When I bought my house, there was this partial roll of Tyvek® housewrap in the basement. I don't know what thickness it is. It had been sawn in half, so it's not full width. Even so, there was enough width that I could build a Peter Lynn "Pilot" with the profiles and keels in one piece.
See Pilot Parafoils from GKPI, their Pilot 50 photo, and the plans for building a similar one here. You can also download an Excel spreadsheet that will calculate pattern dimensions, from here (hosted by Dave Ellis). If (like me) you don't have Excel to play with the spreadsheet, I recommend that you download OpenOffice (open source, for several different platforms, and free). The spreadsheet also calculates the overall area of the finished kite, which is a better indicator of its lifting power.
For this one I used a scaling factor of 0.60, reducing it to 18 square feet down from the standard 50 square feet. I intend to build a bigger one out of ripstop nylon, perhaps 25 square feet. To get the dimensions for a half sized (25 square feet) one, use a scaling factor of 1/square root of 2, which works out close to 0.7071.
With strategic placement of the templates (and allowing some wasted material), I managed to keep the printed graphics mostly on the inside where it's less obvious.
It's rather slippery stuff, so I used a lot of green low-tack masking tape to keep edges lined up for sewing. Early in the project, I found that the regular beige masking tape would sometime shred off a few surface fibers as you remove it.
Sewing it was pretty much like sewing coated ripstop nylon (spinnaker cloth), except it was a bit noiser, and any needle holes are quite obvious. It was easy to hot-cut too, with the angled chisel point on my woodburning kit iron. It melts at a much lower temperature than nylon fabic. I didn't have to hot-cut it though, because it's a non-woven material. I could have used scissors, since the cut edges won't fray.
For the nine bridle line tabs I sewed in doubled loops of masons' line (a fairly soft braided nylon cord, rated at 143 pounds or 65 kg) from the keel edges up to the seam for the bottom skins. That was just a question of taping it into place and running a three-step zigzag stitch over it.
Here it is tethered to a stake, on a meter or so of flying line. You can just barely see the five bits of masons' line I sewed into the trailing edge, to be used as pigtails to tie one or more tails or drogues to, in a variety of configurations.
With a commercially-made windsock as a tail. Whenever it needs a tail, this is what I usually put on it.
In this photo I used my 10 foot long spinsock as a tail.
I usually fly it on 100 pound braided dacron line.
Here's a short movie, in MPEG-4 video format (4.5 MB) or Quicktime MOV format (1.3 MB) where it was used to hoist the spinsock attached to the flying line about 20 meters down from the bridle. I wasn't using a tail, and it was still fairly stable.
There are a number of threads in the Kitebuilder.com forum that discuss the Pilot 50, with people's experiences in building, flying, and modifying the plan.
Pilot - Peter Lynn - review of plans, and a lengthy discussion
I'm thinking I need a lifting kite for stronger winds - to be used for KAP
It appears to be a remarkably adaptable and forgiving design.
David Gomberg has kindly provided a useful guide to tuning the bridle lines of a Pilot for stable flight, at Tuning Parafoils and Flowforms.
The following Spring...
May 23, 2009: After about 12 hours of accumulated flying time (over the fall and winter), I spotted a bit in need of repair.
The panel with the red and black printing is the centre one-piece keel and profile/rib panel. For some reason, I used just a single stitch to sew the bottom panels (to the right and left) onto it, and it has started to come apart. Perhaps I forgot to back-stitch it. There are no tears in the Tyvek, so it was easy to fix with a few inches of three-step zigzag. That's the only significant sign of wear that I've found yet, other than it being wrinkly from being stuffed into the bag.