slats, slots, slits

This build is like a Dr. Seuss rhyme sometimes, repetitive and fun but smoothly flowing along.

Been a over a week since my last blog post.  I got to the shop for a couple of evening visits and weekend day, so progress continues.  Home internet has been flaky until tonight, so I've been saving pictures and updates for this post.

Now that the nose skin is fit, I needed to figure out a way to line up the slits in the nose skin where the slat pick-ups protrude through from the nose ribs.  The lower half of the nose skin is already rivetted to the spar so I have to cut those slots with the skin still attached.

 I started by laying the skins flat at the edge of the workbench:

Here is a slat pick-up at the outboard end of the wing, clecoed into it's spot on the rib.  I chose this one to do first to prove out the plan for making the slots - there is only one pick-up through the outer nose skin, making manipulation of the skin easier.

Carefully measuring the slat pick-up in it's final position tells me the bottom edge at the rib is 70mm infront of the front most lower rib rivet.  The top edge of the slat pick-up is 160mm from the front most lower rib rivet - that means the total length of the slot around the curve of the nose rib is 90mm, starting at the 70mm mark:

With the knowledge the nose rib is perfectly square to the spar (I double checked), I took out the top cleco and simply tilted the pick-up forward and down to establish the location of the slot referenced to the rib:

A ruler confirms the extended line paralell from the rib matches the slat pick-up

Here are the measurements sketched out on the inside of the nose skin along that extended reference line.  This will be the location of the slot:

I doubled the line to the width of the slat pick-up.  This thin rectangle will be the bounds of the slot:

An A4 hole gets drilled at each end, then the slot is cut out with a Dremel tool:

​To prove the measurement is correct, re-attached the slat pick-up to the nose rib, then I re-wrapped the outboard nose skin back and secured it to the spar and nose rib.  The slot fit is tight, but if careful I can slip the nose skin over the pick-up - it lines up very nicely!

All the rivet holes in the nose skin still need to be deburred as does the slot, but very happy my head scratching over this paid off:

With the knowledge my method works, I final rivetted the nose skin support Ls in place on all 3 slat supports at their nose ribs:

All the fitting of the slat supports done previously were done to a template when off the wing, and the slot holes should be in the same places, but I measured each to be sure and they were indeed the same.  So I repeated the process for the two inner ones:

Slots for the outer 3 cut and fit up real nice once the skin was wrapped over and secured again:

The inboard slat pick-up by the wing root does need a slot - the nose skin wraps to one side.  The root nose skin is attached on the other side of it:

Final sized the trailing edge to the rear channels, and add the joining rivets where the trailing edges overlap:

Took the wingtip out and trimmed the upper skin and trailing edge.  This still needs some more trimming once the wing tip it final fit - lots more to come on that front.

This is the open fuel tank bay.  I took the bay cover off to assess fuel tank fit in preparation for building them, lots to plan for here.

Sitting down with a cold drink of water, I couldn't help admire the symmetry of a wing being built and wonder hole many holes/clecoes and rivets I've done so far!

Right sized the nose skin rivet holes up to A4:

Started adding the requisite 4 rivets into the support L behind the nose skin at the slat pick-ups.  These will eventually be A4 size, but I need to find the long drill bits for the middle two!

Took this picture of the wing structure looking in from the wingtip.  Just noticed a smiling man-in-the-moon face looking back at me way from the other end!

Nose skin, nice and tight to the nose ribs and rivets holes properly spaced:

Took the trailing edge clecos out, deburred them and the rear channels.  Then laid out some newspaper for priming the edge that will tuck under the upper wing skin:

As I been pondering fuel tanks, I been thinking on how to plumb them to incorporate the pressure sensors now on their way from where I ordered them.  I recieved some other plumbing parts this week.  From right to left - tank flange, finger strainer, 3/8NPT-AN6 swivel adapter, AN6 "T" with 1/4NPT takeoff and (for now) brass 1/4NPT union to join to the sensor when it arrives.  I'll likely swap out the unions for blue anodized aluminum to match the rest:

All the fittings loosely together - all joints will be tighter and sealed with fuel safe joint sealer once installed:

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The other part of my order arrived too.  I plan on brazing the tank sides and skins together and the fittings using aluminum brazing rod.  I ordered this highly recommended brand:

These rods essentially work like solder, but at a much higher strength and temperature.  The rods melt at a temperature much below the melting point of aluminum, so you heat the pieces you want to join and flow this into the joint, then let it cure (solidify).  I've haven't done this before, so I'm certainly looking forward to trying it, learning and making my own fuel tanks!  Trying to figure out how to capture that process on video to share it.

Progress, but so many little details.  It's hard not to feel bogged down, but this blog helps remind me how far I've come on the build and my learning.

Thanks for following along, stay tuned for more!