I started riveting the tail cone. Various builders before me seem to have used a back riveting procedure to rivet most of the tail cone, so I thought I’d give that a try. I assembled all of the bulk heads per the plan procedures, but left the top of several bulk heads cleco’d for now, just in case that helps later on. All went well with the bottom skin and stiffeners, until I started riveting the left F-1029 bell crank rib assembly into place. After setting three rivets, I had a look over the remainder and was shocked to find a missing dimple. I checked every part multiple times during and after dimpling, but clearly missed this one. Luckily I only set three rivets before noticing the problem; no choice but to drill them out so I can deal with the missing dimple.
I decided to prime the tail cone skins before the mountain of other parts. Get the easy part done first. The NACA vent holes, and the holes for the static ports, were treated with an Alodine pen and masked over, since the pro-seal used for these parts will achieve a better bond directly to the scuffed Alclad. The weather was a bit cold – 12 degrees C, so I mixed the primer and let the pots sit in the house family room – where there’s a wood burning stove – for the induction time. The primer went down OK, just took a bit longer to dry.
Next will be the “long” parts (stiffeners etc.) together with small parts to fill up the booth, followed by the remainder of the tail cone parts.
I must be the world’s slowest de-burr-er because it has taken an entire week to pull apart the tail cone, de-burr everything, dimple all the parts and skins as necessary, and do a few other jobs ahead of time. There always seemed to be more things to do. In any case, it’s all done now, ready for priming.
I did take care of some extras along the way:
A doubler for the aft bottom skin, to allow mounting a NAV antenna under the tail. This is a common location, but putting in the doubler after the tail cone is assembled is “hard”. Doing it now, it is easy.
Van’s instructions for installing tail light wiring in OP37-16 has you drill through the entire stack up consisting of the VS spar and F-1012 bulkhead stackup, which includes the F-1012E tie-down bar. I didn’t want to deal with making such a hole straight with a hand drill, or de-burring such a thing, so I pre-drilled through the F-1012 stack-up, slightly over-sized. That only leaves a hole in the VS spar, which will be easy to match up.
Many builders add aft NACA vents to feed vented air into an overhead console. Australian summers are hot, and plenty of vented air is a good thing. I chose to cut the vent holes now rather than after the tail cone is assembled. There’s a bit of a pucker factor involved in smashing holes in a perfectly good skin, and I trialed a few methods on a test piece before settling on an ancient jig saw I had in the workshop. The holes turned out well. I scuffed the area where the vents will be pro-sealed to the inside skin. These will be Alodine’d with a pen after etching, and masked off so they’re not primed.
Since I’ll have to set up the long etch bath to do the F-1047 stiffeners, I went ahead and made up the push rod assembly. That way I can etch the (73 inch) push rod tube while the bath is set up, and prime the inside of the tube per Van’s recommendations.
I’ve started tail cone disassembly. Removed and de-burred the top two skins and the top three J stiffeners. Match drilled the rear seat belt anchors into the longerons. I drilled the 1/4 inch holes required for the SafeAir1 static ports, using a reamer. I’m going to proseal them on, with no rivets. Have to remember to leave a circular area on the inside skin un-primed and well scuffed, for the proseal to adhere to.
I built a temporary support cradle on wheels for the tail cone, mostly out of scrap from one of the Van’s shipping crates (no picture). I’ve grown used to being able to easily move things around in the workshop (everything else is on wheels), and once the tail cone is sitting around here on its own I thought it might as well also be turned into a little vehicle.
That leaves the remainder of the tail cone to disassemble, de-burr, scuff and prime. That will be a long and boring job.