Right butt rib work

Today we had a warm enough day to open up the garage so we could access the right wing and work on the right butt rib.  We had previously measured, cut, and drilled the T-mount that hold on that butt rib, but we noticed that the root rib on the wing just wasn't quite lining up correctly with the butt rib. We should have had 1/16" gap because we used 1/16" spacers to set the gap, but after setting everything in place with Clecos, we had no gap on top, and a larger gap on the bottom. This seems to have been caused by a combination of things, including a slight defect in the T-mount (not welded perfectly perpendicular), slight bowing to one of the ribs, and minor slop in the T-mount fit.

We made a variety of adjustments to take care of this, including sanding the root rib back slightly (about 1/16"), and welding a tiny bit of metal to the bottom of the T-mount so that it would fit tightly in the hole while angling it up a bit to help with alignment.  Also, similar to the issue we had with the left butt rib, we had to sand back the surface that is adjacent to the spar tube because of slight interference.  Once we made these tweaks, the butt rib lined up nicely with the root rib along the top edge with just a small gap (about 1/16"), and we riveted the rear T-mount.  The front T-bolt needed some paint before installation as some paint was removed to do the welding.  A coat of paint was applied to the bare surfaces of the T-mount, and we also varnished areas of the butt-rib that were previously skipped.    Hours: 2.5

Michael riveting the rear butt rib T-bolt to the fuselage

Left Butt Rib Final Install

After doing a final fitting of the butt rib it was removed and exposed wood was coated with three coats of Spar Varnish to seal the rib.  The exposed metal of the mount tabs were sprayed with one thin coat of paint.  Once everything was dry, the tabs were installed on the fuselage with CCP-42 rivets.  Hysol epoxy was used on the T-mounts along with the four rivets to secure the butt rib to the T-mounts.

Also, we put light-weight filler on the rivets used to install the anchor nutplates on the top Aileron fabric plates.  Hours: 2.5

Left Butt Rib Installed

Butt Rib Front T-Mount

Butt Rib Rear T-Mount

Left Wing Top Aileron Fabric Plate w/Filler

Control Pulleys

Installed some more control pulleys.  We found what appears to be a mistake in the manual where they called for AN4-17A bolts for some of the aileron pulleys, but those are too long and the nuts bottom out before tightening to the pulleys, so we swapped them out for 4N-15A.  Didn't have enough of the shorter bolts so we have to order more. 

Ran into another issue when we went to install plastic fairleads that protect the cables.   We have 20 fairleads, but are missing the clips to install them.  They are checked off on our inventory, which means they are "somewhere" in the shop, but can't find them anywhere after searching for 45 minutes.  So looks like we'll be ordering some of those, too.
Hours: 1.0

Butt Rib, Control pulleys, etc

We made some tweaks around the left butt rib because it didn't line up cleanly with the root web, causing slight interference whenever we would open or close the wing.  To fix this, we sanded back the front edge of the butt rib slightly (area adjacent to the front spar), and also sanded a sliver of material on both the butt ribcap and root ribcap so that that we had an even spacing between the two.  After making the mods, the issue with interference was fixed.

Top of butt rib (right) and root rib(left) shown

We also added four nutplates to one of the fabric plates on the right wing which will allow us to (later) easily add a fairing at the exit point where the cable runs to the rudder. 

four nutplates installed with flush rivets

Lastly, we installed eight control pulleys inside the fuselage.  These pulleys are for the cables that will ultimately run from the controls to the rudder and ailerons.   We either used up all the washers we had for AN4 bolts, or misplaced them, so will have to order a bunch more.   Hours 2.0

Double pulleys installed, one for ailerons and one for flaps

Left Wing Butt Rib

Did the final placement of the left wing butt rib.  Had to do some tweaking to get the spacing corrected to the 1/16" called out in the builder's manual. Once aligned, two 1/8" holes were drilled, one in each location to fix the root rib in place.  Cleco's were placed in the holes for riveting at a later time.  Hours: 1

Butt Rib in Place

Left Wing Top Aileron Fabric Plate

Decided to add four nut/anchor plates to the Top Aileron Fabric Plate.  The plan is to add 3D Printed cable fairings to the reduce cable drag.  Got to use a new tool, the Anchor Nut Drill Jig I got off Ebay.  It worked wonderfully and made for a nice quick installation.  After drilling the holes, the anchor nuts were riveted in place using a solid rivet squeezer.  Hours: 0.5

Anchor Nuts added on Top Aileron Fabric Plate

Right Root Rib Work

With the weather being rather nice, we decided to take advantage of it and unfold the right wing out the garage door.  With the wing unfolded we were able to work on the right wing root rib.  Like the previous day on the left root rib, we positioned the root rib on the wing with 1/16" spacers.  We found an excess of epoxy on wing would not allow a clean fit, so we had to do a little cleanup with a Dremel and file.  Once that was taken care of, we marked and cut the T-Lugs to size.  The holes were then drilled and cleco'd .  Hours: 2

Ed filing excess epoxy

Left Root Rib Work

Started work on installing root rib on the left (pilot) side of the fuselage.  The wings have to be swung back a few times and we had to re-arrange things in the garage to accomplish this.  Root rib fixing lugs (T-shaped pins, W-0290)  had to be cut down to a shorter length and the powder coat paint removed for fitting into the mating bushings on the fuselage.  The root rib was aligned with the wing end rib with a 1/16" gap between the two.  We used four pieces of 0.063" Aluminum shims for the spacing.  Once everything was aligned and spaced correctly, four holes were drilled through the top "T" into the butt rib and cleco'd in place.  Hours; 2.5

Overview of Butt Rib Cleco's in palce

Rear T-Pin Cleco'd to Butt Rib

Front T-Pin Cleco'd in Place

Leading Edge Cuff Template

After hearing great reports from Steve Henry of Wild West Aircraft, we decided to purchase a set of wing leading edge cuffs.  We were provided a cardboard template for placement assistance.  To provide a little more durability we transferred the template to double thick plywood and cut to shape.  Hours: 1

Here you can see the Leading Edge Cuff

Leading Edge Cuff Placement Template

Right Wing Fabric Plates

As stated in the previous blog entry, when we originally did the right wing fabric plates, we did not install the anchor nut plates.  Tonight we installed six nut plates with solid rivets and two nut plates with pulled rivets.  The pulled rivets were used because we could not get access to the back of the rivets with a rivet hand squeezer.  Hours: 1

Anchor Nut plates Installed on 1 of 2 Fabric Backing Plate

Right Wing drains, etc

We drilled 1/4 inch drain holes in each bay of the right wing, similar to what we had already done on the left wing.  We also drilled holes in two of the fabric backing plates on the left wing for installation of nut plates.  Again, this is something we had done on the left wing, and needed to duplicate on the right wing.  The rivet holes were either dimpled or countersunk (depending on the location) because we'll be using flush-mounted rivets.  Hours: 1.5