Saturday, July 25, 2015

Easy Repair #17

Ready for rigging now I've moved the right wing panels onto the frame I had bolted to the floor when I completed the pre-rigging from sheet #3.

As I put the struts in place, I recalled the problems I had noticed when learning to fly. I took great pains to patch all the tears and holes in the glider I inherited only to have the leading edge root strut bracket punch a hole right through the nice patch I had put over the previous hole. Here is a photo of that bracket “after” I drilled out the rivets, flipped it and re-installed the rivets.

It turns out that there is plenty of clearance now on both sides of this bracket and I get no contact with either the fabric or the gusset with the bracket in this orientation. The strut fit is not changed. If you don't do this, expect to see a nasty hole punched through the fabric by the rivnut end as shown here on Darrel's upper wing panel trailing edge which I had just patched prior to realizing what was causing it.

I found it far easier to do the tail swage first, fit the cable loop over the bracket bushing, snug up the main swage and then compress it. The plan sheet says to do the main swage first which I tried at first and right away switched to doing the tail first. Another thing I'd do different would be to thread on shrink tubing PRIOR to all swaging. When I got to the end and saw where the cable ends contact the fabric I found it necessary to tape over all the swaged cable ends. In the folded storage/transit position there was a fair amount of abrasion happening not to mention getting holes poked in my finger tips from the cable wire sticking out of the secondary swage during set-up & tear down.

I used a random piece of plastic channel I had laying around, cut off what I didn't need and used it as a spacer to set the position of the main swage right where I wanted it. If you look close you can see where I used a hot knife (soldering iron with a blade tip) to melt the clear vinyl coating in order to strip the cable prior to swaging).

In this shot I am setting the final tension on this flying wire using two vise grips held with my left hand while tightening the wire clamp with my right hand. Otherwise I'd have needed to find someone to help. This worked fine.

I made multiple trials to get the tension on all the cables just right and it took a fair amount of time to do a decent job of getting them all “just right”. My swage tool (I finally had to buy one) was a short handled Nicopress model 32 VC-VG which does both 3/32 and 1/16 swages. It required quite a bit of muscle for the 3/32 swages so I ended up cutting a pair of extension “handles” from 1 ½ inch PVC pipe. The other critical tool I was lucky enough to borrow from one of the EAA members was a Felco cable shears. This made all the cable cuts a piece of cake producing nice, clean ends.

No photos of my trials locating the control cable inside the tip of the lower wing panel. Located a hole based on how Darrel's cable was deforming the fabric and hot knifed it free-hand. Turned out fairly crappy. Should have taped a nice circle template and cut to that instead. Since this was a re-build, the bushing was already swaged onto the cable end so I had to make the hole big enough to fit the entire thing through the fabric. Rather than do an actual fabric patch (would require me to do a spot re-paint) I just used adhesive-backed sailboat Dacron patch tape which worked OK.
Next I rigged the rudder return spring exactly like I re-configured Darrel's where I removed the bungee approach specified in the UFM plans (a poor solution I felt) and installed a nutsert (that's what the guy at True Value Hardware called it).

I picked out a spring from the hardware store spring selection and attached it to the wing tip using two nylon washers and a small bolt.  I also picked out a steel pin, drilled it to accept a safety pin and used this as a quick connect to attach the rudder control cable during assembly.

The next step was to rig the control cable which involved wrapping it around the twist grips per the plan so that the rudders come back to neutral when released.

I really liked the grip material Darrel had on his glider which was cloth handle bar tape for bicycles. I had a hard time getting anything close to long enough. The best I did was less than 10 ft so that's what I used. The underwrap was just electrical friction tape followed by the cable winding then covered by the bike tape and terminated with vinyl electrical tape on both ends.

Now I am nearly done. I got worried about the paint sticking to itself in the folded storage and transit position so I decided to wax every surface except the bottom of the lower panels using the Poly Fiber recommendation of a non-silicon based Carnuba wax which took me a good part of a day to do but I'm glad I did as you will hear about in a minute. So here's the completed glider ready to pack up and take it's second flight (recall the first one ended in disaster over 30 years ago...hence this project).

