Well, I have been nudged into keeping this blog going, and have done to the realization that if I attempt to catch the blog up on the cowl process, I will never get back to regular posting. The lower cowl method was the same as the upper cowl, with the exception of the air inlets and scoops. Rest assured I will add a page devoted to my cowl process at a later date, probably when I am bored in another hotel on a layover.
As is always the case, the AirVenture Cup race and Oshkosh refueled the motivation tanks, and I came home full of piss and vinegar to make major strides in my project. It could have had to do with seeing a beautiful Berkut 13 everyday for a week, or seeing 50 or so canards, or maybe it was a ride in a 200+ knot canard (thanks Klaus!) but I’m raring to go.
Unfortunately, work and social obligations delayed me 2 weeks, but I am off for a bit and the task for the week is finishing. My goal is to get the finishing on the bottom of the airplane through the micro and Cory Bird resin wipe stages, then back right side up before it gets cold and snowy here. It’s August in Minnesota, and that means I’m working on borrowed time, it could snow tomorrow.
So I better get my rear in gear, and this week started with getting the left wing off so that the strake side wing/strake intersections could be trued. These became my references for the seams between the two.
While I had the wings off, I also took the aileron off as it would only get in the way during the finishing process. This proved troublesome. The aileron torque tube had actually corroded into the spherical bearing. When assembling, I had to scotchbrite the cad plated torque tube to get it to fit. Apparently I took enough of the plating off to expose some bare steel that slightly rusted. This was enough to lock the torque tube into the bearing. I had to use a motivator(hammer) to separate the two. So I will have to turn the torque tube down slightly and then re plate.
The wing was then re hung, thanks Steve and Greg, in preparation for finishing. I spent 5+ hours sanding the shiny off all the lower surfaces of the wing, strake, and outboard surface of the winglet to prep for micro application. It went fairly well with the 40 grit sand paper, but in some places I needed to use 80 grit to get into small crevices that were too small for the 40 to fit into. I also used a wire brush in some areas to scratch up some places that I couldn’t get to with paper. That was moderately successful.
Then I used a Berkut 13 Redmon technique for the wing/strake seams. I cut out some .042 aluminum to use as forms for the seams. The aluminum was waxed 5 times, then inserted into the gaps. Straight edges (a level and a piece of angle aluminum) were clamped to the aluminum to keep it true. Then flocro, a mixture of micro and flox was put into e seams to close them up. The flox gives it strength, and the micro gives it a smoother consistency. Later, after the wing is removed, any cantilevered flocro will be backed up by a piece of bid so it doesn’t chip off with wing removal/installation. Incidentally, the same procedure was used for the wing/cowl intersection. Since I did the strake last night, and the wing today, I did get the opportunity to see how well the aluminum releases. Happily, it came out relatively easily, and there was no damage to the seams!
West system micro was applied to the wings and strake. I put it on pretty thick, and my spreading technique certainly needs work, but those three surfaces took a gallon or a bit more of west epoxy. I am sure I have too much on there, but I would prefer to do a bit more sanding at this point than do the micro dance and have to add more micro later. We will see if I am successful on that theory.
Two days of work to prep and apply, and the underside of the airplane is well on its way to getting its white micro coating. tomorrow brings lots of sanding, so goodnight!