Tailcone Brackets, disassembly and somewhat major issue

Tailcone Brackets

An item I left off on my previous post was having to create several brackets and do a bit of match drilling with the aft deck into the longerons and other pieces.  Making the brackets are fairly painless, just follow the measurements and trim accordingly.  The drilling however is a bit of a different story, maybe should have used a drill press or have someone QA my measurements prior to drilling but I messed up a set of holes on the F-1011D bracket.  In particular the holes that go into the longerons, but will get to that in a second.

See how the top bracket holes don't like up to the picture

Starting out with clamps in place and starting from the middle you start match drilling all the #30s in the order called out in the plans.  I was so focused on spacing the longerons correctly I overlooked that I had completely missed the center line on the F-1011D bracket.  Even looking at the picture now it sticks out like a sore thumb, probably because I know it's there.

After that I started the disassembly of the tailcone.  This is a methodical process making sure everything is labeled correctly and that no hole is left untouched or any pieces with jagged edges or otherwise unfinished looking edges.

Major Issue

While deburring the longerons I noticed that instead of holes where the F-1011D bracket is there were little notches instead.  I instantly knew where I went wrong, remeasured and found the problem.  

Solution #1 - Remake the bracket, replace the doubler, aft deck, both longerons and cleco the plane back together to match drill everything accordingly.  Time and cost aside this might lead to some enlarged holes or other issues such as fit with match drilling something twice which may or may not line up exactly as it was before.

Solution #2 - Call Vans!

Well that's only part of the solution and it's what I did.  Builder support requested I take some pictures and send it to them, so he can review it with their engineers.  The good news as I see it is the notch is only an 1/8 inch in... will be filled by a bolt and there's a lot of material in terms of doublers that will also help reinforce the longerons in that area.  Another positive is there's quite a bit of extra room below the longerons and in the bracket area that can be used to come up with some new methods to ensure proper strength in this area.

Shows the doubler and how the longerons line up.  Didn't include the Aft plate.

I will wait for Vans suggestion but here are some thoughts I have.  Always looking for the positive felt this would be a good time to work through some ideas.

This is actually upside down... 

Idea #1 - This involves making a fitted bracket which would be the thickness of the longerons to be sandwiched between the Aftdeck/doubler/bracket group and a new made bracket which extends beyond covering the entire bottom of the longerons.  This would allow the screws for the #12 to drive though the notches and be secured by the bottom piece which is all riveted to the aftdeck, doubler, ect.

Idea #2 - Same concept as above but involves instead trying to capture some forward rivet holes as well.  The concept is the same, first bracket is the thickness of the longerons.  The paper in the below picture represents a smaller triangle bracket which would capture not only the Aftdeck/doubler/bracket group but the first forward hole as well.  Could even throw in an extra rivet in the middle there.

Idea #3 - To me this one makes the most sense but may be a bit overkill... then again I don't mind overbuilding things, especially untested things.  This is similar to #2 but uses a much larger triangle bracket.  This bracket would capture the #12 hole, two Aftdeck/doubler/bracket group rivet holes, and two rivet holes on the longerons forward of the notch.  Could also add an extra rivet hole into the aft deck to keep the middle-sandwiched piece in line.








Will be continuing one with the next few pages of the plans until I hear back from Vans on a preferred method. They may have something completely different in mind and will defiantly post about the fix when I get it.