Here I am at the local test flight area the next day on the Oregon coast (Cape Kiwanda) in perfect conditions....low tide, dune to myself with a 9mph breeze right up the hill.

Although you cannot tell from this photo, the glider is sitting on a tarp I staked down in the sand so that the glider never touched the sand.  I just could not bring myself to allow that after putting all this effort into the build.
I weighed the finished glider just to have an idea how much over weight I was and it came out at 66 lbs which is about 16 lbs over. I can feel the difference just carrying the individual wing assemblies and knew I was going to have my hands full getting this thing up the dune. I was right, I made it up to about 2/3 of the way to the very top and just decided I'd be so wasted if I went any further that I'd be too exhausted to safely launch it. I was determined to not even allow it to touch the sand that when I got as far as I was going I basically took off in what felt like 10-11mph breeze. Launched fine, flew fine, rudder response was fine and the landing was easy. I could not even visualize making another climb up the dune so I packed it up and went home with a smile on my face. This makes 19 flights in an Easy Riser for me to date. I now need to find an inland site where I can get some altitude with a low risk launch and wide open landing area. I will consider this blog, which was intended to cover my experience in building the glider, completed. I may choose to add notes on things I plan to add or change in the future including how I fit a parachute to the glider, how I rig a comfortable harness and what I do about covering the gap on the upper wing, etc. so watch for those entries if you are interested.  I'm also interested in putting handles on the twist grips as Brian Porter suggested I do.

I hope this helps anyone out there in building an Easy Riser as that was my original intent. If you are interested in my experience learning to fly, please visit my other blog dedicated to the learning aspect of the Easy Riser at

Wednesday, May 13, 2015

Easy Repair #16

Since no one offered use of their paint booth last October, I was forced to wait until spring. So, here we are, April 2015 and already plenty of days warm enough to paint, however.....I ran into trouble last fall. I shot the rudders with Polybrush right over the old dope finish and then Insignia white color base coat and proceeded to mask the accent stripes. After making a masking error requiring tape removal, I found the base coat peeled off with the tape right down to the old dope finish. No point in going further. Ripped off all the covering on both rudders and set about prep'ing the frames for recovering. This pretty much shot the idea of completing the painting last fall. I found that the left rudder had actually sustained some damage once I had the covering removed so I fixed that and beefed up the aluminum ribs which are definitely the weak link in the frame structure. Here's a shot of the rudder frame leading edge rib before.
I cut out a piece of ½ inch foam from the damaged wing rib to fit inside the aluminum rudder rib. I glued it in place using Gorilla glue which is supposed to work well on this type of foam. The stiffening effect on the rib was amazing. If I build another ER, I'd use this on all the aluminum ribs in the rudders which would also allow one to rib stitch rather than rely on the dicey fabric to aluminum bond using fabric cement (without the foam insert, the rib would just collapse as you tightened the stitch knot).

I recalled covering these rudders back when I first built this kit that they were very difficult to do without many wrinkles so both these rudders were ugly anyway. I decided to try a different method this time around and built a quick frame out of 1X2 fir and attached a piece of fabric to it using an office stapler.
I cleaned up the aluminum frame, coated it with Polytak fabric cement and then place the wooden frame over the rudder structure.
A small slit for the rivnut to poke through allowed the fabric to lay down nicely onto the rudder structure. I then ran a very thin line of 50/50 cement/MEK around the entire perimeter of the rudder, rubbed it in and let it dry (std process).
I then simply cut around the perimeter leaving enough fabric to do the wrap onto the aluminum structure and got an almost wrinkle-free main area. The hard part was doing the snips and cuts to get the fabric fitted around the ends, brackets and horn. Repeated the frame process for the other side and ended up with no wrinkles after doing the final shrinking at about 300 F. Wetted out the glue on the ribs to attach fabric then applied Poly-Brush (coat #1 brushed on, coat #2 & #3 sprayed on). Same pin hole bubble issue. Just have to re-brush back over what you've just applied as you go to knock down the bubbles before the P-Brush tacks up. What you don't get will be ironed out at 225F prior to spraying.
Here are the rudders after completing all the gluing, smoothing with the iron and general detailing finishing with the first brush-on coat of Poly-Brush.

