Wingtip and Filler Work

After ordering and receiving some needed items (Nutplates and Rivets) from Aircraft Spruce, the final nutplates for mounting the fiberglass wingtips were installed.  We also did some more filler work and sanding.  Hours: 1.5

Filler Work

Added and sanded a 2nd application of filler to smooth out transitions, this time to the top side of the right wing at the trailing edge.  Hours: 1.0

Filler added at trailing edge fabric plate

More filler near one of the hinges

Filler added at false rib in back of gas tank

Filler and wingtip, cont.

Continued work on the wingtip and adding filler to smooth out transitions on the right wing.  Drilled holes in wingtip and installed some of the nutplates.  We didn't have enough rivets of the right length, so need to order some more.  3M lightweight filler was added to close in the slots for the hinges (clear tape was placed on the trailing edge surface to cover the slots prior to adding the filler which made the job a little cleaner).  Hours: 2.5

Filler and Wingtips

Filler and wingtip work continued today.  Filler work around the fabric plates and rib-trailing edge interface was finished up.  The 1/4" gap between the Aileron and fiberglass wingtip was cut and sanded smooth and flat.  Aligned with the aileron in its neutral position, the wingtip was clamped in place and the bottom holes drilled and cleco'd.  Hours: 2.5

Filler work around Aileron Pulley Fabric Plate

Right Wingtip Cleco'd on Bottom

More Tip and Filler Work

Got the right fiberglass wing-tip trimming "close enough".  Now the Aileron has to be re-installed for the finally fitting and trimming.  The wing-tip should be aligned with the Aileron in its neutral position.  We also continued working on adding filler along the trailing edge of the wing on the bottom surface.  Areas where filler will be applied were again sanded and cleaned. Hours: 1.0

Wing Tip and filler

Today we began rough fitting of the right fiberglass wing-tip.  Much more work still to go on this as it will take quite a bit of cutting, filing, and sanding to get the wing tip to fit nicely.  We also started prepping the trailing edge surfaces for filler to smooth any rough transitions.  Areas where filler will be applied were sanded and cleaned.  Hours: 1.0

Fabric plates installed on right wing

A few parts that we were waiting for (small nut plates) finally arrived, so we installed the rest of the fabric backing plates on the right wing.  We bent the fabric bracket for the front lift-strut bracket slightly so that it matched the profile of the ribs.  We noticed a little bit of interference with one leg of the bracket, so we filed the slot in the fabric plate slightly to eliminate the interference.

As usual, mating areas were abraded, cleaned, and then two part Hysol epoxy was applied.  Then the fabric backing plates were riveted firmly in place. Hours: 2.0

Fabric backing plate at aileron pulley location

Fabric plate at lift-strut bracket near the leading edge

Fabric plate at flap pulley location

Fabric plate for second lift-strut bracket location

Wing Fabric Rivet Holes Drilled

The holes for fabric rivets in the top and bottom wing rib caps were drilled with a 1/8" (#30 actually) drill.  The locations were duplicated from previous wing and are detailed  in the March 26, 2017 and April 2, 2017 Blog entries.  We also drilled 1/4" drain holes in the bottom inboard trailing edge of the wing.  Nine drain holes were drilled, each was located 1/2 inch from edge of rib cap, and 1/2 inch from front side of trailing-edge.  Hours: 3

Drain hole

Right Wing Gussets and Fabric Plates

This weekend we made some good progress on fabric backing plates and gussets for the right wing.  There is a fabric plate at each point where a cable exits the wing to control the flap or aileron, and additional plates are located at the lift-strut attach brackets.  The fabric backing plates were trimmed carefully around the cable exit points and deburred, then they were clamped in place temporarily while we drilled holes for the rivets.  We used a hole-locating tool (which we had previously made when working on the left wing) to match the hole in the fabric plate to the holes that were already drilled in the lift-strut brackets.  Additional holes were drilled for nut plates that will be used to fasten cover plates on the bottom side of the wing.  All holes were deburred and the ones that require flush-mount rivets were dimpled.  Unfortunately, we didn't have enough nut plates so couldn't finish up the two fabric plates that needed them.  We ordered some more from Aircraft Spruce and will finish those up when they arrive.  We will epoxy all fabric plates on the top-side of the wing once those are completed.

