Monday, December 17, 2018

Elevator Trim Tab Assembly

 Started tonight by riveting the elevator trim tab control horns to the trim tabs.  I riveted the aft five holes before riveting the spar to make it easier to get to them.  I used the longeron yoke for all of these.  Just have to be careful on alignment.

 Here they are before I riveted the spar.

 And the other side....
 Next I riveted the spar.  Due to the geometry of the yoke and sets, I had to slide the yoke on from the end.  One trim tab was easier than the other due to the right and left hand nature of it all and because I am right handed.

 Here is one all riveted.  Rinse and repeat for the other side.

 This thing is worth its weight in gold for jobs like this.  I taped up the yoke to help minimize the carnage to the primer.

 Next it was time to mix some black death to glue in the ribs.  Yes!  That is too much proseal!  I ended up wasting a ton of it!
 Buttered up the foam ribs and inserted them in their new homes.  Not too big of a mess as long as you keep using two pairs of gloves and change the top layer often.

 All done and cleco'ed together to cure for a bit.

Final step tonight was to install the pop rivets on each end of the trim tabs.  Easy peasy!

So for these trim tabs I got lazy and cheated and used rattle can primer.  The same Duplicolor Self Etching stuff that I used a bunch of on the RV-7.  Well it appears that they have changed the formula a bit because this stuff today dries to a powdery green finish instead of an OD green.  No big deal but different.  Also I had forgotten how easy it is to scratch this stuff.  The AKZO is far superior as far as toughness goes.  I likely won't be doing that again unless it is just a small simple part that won't get much abuse.  The trim tabs get a beating while in final assembly so I made a bad choice.

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