Back To The Grind

Decent progress this last week, I guess. I'm finding that it's harder to gauge how far things are coming along with fiberglass work, because it's much more of a subjective art form than it is a concrete, step-by-step process. I think I'm much more of a step-by-step kinda guy.

We've continued with the A-pillars in the cabin cover, filling and sanding, filling and sanding. Complex curves are tough, but we've found out that using the right sanding block is the key to it. I made a sanding block out of a piece of 2" PVC pipe that is about 6" long, and hold it at about a 45-degree angle to the curve of the A-pillar. In this way, the roughness of the filler slowly sands away to become smooth with the natural curvature of the pillar.

The A-pillars, maybe about halfway done sanding and filling

We also final-attached the vent ducting to the cabin cover yesterday. This was kind of a benchmark step, since it had to be done before we can design and layup the overhead console itself, which will cover most of the ducting you can see now. It will also enable me to continue with the switch pod, and get everything to play nicely together. Lastly, we can also start on the B-pillar closeouts, which will be a similar process to what we're doing with the A-pillars, although hopefully not as difficult.

The vent ducting final-attached to the cabin cover. You can also see the spray foam making the general (initial) shape for the B-pillar closeouts

That's pretty much it on the fiberglassing front. In other news, I've done a bit more work in the tailcone area as well. I've attached the master and crossover solenoids to the battery mount, and re-made the yaw damper servo mount out of a slightly bigger sheet of aluminum, allowing me to mount the Garmin GDL-39R receiver next to the yaw damper servo.

Yaw damper servo (right bottom), Pitch servo (right top), GDL-39R (center), crossover solenoid (left)

Battery tray and master solenoid (left), crossover solenoid (right)

It came out pretty good so far! I'm excited to start wiring this stuff up. I did make my first RG400 BNC cable too, connecting the GDL39R to the TED transponder antenna located in the free area just aft of the elevator bellcrank. I watched a youtube video from SteinAir found at this link: https://www.youtube.com/watch?v=xPyLeBIcf9c, and it was really not a whole lot different than crimping standard household RG6 cable, other than using a slightly different crimper and the need to crimp a pin to the center conductor. The principle is pretty much the same though. I look forward to making the 10-20 more BNC cables necessary for the rest of the airplane!

Lastly, I had a question from a fellow RV-10 builder about the battery tray that I modified, so I'll describe what and why I did stray from the original Vans design F-1035 Battery mount.

The F-1035 battery mount is designed for a single Concorde RG-25XC battery, which has a footprint of 7.5" x 5". Many folks prefer to use an Odyssey PC925, which has a footprint of 7.05" x 6.64". Lastly, folks that run a dual-battery system typically install two Odyssey PC680's, each with a footprint of 7.15" x 3". Since I'm planning on having a "true dual" electrical system on this airplane, I'd like to go with the last option. However, I wanted to design a battery tray that would still have some flexibility in its design, in case someday I want to go back to a single battery setup, or maybe even move one of the two batteries up front for CG purposes.

After tossing around this idea for a bit, I decided to modify the factory mount to be 7-1/4" wide and 7-1/2" long, with provisions to attach a small 3/4-wide aluminum angle divider in the center (pictured above) and/or at the back. In this way, I can install two PC680's with a 3/4" gap in the middle and a 3/4" barrier in the back; a single PC925 with a 3/4" barrier in the back; or a RG-25XC in the original lengthwise configuration. There is an additional 3/8" nutplate installed between the two original 3/8" nutplates, so that I can attach a third hold-down bolt in that location to help keep everything secured and properly spaced.

The tray was modified by cutting off the side walls and taking some extra pieces of aluminum sheet and 1/8" angle pieces to make some extensions to "patch" into the existing part. You can see the two double rows of rivets in the photo above where the seam is. All in all, I'm very happy with how it has turned out, however I haven't yet actually installed any batteries, so the jury is still out as to whether or not it will work as I expect!

Hopefully that helps answer the question about the battery tray. Next post will likely be from back in fiberglassing hell! :-)