RH Wing Fabric Clips

This evening I started putting on reinforcing tapes and installing the clips which hold the fabric to the ribs. It was going well until the sun went down. I guess I'll have to add lights to the tent now that summer and the mosquitos are gone. I did find the same problem with this wing, as on the left wing, with the clips which were added in the field. The hole spacing is too wide to properly install the clips. A little work measuring of the hole spacing and filing solves the problem but it does take time. I don't want to over do it so I file a little and recheck the measurement. As soon as they're in the spec they fit fine.

RH Wing Shrinking & Poly Brush

On the LH wing the outboard seam did not come out straight. It was bowed in towards the root 3/4" in the middle on the top and bottom. I had followed the directions for shrinking an envelope which said to start at the seams and slowly work away from them to keep them straight. It made sense but only worked on the inboard seam. This time I looked to see if I could figure out why and prevent it. I realized the extra fabric around the nav light was probably the cause. The envelope fit tight at the last rib where the metal tip starts. From there outboard it was very loose. I started at the seams with a quick 250 degree shrink on them and the rib bays each side of the seam just to take out a little slack but not enough to pull the fabric tight. I then went to the tip and worked like a fan shape from the nav light inboard on the top and bottom. I worked this just enough to get rid of the slack and pull the fabric so it touched the edge of the tip with no big wrinkles.

Then I went back to the seams and did a slow shrink all the way along each seam. This was to pull them tight cordwise to help resist spanwise movement. From there I followed the original procedure of shrinking out from the seam doing one bay on each side then flipping to do the other side. Do another set and repeat

With the wing tight the seam is as straight as it was sewn, much better.

The wing is now ready to cut just enough to get the strut fittings to slide through. It looks strange to leave tents around such things while shrinking but it's much easier to get the cuts in the right spot.

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The cut fabric was glued to the spar and fitting plate. The gas tank filler and sump holes were also cut and the fabric glued down. Once the glue dries its easy to shrink around the spots to remove the slack.

The fabric was the shrunk at 350 degrees and the first coat of polybrush applied. It always looks strange at this point, with visible drips on the inside, but comes out very smooth.

We're ready for reinforcing tapes and rib clips but we've lost the sun light and I'm tired.

Fabric On RH Wing

The rain finally ended. The slip cover is on the wing ready for gluing. We pulled the cover snug with some spring clamps holding the fabric at the root end. This allowed us to get it close enough to final position to cut the hole at the light for the tip stand. The root was glued first with that end setting on a table. It was easier than working around the stand. Once the root was done it went back on the stand for easy flipping. . . . . . . . . . The aileron cutout and rear strut access were next and the trailing edge of the tip last. It's now ready for shrinking. It looks loose but the fit is just about perfect except right at the tip where it could have been sewn to a better shape. There is about 1" of extra material around the nav light.

RH Wing Ready For Fabric

The Blocks for attaching fabric to around the Tank Filler Neck were made of of a soft wood 1/2" thick with a cross grained ply of 1/16" veneer of mahogany on the top and bottom, making a thick 3 ply plywood. The veneer was badly broken so I replaced it with 1/8" plywood. There is plenty of room for up to 3/4" thickness. Double click on the pictures and you can see the dimensions for the hole, etc. I epoxy varnished the blocks which should now last for the life of the plane. You could probably make them from 3/4" plywood if there is room to widen the thin section a little. On the left wing the filler is that close to the root rib. I could not get the right tank that close.

They're stuck in place with black tar like roof sealant. Once everything is painted I'll seal the gap better with RTV to keep water and gas out of the wing.

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The tank had some spots where fuel had stained it and while there was no evidence of a crack or wear I pressure tested the tank to make sure. A coupler for my 2" hose on the shop vacuum fit snugly over the filler neck. My shop vacuum has a blower connection as well as vacuum. The blower side puts out a nice 2 psi. Isn't it great how life just works out some times. I taped over the gauge opening, it leaked a little, and plugged the drain.

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I connected a low pressure gauge to the fuel line to monitor pressure and used soap solution to look for bubbles on the stained areas. As expected there were no leaks. The stains are in areas which seamed to be the natural flow paths from spillage around the filler neck, still worth checking.

