Today, I felt a bit scatterbrained. I just really couldn’t get any traction on any one task. I started by releasing the layup we did yesterday on the gear actuator cover. I then trimmed the part and sanded off all the fiberglass prickers I could find. Pity, you never find them all. The part is certainly functional, but lacks a symmetric or pleasing shape. We will need to do a few repairs to it as I caused a pretty big delimitation when I was releasing it. Right now, I see no reason to re-do the part since it is only a cover after all. Though it probably will be on a list of potential small projects to work on after the airplane is flying and we have a week of bad weather. (Or winter in MN)
Then I switched gears to wiring. I was going to work on the permanent power cable to the VPX system, when I realized I didn’t have the proper ring terminals. So I did one side of the wire, routed it, labeled it, and added the proper ring terminal to my shopping list. While I was working with “electron transmission devices,” (sounds more technical than wire, huh) I decided I would start to route the wiring for the seat heater. I got so far as to plug a wire int the VPX to supply power to the seat heater harness, and it was time for lunch.
After lunch, I decided to leave the wiring alone and try to get some epoxy curing on the oil cooler exit duct. I had to be done working by dinner time tonight. I figured I could get a layup done, and if it took longer than expected, I would simply get less time wiring. HA. It took me the rest of the day to simply make the form for the duct.
I started by figuring out the shape of the hole in the baffle that will allow the oil cooler exit air to dump overboard. This was determined by having a minimum flange width all around the duct to allow the duct and baffle to mount together as well as to allow a place to mount the baffle seal material.
Then I used that to make a couple blocks of blue foam fit between the oil cooler and this exit.
These blocks gave me a starting shape and location, at the oil cooler, and an end, at the baffle. Then I just had to make a smooth aerodynamic duct between the two… Simple right? Should be. But I made it more difficult than it had to be. Because I didn’t have a precise plan before I started cutting foam blocks, I ended up cutting away foam that should have been cut away. So I had to cobble pieces of foam back onto the form.
The problem is these pieces get to be pretty thin in certain spots as you sand them to the irregular shape that this duct requires. So these pieces are hard to hold in place. You can hold them with nails for a little while. Until you can’t sand past the nail and you can’t push them in any further because the foam is so thin. You can hold them with tape until the foam dust destroys the stick of the adhesive. You can hot glue them in place, but that doesn’t work well because it melts the foam and causes a low spot, and eventually breaks free. You can 5 minute epoxy them in place, but that takes, well, 10 minutes. You get the picture.
Suffice to say, it took a while, and was a mixture of shaping, then putting tape around the exterior to hold things in place. I even resorted to filling some of the low spots with Play-Dough to try to smooth out the duct. It is directing airflow after all. I keep kids play-dough on hand just for little things like that. It is cheap and actually works pretty well. Best thing is you can toss it when your layup is cured.
Anyways, it is now ready for a layup with just a bit more tape to protect the oil cooler and a flange on the baffle side. Maybe I can get it laid up before I go off to Phoenix.