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Empennage

Dimpling HS and VS parts

With the fabrication work on the VS essentially done, I thought I had better dimple everything in preparation for priming. So last night I started out by setting up my pneumatic squeezer in a vice. A few builder’s websites have shown this setup and I must admit it’s quite handy for dimpling the skeleton. I could dimple almost all holes with this arrangement except for a couple on the long spar channel pieces. I found the spars sometimes ran into my shed wall so I couldn’t do a couple on some ends.

I dimpled all of the skeleton flange holes in both the HS and VS. A few of the tip ribs were a little tight to get in but with a little coaxing I got them done. Once I finished doing as many holes as I could, I took the squeezer out of the vice and clamped the spar channels on the bench. I then dimpled the few holes I couldn’t reach holding the pneumatic squeezer.

With the skeletons dimpled, I moved onto the skins. I didn’t want to spent the rest of my precious build hours that night to make a stand by my DRDT2. So I improvised using a saw horse, some spare planks of wood and a couple of clamps. I set these pieces up as a temporary stand for the DRDT2 and placed it between my work bench and my mobile tool bench.

It wasn’t what I would call “pretty”, but it did the job. I started dimpling the skins. This was a little awkward, particularly when trying to dimple the holes close to the skin’s leading edge but the alclad flexes fairly well. Working slowly and carefully, I managed to dimple the VS skin and half of one of the HS skins. It was getting late so I called it a night and planned to finish off the skins the next day.

After a flying lesson in the morning (on track for my GA licence in about 4 weeks … yay!) I snuck into the shed to finish off dimpling the skins. All was going well…

… until …
WTF IS THAT?!?!?!?!?!

A “spot” on the inside scuffed skin of the VS caught my eye. Upon closer inspection it appears to be a small triangular tear in the skin. I flipped the skin over and it appears something small and sharp has dented the skin. It’s very small, but it’s a HOLE IN MY SKIN! Damn … gutted. I have no idea how this has happened. I scuffed this last weekend and it wasn’t there then.

My initial thoughts involved “skin replacement”. I believe little tears like this end up as big tears that can cause catastrophic airframe failure if left. I emailed my SAAA Technical Councillor for advice and when looking for a beer. Damn, damn, damn. As I pondered over said icy cold beverage, I thought that I might be able to fix this by drilling a hole in the skin (thereby removing the tear) and placing a rivet in it. This would resolve the tear issue without having a massive patch, or having to replace the skin. The more I thought about it the more I liked the idea. I would just have a rivet on it’s own in a weird location on the VS, but you probably wouldn’t notice it unless you looked for it. I thought I could even drill a matching rivet on the other side so that it “matched”. I started to feel a bit better and I’ll confirm if my idea is suitable.

Build time over the 2 days was 3 hours – 2 hours on the HS and 1 hr on the VS.

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About gstrack

Husband and father of 2. Control & Instrumentation Engineer. Flying nut. Gadget geek.

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