I have been thinking about how to prime the elevators for the past few days. The plans call for the stiffeners to be riveted to the skins well in advance of any other drilling, deburring and riveting associated with the elevator skeleton. I want some corrosion protection but I don’t want to apply two coats due to weight considerations, and also to avoid the rivet holes becoming two small to pass rivets through from applying two coats of primer. I decided to use some self-etching primer in a can and only spray the one side of the stiffeners that will be in contact with the skin, and the area on the skins where the stiffeners will cover. This will allow me to get on with building the rest of the elevators and provide some corrosion protection for the stiffener/skin union. I can then use my 2-pack primer to apply a top coat to everything. Here’s a shot of one of the skins with self-etching primer applied.
I then primed the “skin side” of each stiffener and clecoed them onto the skins.
As I was clecoing the trim servo hatch doubler I started to wonder how the nut plates were going to be installed. I hadn’t touched any of the nut plate holes yet and the thought of having to drill, dimple and debur whilst the doubler was riveted to the elevator skin didn’t appeal to me. So I double checked the plans and there was a 1-liner I had missed in the instructions that called for the nut plate holes to be dimpled and deburred. Oops. Better now than after the rivets.
The plans provide little detail in what to do for the doubler. I guess at this stage of the build they are relying on you more to figure out what you have to do, rather than spelling it out for you in detail like they did for the HS. So here is what I did. I had to think for a minute to figure out the correct way to dimple the nut plate holes. You want the doubler and nut plate rivets to offer a flush surface to the servo hatch. First I used my #6 die set and dimpled the large bolt holes for the nut plates.
I then dimpled the nut plate rivet holes and taped -3-3.5 flush rivets into position and riveted the nut plates onto the doubler. You can see how the nut plates stick out from the doubler. I don’t think this is a big deal.
I then clecoed the doubler back onto the skin and checked for fit. All good.
I then got into riveting the trim servo doubler and the stiffeners to the skins.
I didn’t have too many problems back riveting and was making good progress. I think I started to get complacent at this stage. That’s when this happened…
This is what happens when you don’t have the back plate correctly lined up behind the rivet when you try and set it. The skin has been creased by the edge of the back plate. Damn. I managed to flatten this out a bit by carefully using the rivet gun but I couldn’t remove it completely. It’s only small and it’s on the under side of the elevator so it shouldn’t be easily seen when on the tarmac. I’ll show it to my TC at the next visit. Hopefully he’ll tell me it’s ok. Not much I could do about it so “build on”. Here are both elevator skins with stiffeners riveted on.
The plans then called for work to begin on the elevator skeletons. I picked out the spars and then spent 10 minutes trying to find the hinge doubler plates. I forgot that they came with the hardware so they weren’t with all my other parts. I eventually found them and clecoed and match drilled them to the spars.
I then picked out the ribs and started to prepare them. I managed to edge prep the main ribs but I started getting tired at this point. It was getting late so I called it a night.
Total build time – 5.5 hrs.
As I was updating this blog I realised that I had passed the 100 build hour mark. I am guessing about 1200 hours for this build so this is about 8% complete. Almost double figures…