32-07: Flap Motor Brackets - Modification

Page 32-07 has us trim the flap motor mounting brackets. Since i am going with an alternate flap motor, the stock brackets will not place the motor mount holes in the correct locations (the alternate flap motor is 1.5" longer).  

Van's announced in previous months that they would be releasing some alternate flap mount parts which matches up with the new style of flap motor (and to look out for OP-65). Since Van's is having some issues (fingers crossed, touch wood), i decided to go ahead and modify my flap motor mounting brackets to fit the new flap motor. I may or may not proceed with riveting these into the airframe - will wait until i really have to install them. 

The modifications are detailed in the PH Aviation Flap Motor Instructions, and i followed these. 

The plans call for 1" x 1" x .063" angle - however i did not have any of this in stock. Not sure why, but i had 6' of 1" x 1" x 0.125" angle (twice as thick). Since the flap motor mounts between the brackets, the thickness will not affect the geometry - but i will need a longer bolt. 

I started by marking our and drilling 4 x #40 holes into one of the two flap mounting brackets, where the rivets will go to attach the angles. 

These were match drilled from one bracket to the other using a flat backrivet plate to make sure they are in exactly the same spots.

The plans call for AD4 rivets, so i made sure i had 1/4" of edge distance from the holes on one side...

..and on the other, that the tails of the rivets would clear the vertical part of the angles.

These holes were then match drilled into one of the angles..

..and i marked where the flap motor mount was supposed to be according to the instructions. 

I then checked this spot against the original hole - it needed to be 1.5" shorter, and it came out perfect. I then drilled a #40 hole at this location.

Then all the holes were transferred to the other angle.

Initial trim of the mounting brackets.

The brackets were then clecod together and placed into the airframe to measure the distance between the new bracket mounting faces.

These were installed with no shims, to measure how thick the shims needed to be.

The brackets, with no shims, are 0.8020 apart. 

This is the EXACT same width as the mounting boss on the flap motor. But i need to mount it with washers, to act as bearing surfaces when it rotates...

So i measured some thin and thick AD5 washers, and found the thin ones were 0.032" thick.. 

..and the thick ones were 0.063" thick. 

I happened to have some flap bracket parts left over which were were close to the same thickness as one thick AD5 washer. So i used these to make 2 shims to go between the flap angles and the flap mounting brackets.

On the -14 you get extra flap brackets - as they ship the same parts package as the -10. 

Test fit with the modified brackets, angles and shims

I checked the clearance to make sure the flap motor had enough travel to extend the flaps. 

As i suspected, the called out AD5-13 bolt is too short - as i have added 0.125" of thickness to this stackup. 

The hole measures as 1+3/16"

So i will need an AD5-15 bolt. 

All these parts have been set aside for priming, and i will rivet these flap brackets together when i get to the next session. I will not install them in the aeroplane until the last minute - in case Van's releases a better solution. 

Edit: With the Chapter 11 going on at Van's, i assumed that it would be a loooooong wait for OP-65 to be released, so i went ahead and installed these into the aircraft

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