Finishing the Flap Actuator. One Flap Drilled, One to Go

2/1 – 2.5 hours.

So last time I was pondering what material to use for the final piece of the flap actuator – and I had persuaded myself to use a scrap of 1/8″ 6061 angle instead of the 1/16″ called for in the plans.  It would add an ounce.

This morning, I remembered an entire drawer of surplus aircraft mounting brackets.  I couldn’t bring myself to recycle these a few years ago when I was cleaning out the shop, and I forgot them in a cabinet I seldom open.  They are all shapes and sizes, and a huge quantity.  This pair is 2024-T4 and 1/16th inch thick!

Brackets before shaping into the part shown below on the plans.  Just a few minutes with the band saw and sander, and I have a left and right set – ready to go to work – and better than the plans call for.

All the actuator parts set in position on the flap.  I extended the angle about 3/4 inch past what is called for in the plans in order to catch the next rivet.  The entire actuator assembly is built in 3 pieces so that it can be EXACTLY fitted to the flap – but order is very important.

Here is another view of the 3 parts.  Thus far the only joint is clecoed between the angle and the plate.

Clamping the angle and plate in position against the spar.  The plate now is held in position, not touching any parts.  The angle is carefully drilled and clecoed to the spar, as the 3 outermost holes also go through the front of the inboard rib.

Here is the angle set in position as well.  It transfers the movement of the flap handle to the spar and the inboard flap rib.  Notice how the three layers (skin, rib, and angle) tend to separate when there are no clecos in position.

I clamped the angle against the plate to ensure a firm fit.  Now, the bottom skin/rib flange holes can be extended onto the bottom of the angle.  I loosened the clamp and reclamped between adding clecos to ensure that alignment is true as the aforementioned gap is closed.

Now with the angle clecoed in place along the rib bottom, I can draw in and drill the holes that mount the angle to the plate.  The fit is perfect because it was match drilled in position.

Here is the right flap, completely drilled and clecoed.  All that remains is to dissemble, debur, dimple, prime, and rivet.  And now I get to start over again on the left flap.  I expect it to go quicker, however.  THis is because I have already grappled with the order and because I already built the actuator bracket.

This brings me almost to the place I would be if I had bought a modern pre-drilled kit.  If you count your time as worth anything, don’t buy an old kit that wasn’t pre-drilled.  I am about 10 hours into the flap.  If I charged myself the $50 per hour for A&P work that I charge other people, I’d have another $500 in just this flap.  And don’t forget – KW did the flap spars!  However, I am not upset.  I knew what I was getting into when I signed up for this job – and I am actually having A blast.  Right now, I can’t wait to get at it each day.  I am sure that will wear off, however.

Here we go again!  Spar, ribs, and bottom skin drilled and clecoed before the end of today’s work.  I probably will not be adding many more photos until I come to something new.


Leave a Reply

Your email address will not be published. Required fields are marked *