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The wing is now in the tent ready to install the fabric. All ADs and service letters are complied with, the tinnerman nuts are all on, wire is run to the nav light, and the tank is snugly mounted on it's padded ribs. The wing rib lacing is done and all areas needing chafing protection are taped. After a very busy summer working and traveling to fly-ins during dry weather it is now raining here. Once it dries out again we'll get the fabric on and work to get both wings through color before winter.

Tapes Done on Left Wing

We've taken the grandkids camping, been to Oshkosh and waited for the humidity to drop. It finally did on Saturday but not until an intense storm on Thursday which took out the top 80 feet of a tree leaving about 30 feet standing. The poor car took the beating but the wing in the tent behind the broken end of the tree hardly fluttered. Go figure. . Before the spanwise tapes went on, a coat of polybrush over the other tapes was needed. It helps adhesion to have the tapes filled so they don't suck the polybrush out at the overlaps. Also any bumps and rough edges of he tapes were again ironed smooth. The edges of the tapes are brushed perpendicular to the tape to feather the polybrush. It should help create a better finish.

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The tip bow was taped by continuing the leading edge tape all the way around. It take a little longer to shrink it to a good fit without any cuts but I'm doing this for fun not speed.

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I used metal drain grommets. I checked the parts manual to see how many were needed in case they put them on both sides of the ribs or in front of the front spar. They used 12, one on each high side of the rib at the trailing edge. They also used 2 Seaplane grommets to vent the fuel tank bay. I'll have to order those while I cover the other wing. The holes are there in the sheet metal on the bottom of the tank bay.

All the poly brush is done and tapes ironed smooth. It's time to cover the right wing.

Tapes & Patches on Left Wing

I like working with Poly Fiber. The patches on various wear points and around the tank opening and landing light were next. All are cut with pinked edges. I like using a Fiskars Rotary Cutter and cutting board. For straight cuts a plastic straight edge works well. All are available at local fabric shops. Also the scraps of fabric I used for patches were very wrinkled. They ironed very nice at 225 deg. I used my heat press I use for printing tee shirts. It has good temperature control and you just put the peices in and clamp it shut for 5 second. Next I cut all the chordwise tapes to length 107" for the long ribs (at flaps) and 96" for the short ribs (at ailerons). There are a few other shorter pieces needed which I cut as I went. While doing the first side of the wing it's helpful to roll the tape half way and clip them with a large paperclip. It keeps the ends off the dirty floor. . . . The tapes went down as easy as cotton tapes with the Poly Brush thinned 3:1. The big difference is you need to work the Poly Brush up through the tape to wet it. It's what you should do with cotton but it wicks so well it just gets wet even if you don't get a good layer under it. What is really cool is smoothing the edges of the tapes and patches. With cotton and ceconite you spend a lot of time carefully sanding the pinked edges to get them smooth. With Poly Fiber you just use a small hobby iron at 225 deg. I like the Coverite 21st Century that Dondie sold me. The shape of the platen (sole) is much better. It was a little boring but so easy by comparison to sanding and redoping. They really come out smooth, it was great.

Back To Fabric Work on Left Wing

We finally moved the wing to the tent. It really works well. There's room for a table and room to walk around the wing even with it in the flat position. I've secured the cover a little better since this picture. I put eye bolts at each pole and the tarp and cover are tied down to them. It pulls it all tight and the timbers weigh enough to hold it in the wind. It needs a fan in the peak on sunny days. . The first task was to put 4 coats of Poly Brush on the reinforcing tapes to seal them so they don't suck all the Poly Brush out of the Finishing Tapes. I didn't believe it would take four coats but it does. Next the Doilies were glues over the Inspection Rings. Now we're ready for Patches and Tapes.

Tent For Wing Work

The weather and lack of pollen finally allow me to get back to fabric work. Actually I've been to busy in the embroidery shop to get anything done. My friend Caleb Glick offered the use of a tent so I could have an outdoor place to finish the fabric work without carrying the wings up and down the stairs to the attic. We had some planks from the road bed of an old bridge, for a yard project when the weather turn cool again. We used these planks to make a deck where I will one day have a shop/garage. We drilled holes and pounded in some rebar to hold them in place and provide locators for the posts. To get some more head room I made 1 ft. extensions for the posts from 1" EMT conduit. As soon as I get some time in the shop we'll put the cover on and move a wing into it. We also have a large tarp we'll cover it with for some extra protection and to tie it down. Now I won't have to carry the wings in and out every day.

