Leading Edge Inflatables
From FoilDesign
Original design patented by BRUNO and DOMINIQUE LEGAIGNOUX (see patent, PDF available from Zeroprestige.
Abstract
A very light wing, configured like a spherical segment, is intended to be used in the traction and lift of various loads. The wing includes a leading edge and a trailing edge and an inflatable armature covered by a flexible envelope. The surfaces of the wing are configured in the shape of an aircraft wing profile and the edges of the wing curve in two planes. The leading and trailing edges of the wing are oriented to intersect near the tips of the wing, and each of the tips of the wing receives a control rope via an adjusting plate. The control rope is passed through a pulley mounted on a craft to be displaced by a person through a harness. The wing can be used in sliding sports, yachting and gliding.
LEIs have inflatable frame and leading edge; single skin (top skin of profile); four lines, front lines are power, the back for stearing and AoA control.
Contents |
Where do I start?!
Try Sauls LEI kites (Zero Prestige). A 12 meter is the most common size here in Europe, and will work in winds approx 15 mph to 25 mph (depending on skill level.) Materials, Dacron (2.9 oz) for the leading edge and the ribs, AIRX600 for the canopy (see Materials Questions for more ideas) Bladders:
Tried and tested plans
- Open Source LEI's: Zero Prestige
- Bat Wing
- Gigis Kites
Building technique
There are various ways in which to build your LEI.
Technique 1
See Sauls technique
Technique 2
Without the LE canpoy dacron reinforcement.
- Print the plans in overlay mode.
- Place the material over the plans and trace each panel of the canopy out (x 2) use a good CD-RW pen or a transparent overhead projector pen (these don't smudge)
- Place the LE material over the plans and trace each panel out (x 2). White dacron is good for this because it is opaque and you can see the plans through it. A light box may also be used on dark materials)
for your first kite mark on all panels:
- panel number,
- left or right side of kite (I mark them as "panel 12 A" and "panel 12 B")
- top of sheet (half the sheets are sewn with the marks on the bottom, the other half with them on top)
- LE and TE (some are almost square and can be confusing)
- Which direction the center and tip are.
If you're making a number of kites using the same plans, making templates is a good idea. Cut the template to the size of the panel (without the seam.) When you draw around the template, put the pen in the center of a new washer, then roll the washer around the template to draw the seam. The size of the washer determins the size of the seam.
cut out material
- Cut out the panels (scisors or hot cut)
- Same for the ribs.
- and LE.
Hot cutting the material will seal the edges, preventing fraying.
sewing
- Sew the canopy together. Sew the seams flat with a zig-zag or tripple zig-zag stitch.
- Sew the ribs together. Sew the seams flat with zig-zag or tripple zig-zag.
- Add a reinforced valve hole.
- Add the velcro to seal the rib end.
- Close the end of the rib where it attaches to the LE. See diagram
- Sew the LE together.
- Add the rocket struts (depending on plan)
- Add one or two valve holes. Place these under the canpoy.
- Attach the ribs to the LE (make sure the rib is the correct way up)
Tips: Surfplan printouts
The pages are all printed with cross-marks in the corner. Align these marks to get the pages together correctly. The overview page gives you a good idea of where to put each piece, and each page is also labelled with an x and y coordinate.
Tips: Materials
As for your materials, chikara is not the best for inflatables, as it stretches over time when under strain. Most polyester cloths have better stretch characteristics, and are better for inflatables, but make sure they are coated water resistance. Don't go more than .75oz cloth for the sail, and for the Dacron, get as light as you can. I think somewhere around 3-4oz is normal for the struts.
