Some lanyards we have sewn for PPG’s and PPC’s
Fabric and Sewing
The fabric i like best is standard white (white is the cheapest) 3.8 oz. sail cloth common on day sails on sailboats. Got a bunch of 4.2 but it is just too heavy and certainly not needed for ultralights. i buy it in 100 to 150 yd. rolls. i have 18″ 36″ and 60″ widths but have found that the 18″ (although it looks cool on the 23bis. and 24’s it’s a waste of time to sew all those seams. We counteracted the weight issues my supplementing the aluminum battens with carbon fiber every other one…but i will never design a wing sail like that again. The 60″ is just too wide. There is a lot of flop in the sail and no matter what you use for a batten…it ain’t gonna work. The 36″ is like the story of the three bears…”but my porridge is just right!” 36″ wide fabric is the ultimate width for strength, minimum sleaze, dependability, and ease of handling/construction. If you are designing the structure, do it in 34″ increments. (You have to allow for a 2″ batten overlap on every panel, and don’t forget the 4″ foldback on both ends. On this design i am using a 8″ overlap on the ends with a 2″ inbound batten pocket, i plan on experimenting with an outbound wire to form a Horner tip. If it works, i will do a write up later on. The thread i use is V92. My eyes aren’t what they once were so i need to use color on the main spool…any color, currently using blue for no other reason than that’s what i had on hand. Can still use white in the bobbin (bottom), i buy the bobbins, don’t waste my time winding them. If you can’t see it you can’t sew it straight. My favorite needle is a Schmetz #110 size 18. Some people will tell you that this needle is notorious for picking up glue from the seam tape due to the large, triangulated shank but i like the rigidity—give it a shot of WD-40 every 20′ or so and it ain’t a problem. The stitching pattern default is a 4mm width by 6mm long zigzag, the square doesn’t seem to suit.
The heaviest fabric i use is 3.8 sailcloth (from Sailrite or Challenge Sailcloth) for single sided wings, single sided rudders, ailerons, elevator/stabilator. IF i make double sided ailerons, rudders, etc. i don’t use sailcloth. For consideration, Ceconite makes three fabrics, Uncertified light at 1.87 oz. C-101-5 at 2.9 oz. and C-101-4 at 3.4 oz. Superflite is also a contender offering 104 at 1.7 oz., 102 at 2.7 oz. and 101 at 3.7 oz.
My choice is normally SF-102. It handles well, is not as sleazy as the Ceconite alternative and holds a stitch without the walking foot hedging the fabric forward. It shrinks nice with a heat gun and is not capable of ‘crushing’ most… most ultralight structures. I generally design a ‘sock’ to slip over the structure with a short side folded over and glued. Except on ailerons, i normally select the largest dia. tube available to use for gluing. The glue i use is Loctite spray adhesive. (Contact cement) It works well with very little masking and once heated and shrunk it takes M.E.K. to remove it. Once the fabric is shrunk onto the frame i give the decal area a light dusting of white spray paint, so the decals stick. I guess you could paint the whole thing, but i never have.