Delayed time getting into the shop this week. Couple of busy and long days at work left me no energy for plane building (shocker really), and then my first CoVid vaccine (Moderna) kicked my ass for a day and half. Back in the shop on Sunday, but limited energy so things moved kinda slow.
Started the day pulling off the upper skin and deburring all the ribs, triling edge skins and upper wing skins:
Let the nose skin back up a bit to deburr it as well:
Clecoed the skin back down and pulled the A4 rivets for the wing stiffeners. Taking the skin off for inspection later won't be an issue having these complete so got them done:
Primed the edge of the upper wing skin where the tank skin will join over top:
Primed the root support L - did it in grey primer as it will show through the join in the tank and root skins:
Rolled out the nose skin again and applied a bit more green primer that got scuffed up a bit when I was cutting and deburring the slat support slots:
I wanted to strengthen the wing tip plastic so that when it gets riveted to the wing the rivets tails won't pull through or worse crack the plastic. Several builders reinforce this area using 016 strips around the perimeter and I did the same. First though I wanted to back the area where the wing tip nav-lights mount for much the same reasons. I don't know at this point if the nav-light will be riveted or screwed through the plastic, so I made a doubler plate out of 025. Had to rough it out then use the bench sander to trim it down until it fit inside the form to lay completely flat:
Once I had the first one, I made a second one the same for the left wing:
Next up, I went about cutting some scrap 016 into strips to match the inside edge widths of the wing tips. This took some time and I had to break the perimeter into several manageable sections due to the complex curves of the nose section:
This is the hardest section. The inside edge not only narrows dramatically, but curves sharply inwards at the same time. I used a cardstock template clipped on to the edge area, tracing the outer inside edge first:
Carefully flipping it over, I then traced the outside edge (which is the inner edge inside the tip):
This very rough size cardstock template is what I ended up with:
Trimmed out with scissors, I continued to trim it down until I was satisfied with the fit when pinned to the inside curve of the wingtip:
Traced out on 016 scrap and the tail end was left purposely long as I can adjust the length of the next piece easier than fussing with this one:
All the edge pieces, deburred and edge sanded smooth. Inside surfaces scuffed up with 150 grit sandpaper and cleaned with lacquer thinner. More scuff than required for primer, something for the EkoBond adhesive to grab onto:
Being new at using this stuff, I decided to do the nav-light backing plate first. EkoBond on both surfaces after scuffing up both with 150 grit sandpaper:
You have to be careful as the grip is very strong once it starts to get tacky - not much room to re-position once in place, but I got it where I wanted first try:
In hindsight, I probably overdid it with the clamps, but happy with how it turned out:
Overnight curing and that plate isn't coming out!
Same process for each of the strips. I was smart enough to number them to match them up when the time came to place them. If you look close, you can see streaks of blue in the green on the lower left where the EkoBond is still setting up (turning green like the rest):
Started with the complex curves near the nose first then trimmed the long straight pieces at the trailing edge end where needed. Several binder clip, spring clamps and clothes pins keep everything clamped together while it cures:
Perimeter backing strips complete. When I return to the shop on Wednesday night this will be cured and ready for final fit up on the outboard end of the wing. Pulled rivets now have something to grab on:
Between steps (waiting for blue to go green), I got the inboard lower trailing edge trimmed using the Dremel and a cutoff wheel. It's becoming my favourite tool it seems!
Good progress despite feeling like a bag of dirt the last couple of days.
My new pressure sensors arrived in my work mailbox today, so I'll have them shortly for testing. I have high confidence in my theory of how they will work in the fuel system and how to read them using Arduino micro-controller and display.
Onwards... thanks for reading.
p.s. - I'd be wrong not to mention the passing of Chris Heintz, designer of Zenith Aircraft who passed away a couple of days ago, peacefully with his wife at his side. His legacy in aviation stretches from work on the Concorde (yes THAT Concorde) to starting a small aircraft plans business that has grown over 40 years to become the Zenith Aircraft Company, the makers of the aircraft design I am building. His contributions to this hobby and general aviation as a sport can not be overstated. Such a kind and humble soul.
Blue skies and tailwinds Chris - and thank you for making dreams possible for people like me :)
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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.