolt a small issue was noticed … the plans only call for one AN960-10  washer under the nut but there seemed to be some of the bolt shaft just barely showing so I added a second AN960-10 washer just to make sure the nut would not bottom out on the threads.

Completed instillation of the flaperon control system including the autopilot roll servo. Take note of how the heads of the bolts securing the flaperon pushrods & roll servo pushrod are installed from the inboard side of the WD-1215 torque arms.