Flaps Are Complete

The fittings and hinges are all riveted back on. Waiting for the AN442 rivets for the end of the control fitting was worth the time. They're in the worst spot to get to and were the easiest to install. With the flat head the tool doesn't have to be perfectly centered. By using one of my dies with a flat ground on one side it was easy t0 get into the tight space and squeeze them. Now I just need to finish writing up the 337.

Flap Fittings Primed

I decided to remove all the fittings from the flaps to check for corrosion between them and the spars. The parts were all plated, poorly, or zinc chromated. There was rust on the back of all of them, stop strikers and actuator fittings. I have them all cleaned up, treated for corrosion and epoxy primed. I also did the engine mount. The aluminum spar was covered in rust from the fittings but had no corrosion. I glass bead blasted the areas to clean them, conversion coated them and epoxy primed. Once the primer is well cured I'll rivet them all back on and finish the paperwork.

Wings & Things

The weather was great and I got all the areas on the wing that were scrubbed for light corrosion epoxy primed. It will need to get a little warmer to get on with fabric covering. Some rivets I've been waiting for arrived today so I can remove the torque tube fittings on the ends of the flaps to clean and prime them. I didn't want to take them off until I had rivets to put them back on. I just want to make sure there is no corrosion behind them, clean them and epoxy prime. I couldn't finish riveting the hinges back on until this was done since the inboard hinge gets riveted with the fitting. Lots of little projects.

RH Wing Ready To Prime

The weather cooperated today, 60 and sunny, so we took the wing outside and cleaned it and conversion coated it. If it's still nice tomorrow I'll get the epoxy primer on all the old metal to protect it where I removed light corrosion. If the weather keeps improving we'll soon be able to get back to fabric work

Flap Hinge Fabrication

The best of the original flap hinges was used as a pattern to locate holes for the new hinge segments. The #10 bolt holes are 9/32" from the outside edge of the hinge and centered on the hinge 1-5/8" on centers. The 1/8" rivet holes are 3/16" from the outside edge of the hinge, one hole is centered and the outer holes are 3-3/8" on centers with the inner holes 3/8" inward. All of that could be measured and done carefully by hand for one hinge. For 6 hinges, per flap, it is quicker to use a Whitney punch and duplicate the holes. The peened end of the hinge was opened and the pin removed. A segment of the new hing material was used to make a master by clamping the old segment to the bottom of the master with the loops pulled snug and centered to locate the holes. The Whitney punch with a nibless punch was used to duplicate the holes in the master.

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The new blank was then placed under the master snugged, centered and clamped so the holes could be transferred from the master to the new segment. This require another modification to the poor old Whitney punch to add a clearance for the loops. This was easily done with a file and some careful cleaning before putting the punch and die back in.

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As each hole is punched a cleco is installed to help assure nothing moves to mess up the hole alignment. The same process was then used to make the other halves.

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The last thing to make was the hinge pins. These were cut from the pin stock with snips, the ends squared up on the belt sander and, a slight chamfer added to deburr the end.

With the pins installed the ends were peened with a hammer making sure both ends were closed enough to keep the pins retained like the factory hinge.

Engine Stand

The snow cooperated to get the engine to the attic. A friend had offered his engine stand but that was just one more thing to carry up to a crowded space. Besides I like inventing things. I have this auto engine stand which I use for the Fly Baby's engine (also a C-85) when it's not on the plane so the plan was to modify it. I had a piece of 3" x 6" x1/4" angle I had used as a second hand bucking some rivets on one of the Cub wings so it seemed perfect for the task. I cut a 2-3/4" hole for the prop hub and drilled 13/32" holes for the prop bolts. On the short side I drilled 2 holes 1/2" dia., 8" apart to mount to the stand. . Leveling it side to side was easy but the stand tips up at a slight angle. I wanted the engine vertical so it would not want to turn and damage anything. I made some wedges from 1/8" aluminum angle, put a taper on one side and left a bit of the flange to get the angle flat. They have a hole in them for the bolt so they can't pop out. I've had those kind of exciting things happen. I also added some washers to move the C.G. forward and strapped a sand bag to the front leg. . . With the come-along hooked to the rafters and a shackle on the lifting lug it was pretty easy to lift the engine into the hole in the stand. I did get the boss lady to help so nothing slipped . The engine is bolted to the angle and we're read to pull the engine back apart. All the machining should be done and it should be just a matter of making sure no rust has developed and oiling all surfaces. I'll also measure everything since I'll be signing for the work.