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

 

Door Trimming, Cowl Fasteners

We noticed that the right (pilot side) door was slightly warped, so we removed the Lexan and bent the frame a little bit to get it back into position.  Then we trimmed the clear Lexan sheet for the right door so that it fit nicely against the fuselage.

We did a little bit more (epoxy) finishing work on the cowling, then drilled for 1/4 turn Skybolt fasteners on all the cowling pieces. The fastener bases were riveted in place, and the pins for the mating pieces were attached with clips.  We had a couple strange issues with hole placement that we ended up fixing by filling and redrilling a few of the fastener holes.  Hours: 16

Skybolt fasteners riveted in place

All cowling pieces attached with Skybolt fasteners

Seats, cowling, fuel site tube

 We replaced the lower cushion foam on the seats with memory foam to make them more comfortable (the factory seats are a common complaint among builders).  3 layers of foam were cut to shape, glued together, and then stuffed into the existing fabric seat covers.  This foam does weigh more than the original foam, but figured that the extra comfort was worth the weight penalty.

New (colorful) seat cushion foam

Some epoxy with flock was added around the fuel door to close up a gap near the hinge and make it look a bit nicer.

Work done around the fuel door

Quite a bit of sanding and filling work (using 3M lightweight filler) was done on all three cowl pieces to shape and smooth them out.  Some lightweight filler was also added around the NACA duct to smooth the transition areas.

Filler work around the NACA duct

Ed getting ready to add some lightweight filler

A protective guard around the fuel site tube was completed, painted black, and installed.  The site tube has a striped pattern behind it to help visualize the fuel level.  Refraction causes the pattern to change when fuel is in the tube.  We also have an electronic fuel bingo sensor that indicates when fuel is low.  This was tested and verified to be working, but we will do some testing before setting the level at which it triggers.

Fuel site tube with stripe pattern.

We also started some work on the right (passenger) door.  The lexan sheets that form the doors were trimmed to fit better against the fuselage.  We still need to do the same for the pilot side door.  Hours: 21

Michael trimming a door panel