Ok, funny story.
I went to the local hardware store to pick up some items. I needed some stainless machine screws for the trim cover plate and Brenda asked me to pick up some paper towels for thous house. I also picked up some 6mm drywall vapour barrier plastic, and a large roll of duct tape. While standing in line, I noticed some work gloves on sale, so I add that to my cart.
While checking out my stuff, I realized I had most of the makings of a murder kit! I mentioned that to the cashier whom I happen to know and we had a good laugh. No, I'm not planning anything nefarious!
With the machine screws in hand, I was able to secure the cover plate. Worked well, but I had to enlarge the holes a bit to make up for some slight offset in the rivnuts.
With everything done on the stab and elevator that can be done before fitting it on the fuselage, it's time to wrap them up for storage in the barn.
Nice to see an open bench again! I decided to start on the flapperons next, as I already have the ribs bent/formed. Can't believe it was over a year and a half ago I did them! (see this post).
The plans are quite detailed here, even though there are fewer parts. The flapperons are built in four sections, an inboard and outboard section for each wing. As such, there are left and right ribs with varying orientations, Like the stab and elevator, I found it easier to lay all the parts out for inventory before beginning.
In studying the plans, I came across a small discrepancy. The flapperon control horn (part 75A1-6) shows 2 different shapes. The overview assembly page shows it like this:
The part dimensional drawing matches as well:
But the assembly/rivet drawing shows a different shape (circled in yellow below).
I emailed Roger Dubert at Zenith who got back to me right away. Thankfully the dimensional drawing is correct and thankfully I won't have to remake mine. He was kind enough to include an updated rivet/assembly detail drawing as well. Not sure I saw this anywhere in the update pages. Problem (if it even was one) solved.
It's important to accurately place the ribs on the spar, as the flap bracket spacing must match what is on the wing when it is built. I decided to do the inboard flaperrons first, as they are slightly more complex. To start, I lined the left and right spars back to back and matched measurements for the rib attach points. These finger clamps are perfect for this task and this will make them the exact same.
Drilled the spar holes out to A3 to start, then back drilled through the spar into the rib flanges.
Here, the plans could use some clarity. No where do the plans tell you how far the outboard rib of the inboard flap stands-off from the spar. The dimension I needed is shown in yellow below.
The only way I can figure is to complete the root end then measure back to the outboard end. This will work as the root rib has specific placement and is "toe-in" a bit to match where the fuselage narrows behind the rear cabin post. At this point, I also used a sqaure HSS tube to act as my straight edge to make sure the nose ribs and line up parallel to the spar. This made measuring the "toe-in" easy too.
With the root rib in place and secured to the bench, I can measure back to the outboard rib and adjust as necessary. The measurement is defined by the width of the flapperon skin with the widest dimension measured from the tail of the root rib to the tail of the outboard rib. I marked this on the plans as I will need it again for the left side inboard flap.
The left inboard flap went much quicker, just had to remember the ribs face a different direction. I lined them up facing each other against the steel tube and everything is square and identical.
With the inboards done, the outboards went smoothly too. The rib placements are similiar, but the process is the same. This time the inboard rib is square to the spar (no toe-in) and there is no outboard tip rib. The tip is a fiberglass aerodynamic plug that is inserted later (I'm considering 3D printing it!).
Next were the flap attach brackets, made from 6061-T6 angle. 65mm long.....
....cut and beveled and corners rounded off. Still some fine sanding to do to clean them up before paint.
Marked for drilling.....
.... and drilled to A4. Until these are in position, I'll leave them at A4, but final rivets will be A5.
Here is the first one in place. The bracket needs to extend 26mm through the flap skin. This piece of wood I'm using is about 28mm tall, so this is correct accounting for the 0.016 skin. I'm happy with the fit.
Really happy with my time spent in the shop over the last couple of days. The flapperons are well underway and I'm looking forward already to the dreaded slats!
I was thinking I wasn't going to post the following video because I'd like to think fellow builders are a smart, rational and analytic group. But the more I see on the news about the ignorance of people regarding Covid-19 and the steps EVERYONE needs to adhere to it wouldn't surprise me that some still need the reminder. Take it for what it's worth. Be careful, be smart, be safe everyone.... FLATTEN THE CURVE!!
Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.