Three fabric backing plates

Fabric plate for lift-strut at leading edge

While we had the wing oriented upside right, we  installed the fabric plate for the upper aileron hinge point. Since no nut-plates are needed for that fabric plate, we went ahead and attached those permanently (Using Hysol epoxy and small alum. rivets). 

Fabric plate for Aileron

We installed small wood gussets for the right wing.  We turned the wing onto the leading edge and clamped it vertically so that the gussets would not move while the epoxy was curing.  Surfaces were cleaned, then these gussets simply epoxied in place.  After the epoxy had cured 30 minutes, the fillets were smoothed with a wet finger.  Hours: 5.0

Wing tipped up vertically and clamped in place

Two gussets epoxied in place

Aileron/Flap Pulley Install

With a little luck and a lot of fidgeting, we were able to get the three pulley brackets aligned and installed. Like on the left aileron, we joggled the top control horn for better alignment.  We used the same procedure as before and it worked wonderfully.

After the brackets were aligned correctly, the rivet holes were drilled, deburred and the brackets were riveted and epoxied in place. Hours: 4

Joggle in Aileron Control horn for Alignment

Aligning the top Aileron Pulley

Flap Pulley Bracket installation Complete

Top and Bottom Aileron Pulley Brackets Installed

Aileron, right wing

The aileron needed 30 deg down deflection from neutral position, but we were only getting 25 degrees.  We trimmed a little bit of fiberglass at the front edge of slots in the aileron leading edge that were hitting the hinge, and that helped get us to 29 degrees deflection.  At this point, we ran into another issue as the fiberglass no longer interfered, but one half of a new aileron hinge bracket that we made was now interfering.  We noticed that when we made this aluminum hinge bracket, it was slightly wider than the one we replaced, so we filed down the edge slightly which gave us more clearance.  Once we corrected this, we were able to get close to 32 degrees deflection down, which is sufficient. 

We also began planning for installation of the aileron pulleys on the right wing.  We clamped the lower pulley in place temporarily, and need to check alignment carefully before drilling any holes.  We ran into alignment issues on the left wing that required us to make a new bracket, and may run into similar issues with the right wing.   Hours 2.0

Fuel Tank Gap Rib Final Install

After cleaning and sanding the mating surfaces, the Fuel Tank Gap Rib was epoxied and riveted in  place using the Hysol structural epoxy.   A section of cap strip between the Gap Rib and the leading spar was carefully cut to size.  After sanding and cleaning the cap strip and fiberglass tank the cap strip was epoxied and held down with weights until the epoxy cured overnight.

Fuel Tank Gap Rib and Cap Strip Epoxied in Place

Next we started gathering the parts for attaching the aileron pulley assemblies.  We checked the aileron deflection with a angle meter, checking for 30 degrees either way.  We noticed we easily get the 30 degree down deflection, but having to tweak the opening on the fiberglass aileron leading edge to allow full 30 degree up deflection.  We're trying not to remove too much material, so it's a tedious on/off process  to slowly creep up on a little more than 30 degrees.  Hours: 3

Measuring Aileron Up/Down Deflection

Fuel tank gap filler rib

A short rib that will be attached between the fuel tank and the trailing edge (providing a surface for fabric attachment) was readied for installation.  It will be installed half way between the ribs that are on each side of the fiberglass gas tank.  The rivet holes for attachment were drilled, and the trailing edge aluminum was dimpled for counter-sunk rivets.     Hours: 0.5

Right wing flap and aileron hinges

Installed the flap and aileron hinge plates for the right wing.  We were more careful this time when drilling through the ribs for the flap hinges by drilling through one hinge plate and the rib before lining up the 2nd hinge plate.  This helped guarantee that no holes were accidentally drilled off center, as we didn't really want to make another hinge if we didn't have to.

The hinge plates and mating surfaces were scuffed and cleaned, and then were epoxied and riveted in place.  Below is a picture of one of the hinges.  Six hinges total were installed (three on both the aileron and flap for the right wing).   Hours 3.5

Aileron hinge riveted and epoxied in place

Right Wing aileron hinge

Drilled holes through the right wing ribs for attachment of the aileron hinges.  Made a mistake on one bracket as the two halves of the hinges did not line up perfectly when drilling, so created oblong holes on one of the hinge plates.  We fixed this by making a new aluminum hinge bracket from 0.063 aluminum.  The manual says to simply swing one bracket plate out of the way before drilling, but that's not as simple as it sounds with everything attached and clamped in place.  Hours 1.5