I'm covering the wings with Poly Fiber. I like it because it's easy to apply, less sensitive to humidity (I live in the south), and for a wooden airplane it's less flammable than dope. I have found a problem with it. It's easily stained from dirt, bird stuff, etc. There is no way to remove stains if they happen.
The process requires a cloths iron which will hold temperature to plus or minus 10 degrees F. The iron needs to be calibrated at 225, 250 and 350 degrees. To do it you need a thermometer, 1/2" stack of paper towel, and some heat sink to assure the thermometer senses the temperature of the iron correctly.
The instructions call for an iron which will not shut off when setting still. I don't think they make one anymore and my old one died. The plan is you set the iron with the sweet spot on the thermometer bulb on the pad and mark the dial for the 3 settings. Unfortunately the iron, which Aircraft Spruce sell shut's off after 30 seconds setting flat and 8 minute on the heel. I strapped 2 irons together to hold the padding tight and tipped the iron flat every 5 minutes so it wouldn't shut off while I slowly adjusted the dial, let it heat up and then cool down to split the spread of high and low. It took a few hours to get it marked for the 3 settings. When it's heating there is a green light on the side of the handle. If it turns red you've let it set still too long. Tip it from vertical to horizontal and it comes back on.
With the iron calibrated and the leading edge coated with 2 coats of Poly Brush, I cut a piece of fabric to wrap from trailing edge around to trailing edge. Normally if you have fittings sticking up a couple inches in the middle of a wing you ignore them and cut the fabric after the first shrinking so the fabric can position itself. The strut fittings at the root ribs are too big and in the wrong place to ignore. I cut slits for them with a breakaway knife starting at the inboard corner and just big enough to clear the fittings. I'll have to be more careful shrinking the fabric so it doesn't tear at the fittings.
I like the breakaway knives. when the blade gets slightly dull break it off and keep working. They make the blades with this 60 degree point and with a pointier 30 degree point for getting in holes, etc.
With the fittings poking through I started by gluing the fabric to the end ribs from the bottom side only. Keep it loose.
Next I fit it to the trailing edge cut out. I had trouble with stretching it to fit the curve because I had the iron at 225 degrees. It takes closer to 250 to stretch it.
I cut slits so I could stretch smaller sections. With some work and the right temperature you can do this without slits.
I did the cut out on the top and the stretched the top of the end ribs to fit. It looks tighter in the picture than it is. You don't need it tight. It will shrink quite a bit.
I left it for the glue to dry before shrinking it. When I went back out to work on it today it started raining so I'll wait for a dry day.
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