Trim Tab - Part 5

The tab clevis attachment requires a stiffener - a three [3] sided tray was folded with two sides trimmed to match the rib profile, The front edge was match drilled using the front edge of the tab. Two [2] angles were folded to tie the side webs to the front of the tab skin. All rivets used on the lower skin were 1/8'' counter sunk to allow the faring not to foul in operation on a dome rivet.

  

Tab clevis reinforcing plate

Stiffener was cut from the scrap material from the trim tab folding. 

The cover plate was slotted to allow the full operation of the MAC trim motor. It had to be wide enough to allow the clevis to clear the cover.

Trim motor cover

The final assembly with the faring cover for the tab and motor fitted. The cover for the motor was the prototype for the rear light of the rudder. This was machined from a 3D model in China but was not suitable for the task but has found a new home.

The inboard rib had a 1/2'' hole drilled on the same center as one of the lighting holes in the attachment plate for the shaft that connects both elevators. The loom for the trim motor exits through this opening to connect with a six [6] pin plug located under the rudder fin. Access  will be gained by removing the fuselage fairing. The hinge pivot was secured using a scrap piece of hinge pop riveted to the rib.

The threaded rod has a crank to allow connection to the tab clevis attachment to allow full stroke of the motor without fouling the tab spar.

Inboard rib details

Final task is to attached the tab clevis and test the assembly and at this time no problems are foreseen - famous last words !