Oil Dipstick Rusting and Wing Fairing - Part 1

Posted Sep 18, 2026 1.5 hrs

By Fan Zhang

2 min read

TLDR

Investigated some rust from oil dipstick
Start on wing fairing installation

Details

Oil Dipstick Rust Mystery

I had a 10-minute engine run yesterday to set the throttle idle, and today when I inspected the oil dipstick, I saw what looks like rust on the top of the oil dipstick and some water dew on the stick.

I’m pretty sure the rust wasn’t there before I ran the engine esterday. So it formed overnight.

Since water is by-product of fuel combustion, I guess the tiny water droplets on the stick is not surprising. But I have never seen rust forming overnight like this on any other airplanes. I checked around the engine, and didn’t find corrosion or rust anywhere besides the oil dipstick..

I asked on Facebook builder’s group. One of the builders (Eric) said he has seen it on his airplane before and it wasn’t a big deal. Another builder (Rodrigo) suggested I might have to get the oil temperature higher to boil out all the water, which makes sense too.

From my inspection, the fact that the rust formed overnight and unevenly tells me there is some kind of defect on the oil dipstive itself.

I will keep monitoring the rust situation for the next few engine runs. If it still happens, I will just buy a new oil dipstick.

Wing Fairing

Installing the wing fairing is mostly tedious work to align things and drill holes, but not difficult. I spent about 1 hour on the right fairing and finished about 80% match drilling. It’s a loop: test fit, match dril, curse why it’s not perfect, then repeat.

One tricky point before drilling: the fairing is along side the joint of side fuselage skin and the bottom skin. On top of that there are a bunch of ribs and other important structural components near the edge of the fairing, so I had to be extremely careful planning where to drill. I have to avoid drilling into anything important.

To be continued next week. I expect the entire week next week will be spent drilling holes and installing rivnuts. If I haven’t mentioned I hate rivnuts before, I hate them!!