Here they are after the final sprayed on coat of Poly-Brush......

OK, on to painting. I've poly-brushed the rudders and shot the base coat of white. Two coats was sufficient. One thing I've found in getting an even coat aside from being very smooth and even on your gun passes (you need to always be aware of how far the nozzle is from the surface, what angle the spray fan is relative to your gun pass direction and how fast you move the gun along the surface). It's a tough job and was hard for me to do. I would finish a panel and then go back and look for uneveness. I would then spot spray the light areas until the whole thing looked relatively even. I tried to put on just enough color on the first coat so that the second coat was the final one. In the photo below, notice the different color masking paper on the leading edge at mid span. That stuff is the paper you use when you paint a room in your house which I suspected when I experienced bleed through. I'm not sure if it's the paper because I went to an auto paint supply shop and got their masking paper and had a little better luck but still saw it bleed through a little. I think the take away here is to DOUBLE LAYER THE MASKING PAPER OR USE A WIDE BORDER OF TAPE next to the paint line. Also helps if your technique is good enough to allow very little paint overlap onto the masking paper.  As you can see in this photo, I don't do a very good job of keeping paint off the masking paper.  I was fixing a screw up here where I forgot to take the accent stripes all the way to the root on the lower panels.  I am leaving a gap at the root on the upper panels where I will strip the paint back and glue on a fabric closure with a zipper after I'm finished.  Darrel did this on his and it works really slick.

In this next photo, I've removed a piece from the other wing panel where I had used it right in the area I was painting. You can see what happened.....bleed through! So go find your local supplier for automotive painting and get your paper from them but I'd still test it first before you commit to use it to mask an entire took me a couple hours to finish one panel and that was after I got the hang of it.

I used Reducer on a Q-tip in an attempt to mellow it out a bit with limited success. I went over the area with red but could not make it go away.

Here are some shots of the masking involved in creating a simple design scheme similar to the lines on the glider Brian Porter flew in the 1976 National meet.

The blue tape in that shot is vinyl tape used in automotive trim masking. You can form it somewhat around curves. I could not do a real tight curve successfully and ended up cutting the curves for the rudders which were much smaller radii compared to the wing panel curves.

Back in the converted RV shed with the drop-down lights for painting.

Masking the rudders.

The finished rudders ready for painting.

This next photo shows my attempt at getting an even first coat of red on the rudders. I always shoot the edges first since this is where the risk of generating drips is greatest. Making a couple light passes worked best followed with filling in the rest of the surface.

Here is a shot of the final accent stripe of gold as I am removing the masking tape around the curve. Gives you an idea of the cutting and fitting I had to do in order to obtain a nice tight curve around the bend.

One thing I did which really helped get the last little bit of paint out of my cans was to use a metal shears and cut through the lip gutter then pour out the last bit of paint and rinse with a little Reducer.

I got a couple small areas where the color pulled off the Poly-Brush surface with the masking tape. Likely some contaminate I neglected to get off prior to painting. I'll need to touch it up with a fine tip

brush later.
Here are more shots of the rudder masking for both the red and gold accent stripes. Lots of time masking and re-masking to do even simple paint schemes like I'm attempting here.

As a side note, it was 58F and raining when I shot these.  I saw no problem with the paint nor did I note any difference in spraying under these cool conditions.

Friday, October 24, 2014

Easy Repair #15

Post #15

Finally got going on the build again but it will be tight this fall getting enough warm weather to paint before winter sets in. Rib stitching was the task I had been procrastinating over all summer and when I started my learning sessions on the inherited Easy, it really killed the re-build project. I used the modified Seine knot. I followed a good YouTube video from Cormanairpark that got me finally going on this task. Here's the link;

I abritrarily chose 3 inches as my spacing partly because I had to keep the fabric tension so low that I was concerned about airfoil deformation during flight. I don't recall what the plans called for but I believe it was more than that. The following shot shows the first panel I did after marking off the 3” lines using a chalk line.

