Monthly Archives: October 2016

I had to take a week off building to do some work. Prior to that, I spent a fair bit of time on the mid fuselage skins making doublers for a pair of UHF antennae, and doublers and mounting points for the A/C condenser. That’s right, this RV-10 is going to carry around an air conditioning system.

I made doublers for a pair of CI-122 UHF antennae, positioning them in the second outboard bay left/right under each side of the rear seat ribs, a commonly used place in the RV-10 world.

Then came the time consuming part. The A/C condenser is mounted in a scoop. The standard attachment method specified by Airflow Systems is to use Rivnuts – because the installation instructions are written for an already completed aircraft. Since I’m slow-building the fuselage, I can take the slow route and use platenuts and doublers. This is quite a bit of extra work, and does turn the bottom skin into a piece of swiss cheese – but the end result is much stronger and cleaner than the rivnuts. All of the doublers and shims weighed in at 408 grams – so I’ve added 0.9 pounds to the airframe.

With this work done, I finished match drilling the skins, disassembled everything, de-burred and dimpled the skins, de-burred, dimpled and/or countersank the mid fuse ribs and spars. The skins and doublers are ready for priming. I don’t really want to prime the large F-1076 skin with my mini-gun, so I’ve ordered a regular spray gun – need one to do the interior painting within a month or two anyway. I’m going to put the skins aside until that arrives, and start on the firewall / forward fuse.

This week I’ve moved on through the infamous section 26 of the build manual, match drilling the outer ribs, rear set and baggage area ribs, de-burring, dimpling, priming and finally riveting them in place to make up the mid fuselage skeleton. This section of the build manual is infamous not only because it misses out several necessary steps that, if not done now, are very difficult to correct later, but also because Van’s have never revised the instructions. Various builders have documented what extra steps to do, I researched this and came up with the following list, to be added to the steps on page 26-5.

• Dimple the #40 holes in the F1015A outer ribs
• Dimple the #40 holes in the inter-costal ribs that mate with the F1015A ribs
• There are three #30 holes in the side skins that are not present in the F1018 ribs. Cleco the F1018 ribs to the side skins now, final drill these holes, and dimple them with a 120 degree dimple set (they will eventually receive CS4-4 rivets).

To do the above, I laid out the F1015A and F1018 ribs, lay the side skin on top and cleco’d the ribs in place. I match drilled all of the #40 holes between them (except for the holes not to be dimpled), and used the skin as a drill guide for the three #30 holes in the F1018 rib. I then de-burred and dimpled the ribs. You need a 3/8″ female 3/32″ dimple die because of how close the holes are to the flange of the rib, and the thickness of the rib making the flange corner quite rounded.

I did look at one builder’s log where he had mistakenly placed the vertical flange of one of the outer ribs on the outside of the corresponding riser, rather than the inside. I recall wondering how anyone could make such a silly mistake, given the obvious detent in the rib. After riveting the left side F1018 outer rib in place, I stood back and looked at it – and couldn’t believe I had just made the same mistake! It turns out to be quite easy to engage the auto-pilot while riveting and overlook something like this. Easy to correct with just three rivet drillouts, but it would have been hard to fix later on when there were more things in the way.

After completing the mid fuse skeleton, I needed to stand it up on something to hang the bottom skins, which overlap the bulkhead by a few inches to overlap the forward spar. I lay the cradle I made for the horizontal stabilizer on its side (not being used right now because the HS is bolted onto the empennage), braced it to some workbench legs, and it made a perfect work position to clamp the mid fuse assembly to while hanging the bottom skins.

Next step is to match drill the bottom skins. While these are in a convenient work position I’ll also drill the necessary holes to mount a couple of antennae, and the A/C condenser.

Over the past week I started on the Fuselage. I’ve decided to hold off on closing up the wings for now. I have some primer that is going to expire in a few months, and given what it co$ts the best thing to do is use it up asap. I also need to figure out various system issues over the next month or so because I have to order various things that will take 6 months to get here by boat. Charging ahead with the fuse is the best way to come to terms with what I need to do.

The fuse build starts with various bulkheads, which are all fairly easy to work through. I went ahead with some of the mid fuse ribs, in order to completely fill the spray booth up. After priming everything, it didn’t take too many hours to rivet together the various bulkheads, and finally the inboard and outboard seat ribs.

Next job is to de-burr and match drill a bunch of ribs that join the rear bulkheads up, extending through the rear baggage area.