So here is the catch up post from my previous one that was 2.5 months ago.
I fabricated some mounts for my newly purchased landing lights. It wasn’t too hard and I think they will work for now and maybe longer. I purchased a simple wig-wag circuit from Amazon to provide some recognition. It worked well, but the way I wired them to use a single DPST switch, I was not getting the expected behavior when in wig-wag mode. The problem was solved by adding some diodes to the wiring. Once that was done, everything worked great. I’m slowly learning how all of this electricity works.
I rebuilt my parking brake with new seals. Upon inspection of the internals, there were some serious burs in the passageway that houses the “valve” of the parking brake. After filing those away and putting some new seals on, it seems to be working as advertised with no leaks.
I finished the skylight over a few days. This was a pretty intense operation with all the holes that needed locating and drilling. I made a mistake when I was cutting the skylight strips that sandwich the skylight with the skylight ribs, so I had to order a new one from RANS. Surprisingly, the strip I ordered was larger. It was double the width and almost three times the thickness (1″ wide and 0.050″ thickness if I remember correctly). Since I didn’t want to have a lopsided plane, myself and another builder got our hands on some Al sheet of a similar thickness and cut some new strips for the skylight. Since I had already drilled the other ones, the new ones were mostly a quick transfer operation. I also trimmed my skylight short of the tabs on the aft side of the skylight where it is supposed to capture tabs that are welded to the fuselage. I really didn’t like myself at that point, but the fix proved to be very simple. The skylight is approximately 1/8″, so I made two strips of Al to sandwich the sky
light and then bought a 1/8″ thick Al bar from McMaster to fill the gap between the two strips and act as the connection to the fuselage. It turned out really nice and I’m pleased with it.
Once I painted everything for the skylight and windshield, I set off on installing it. This was pretty straight forward, but time consuming with all of the rivets and clekos required. My one fiasco involved my attempts to put a silicone fillet on the edges of the parts to avoid getting water into the cockpit. It is a skill I haven’t quite mastered yet.
The big annoyance in this process was the brass washers that go on the inside of the windshield so it doesn’t have a rivet right next to it. The correct way would have been to place these rivets in there locations with a dab of silicone prior to attaching the windshield to the plane. If you don’t do that, then be prepared for an annoying hour or more trying to get washers to stay on rivets while you pull them. I had to drill out three rivets that had washers pop off during installation. The fiberglass windshield hold down strip does not tolerate much drilling.
The boot cowl went on without much fuss. I would recommend super gluing any washers you will use for spacers on the tabs of the fuselage to make the process go a bit smoother. Something I haven’t done yet, but will soon is put a bead of silicone in the crevice that is created in between the firewall and boot cowl to better seal off the inside of the cabin.
With the windshield and boot cowl installed, the engine was ready to be started! I made preparations by trimming the spinner and locating the holes in the backing plate for attaching the spinner. My one word of advice here is to be very particular about lining up the spinner and the backing plate. Any offset will affect the spacing/interference with the prop hub. I ended up with some slightly over sized openings in the spinner, but it doesn’t look too bad at all.
Due to an error by me while reading the prop instructions, we set the pitch of the prop to what we thought was 17 degrees. My prop is a 75″ Whirlwind and the starting point from WW is 15 degrees. On initial run of the engine and a subsequent full power test, I was only able to produce 4300 RPM. Rotax wants to see 5000-5200 as a static RPM, so I was a ways off. We leveled the plane and then set it to 15 deg. That proved to be too flat and I called off the static runup when I hit the engine’s max rated RPM of 5800. It took us 3 more tries of fine tuning the prop to get a static RPM of just below 5300 which we considered good enough.
I had a small issue with my mag switch wiring, that was discovered during the engine start day, but it was a simple fix. I am using the ACS ignition switch and there are two terminals labeled the same, but do not do the same thing apparently.
We did a quick carb balance, set the idle, and everything was going well. It was exciting to get to this point as I had been thinking about it for years.
Once the engine was started I set off on all the tasks I had left before I could have the plane inspected. I went ahead and set a temporary date with the DAR so that would be scheduled and I would give myself a more concrete timeline to get the plane finished.
This involved installing the wingtips and wing tip lights. I had a lot of trouble with screw holes not aligning even though it fit very well before I painted and installed them, so that was annoying. Maybe the paint was the culprit.
I trimmed and covered the remaining interior closeouts. I had to modify the closeout right behind the seats quite a bit to clear all of the wire/hoses/etc. that were passing through it. I used the same Sunbrella fabric that I had used on the baggage. This time I used a spray adhesive product from Loctite that worked tons better than the 3M Spray adhesive. Definitely recommend.
One of the very large tasks that I had left to do was fitting the cowling. From start to finish this took about 3 days of working the whole day. I would not do it with less than two people and just take your time. As hard as you work to get the cowling to fit close to the boot cowl, the receptacles and 1/4 fasteners are not a tight enough fit to keep the upper cowling from moving slightly away from the boot cowl. I did not paint the strips that the boot cowl attaches to and it looks bad. When I paint the cowling I will use a brush to touch up those strips and I think that will hide the gap very well. I had issues with the lower cowling hitting the radiator, so I had to trim the exit to be just forward of it. Consequently it sticks out a little below the cowling, but I didn’t like the though of the cowling sitting against the radiator. I also had interference where the forward inlet for the radiator was touching the engine mount tubes. I ended up clearancing the material away from the tubes. This all came to a new point when I installed the radiator duct and then the cowling came into contact with that, but I am leaving it for the time being. I don’t think there will be much movement there and it is a non-critical part.
I had some additional trimming in the inlets in front of the cylinders to clear the engine, but that was very straight forward.
I have the S-6 setup for my cowling and the molds didn’t seem to be the best. The lower cowling joggle at the inlets is angled outward so you have to fight with it to get the upper cowling on. The only solution is to trim the area down to make the angle somewhat better. The lower cowling is also not symmetrical which I think is a mold issue and not a design issue. Oh well, it will still fly. I have a carbon cowling and after working with a fiberglass cowling, the carbon seems much nicer to work with and it’s lighter. It also will lighten your savings, so that should be considered as well.
After getting the cowling finalized I did some final taxi testing to test out the handling of the airplane on the ground and see if I had any obvious cooling issues. Everything went well and all of my instruments seemed to be operating correctly and smoothly.
This gets us to the inspection which will be another post on its own and will include the flight test.
(100 hrs)