This really made a mess and I marked the rest using a piece of 1 inch wide aluminum strip I got from the motorized parts kit. It was flexible and easy to hold down onto each rib and just mark each position with a pencil. I spent some time figuring out how I could mark out the bottom of each panel so that the stitching cord was close to perpendicular with the top rib cap strip. That way I got a nice, even 3-inch spacing on the top surface and let the bottom spacing vary to maintain the 90 degree angle with the cap strip. Just like the plans show, prop up the wing panel you are going to stitch on a couple of saw horses and go to it. I followed the Poly Fiber (or Stits) covering manual process pretty much to the letter on this. The second step (after marking out the spacing lines) was to apply the ½ inch tape which you see here.

The next thing was to take the needle and poke holes through the fabric on both sides of the rib right on the mark up spacing both top and bottom. Once that was done, I propped up the panel onto the saw horses and started the stitching process. I was able to do all the rib stitching with no help and it wasn't all that difficult, just tedious. The hard part was getting the knot good and tight before going to the next knot. I untied many knots that I wasn't satisfied were tight enough to suit me and this really slowed things down. A couple times I broke the cord halfway through the rib and chose to splice it using a water knot (this can be found in most rock climbing books) rather than start the rib over again. I found it fairly easy to tear the fabric with the cord when I wasn't being careful during the knot tightening part. I had to be very careful of the direction I was pulling during knot tensioning.

Once I finished all the panels I wiped down each stitch using the Poly Fiber R65-75 Reducer solvent. Depending on the batch, the wax can be very thick on the flat stitching cord and it ends up all balled up right on the knot. You won't get it all off and it didn't mess up my paint job as I found out later so don't sweat this too much, just give it a wipe down. The next shot shows me using 3 parts Poly Brush to 1 part R65-75 Reducer to saturate the sticky back cloth tape applied over the rib cap strips. The Poly Fiber manual says it normally takes 4 coats to “fill” the tape with Poly Brush. I thought this was excessive and then found out that 4 coats was just about right.

Now you have to start thinking about how you want your taping to come out. I ran a 1 ½ inch tape over the stitched ribs but stopped short at both ends which made it tough to cover with a leading edge tape or trailing edge tape. You decide here what you want to do. I used an 1 ½ inch wide brush in applying the Poly Brush pre-coat doing half the rib.

Now the tape goes down.

Working fast need it to completely wet out the cover tape.

This shot shows me after I top coated the first half and completely wet through the first half of the tape. I'm now doing the second half pre-coat.

Finishing this rib up by going over the tape and pressing it into the wet Poly Brush.

I didn't hesitate to add a little more Poly Brush as I was doing this. The idea is to get the tape wetted completely through without adding any more Poly Brush than you have to in order to accomplish this.

Next, I turned my RV shed into a paint booth. Here's the results of the first spray coat of Poly Brush.

I borrowed an HVLP turbine from the EAA club nearby but bought my own gun.  I could have borrowed the gun also and actually did for the first panel of Poly Brush.  I then reverted to the gun I'd bought which I felt I had more adjustment with.  I just followed the Poly Fiber manual on this and it was fairly easy except for the leading and trailing edges. It was really touchy keeping these areas from forming drip lines. When this happened, I had a 2 inch brush handy in a jar of R65-75 Reducer and I quickly brushed any drips away. This worked well as long as I was very conservative on the amount of reducer on the brush. I ended up with some contamination streaked areas in spots that would not take the Poly Brush. After freaking out, I decided to wipe those areas clean right down to the cloth and then re-brush and then re-spray. I got the areas to “take” but you could easily see the brush marks left even after the final color coats. I believe this must have been something on the rag I used to wipe down the panels since they had been brush coated nearly a year ago. Once I got the panels all coated with a couple of passes of Poly Brush and was convinced they were sealed, I went on to apply the Poly Tone color coat. I was surprised at how much I had to apply to cover the pink Poly Brush (I used a white color coat). It turned out I really couldn't see what I was doing in this shed so I added 8 four foot dual tube flourescent shop lights and hung them with about 3 feet of clearance over the panels. What a difference! I ended up doing a second session and getting the panels I didn't quite get covered the first time. The keys here were;

a) spend most of the time doing a good job masking (the paint will go EVERYWHERE)
b) use multiple light passes on the leading and trailing edges to avoid runs
  1. you can't have too much light.

