Engine test #2, more Cowl work, and misc

We had a run of nice weather, so decided to prep the plane for another ground run.  We bolted the propeller back on, carefully setting the pitch of each blade to keep them within 0.3 degrees of each other.  We decided to keep the cowling on for this test since we had just finished installing the Skybolt fasteners in them.

This time we ran the engine for a longer test period (about 15 minutes), and also ran up briefly at full power to verify the prop pitch.  At full power, our engine RPM needed to fall between 5100 and 5800 RPM to ensure the blade pitch is within limits and safe to fly (per guidance from our prop manufacturer, E-Props).  Ours came up to 5200, so it is good.  We may need to change the prop pitch a bit later once we get to the flight testing stage.  E-Props recommends pitching for 5500 RPM when in flight at full power.

Michael behind the controls for the 2nd engine test run

The test run went well, although we did uncover a few issues after looking everything over after the test run.  We found some drips down by the right brakes, and found two brake fittings that had drips and need to be addressed.  We also found a bit of fuel leaking around the fuel pressure sensor that we will fix.  This shows how important these early tests are as they help flush out these type of issues.  Some brake line compression fittings and a few new fuel hose fittings were ordered and will be installed once they arrive. 

We also did some additional work on the cowling to improve the surface finish.  This included adding a little more filler and sanding. The front ledge of the boot cowling was also trimmed back a bit (about an inch). We decided to shoot a light coat of primer on the three cowling pieces, as this can help to find remaining defects in fiberglass.  We did this outside since our paint booth is currently full of tools and parts.  Not sure why this works so well, but just this little coat of primer really did help highlight some of the remaining irregularities in the surface that we will now fix.  

Light coat of primer on the three cowling pieces

We also wanted to address the cockpit down tubes that are directly in front of the pilot and passenger.  We decided to wrap them with a matte black vinyl to hopefully help mitigate reflections on the windscreen. A 2" wide strip of vinyl perfectly went around the circumference of the two tubes. Hours: 21

Black matte vinyl added to down tubes