I didn't get any photos of the white base coat but one of the issues was getting even coverage. Since the idea here is to put as little paint on as is needed to just cover the panel and no more. This stuff addes weight but you'd be amazed at how hard it is to get enough on to completely cover the pink Poly Brush. I tried both chord-wise passes with the gun and span-wise passes and really had no preference in results although it was much less tiring to go span-wise. I found that aiming the center of the nozzle right at the line of the last pass gave me the right amount of overlap to avoid serious banding. It just takes practice.
Once the base coat was on I started masking the next day for the accent color stripes. Here's where you'd better be real careful about COMPLETELY and I mean COMPLETELY mask off where you don't want to have paint going where you don't intend it to. I've already shot the red accent and this is the gold going down last.

Remove the masking and we have.......

Looks good to me!

I didn't find it necessary to mask the bottom of the panel off entirely when I applied the red stripe on the top surface and when I flipped the panel to mask the bottom side, found a nice, ugly mist of red way out on the main, perfectly painted white base coat surface. Great!, re-mask the entire bottom of the panel and re-set up for a second session of white base coat, etc., etc......shot a day on this little error.

Some thoughts;
Spend the money and get the good masking tape. I found that 3M Vinyl Tape 471+ works and will give you good, sharp lines. With all the effort this takes, using this quality of tape on all your actual lines will be worth the cost. Use that blue stuff used for home painting walls , etc. on all the other areas where you are not painting against it. I used the blue stuff (Blokit or Frog tape) on my actual lines and got bleed through. If you were really diligent about going over every inch of the line with adequate pressure to get a 100% seal, you might get by. I was being careful and got a significant amount of bleed anyway. Use a ¼ or ½ inch vinyl tape on the line and then use the blue cheaper stuff to tape to that.

Next I will shoot the bottom of the bottom two panels. You can be darn sure I'll have the top surface COMPLETELY masked off tight after what happened doing the top surface. If I had this to do over again, I'd mask the entire wing off for red and paint both sides since my plan was to do the same pattern on top and bottom of each of the lower wing panels. This would have eliminated the overspray issue I created and also been more efficient use of a spray day. I just wasn't confident of the process or technique and didn't want to risk the entire paint job without knowing it would work OK.
I've already found out through experience that using standard 3M blue painters tape can still be easily removed after two weeks. I did this in a heated space where I store the wings which may have helped keep the tape pliable. This is really important otherwise going on advice from the EAA guy, he'd have me remove it within a couple hours after painting which would mean I'd have to mask right before I paint and then get it off right away. Two concerns he mentioned were having issues removing tape from a painted surface and having the paint pull up along the edge but he also had never tried to leave the tape on for any length of time. I saw neither issue at two weeks. In fact, there was no hint of an issue. I'm inclined to believe I could leave the masking job on the wing for several weeks at least while waiting for a good day warm enough to paint now that winter has settled in here. What that means is that I can (and will) mask everything now and then paint when I get a good day where the temps get above 55 F. Yesterday I painted with a temp of 56 -57F and raining some with no issues. This shot shows me finishing up masking for the underside of one of the bottom wing panels. The top is all done.

Notice that the 1/4 inch tape line is the 3M vinyl stuff  I mentioned which will define the boundary of the red field I will shoot next.  I'll move the paper up to the 1/4 inch tape and then use the blue stuff to tape to it.  Also notice that I'm not going to use the vinyl tape to mask off where the gold will go down after I finish the red.  What I ran there was 1 1/2 inch painters masking tape.  Since this is the bottom of the panel, I figured it wasn't worth running two lines of the vinyl since no one but pilots below me looking up will ever see this side.
Still haven't decided on what I'm going to do with the top wing panels. If I do the same pattern, it's gonna add more weight but if I don't I think it's going to look cheezy. Decisions, decisions......  It will be a miracle if I get enough weather to get this all painted without having to wait until next spring now.  We're really settled in with rain and cold weather here in Oregon already.  Anyone out there want to volunteer use of their heated paint booth?