Below is a list of the basic steps of building a balloon envelope. Each one of these steps can have a great deal of detail behind it. We'll be filling in these details over time. In the meantime, please feel free to contact us (or ask an experienced balloon builder) if you don't understand something.
  1. Attend the next XLTA rally and pick the brains of a whole bunch of folks who've already done the following steps.
  2. Sew each set of 13 panels into gores. (To get a consistent look, make sure that the folds on these horizontal seams are always pointing the same direction -- either up or down.)
  3. Install parachute envelope attachment loops to webbing-"stickmen" at a point 7' 10" from port edge.
  4. Install parachute velcro envelope tabs (1.5" wide and 4" long made of the hook side of velcro) starting 8" from port edge (the far end of the tabs will be 12" from port edge).
  5. Measure & cut web pieces for mouth cable reinforcement web pieces: 16 @ 4 ft. of 1" wide tubular webbing
  6. Install N-numbers on two panels, 180 degrees opposed, at lower equator. Minimum 3" tall, bold san serif font.
  7. Sew the 16 gores together. Each gore should have at least 8' of load tape hanging off the end at the top and 2' of load tape extending beyond the bottom. "Double-up" the bottom 4' of each tape with a 4 ft. piece of 1" tubular webbing sandwiched between the load tape and the envelope fabric. Both the tubular webbing and the load tape will be extending 2' beyond the bottom of the fabric.
  8. Install pyrometer sleeve and or loops (not needed if using wireless pyrometer) along one gore seam.
  9. Close final vertical gore seam. (There is an important trick to this that can save you A LOT of work! It's too complicated to describe here. So you'll have to ask somebody about it.)
  10. Sew mouth hem with 1.5" wide 5038-type-4 webbing.
  11. Sew mouth cable web/loop fold-backs (minimum 24")
  12. Hem top port edge with 1.5" wide 5038-type-4 webbing.
  13. Install the two parachute line routing ring bridle attachment loops (12" of 1" wide 5038-type-4 webbing folded over with loop pointing downward) on gores 5 & 6 at a point 12 ft above mouth. Install the 2 bridle lines & the guide ring.
  14. Measure and trim to length, parachute port opening overstraps -- 16 pieces at 8 ft. Sew loops on ends leaving finished length 7 ft. from the port edge to center carabiner (If you prefer to substitute a steel ring rather than a carabiner that's fine. However make sure that the ring has a tensile strength of at least 2,500 lbs.) Attach all 16 loops together at center of port by sliding them onto the locking carabiner.
  15. Cut & rough assemble parachute top panels
  16. Fold rough chute, scribe and cut parachute. Mark edges in gore sections (16).
  17. Install temperature tell-tale in chute center (inside)
  18. Install parachute retrieval line attachment point, center of chute, 12" diameter circle with webbing criss-cross.
  19. Hem edge of chute with 1" wide 5038-type-4 webbing.
  20. Install chute velcro tabs (1.5" wide and 4" long) velcro pile (a.k.a. loop) and webbing loops for line attachments.
  21. Install & rig parachute confluence lines, centering lines, actuation line, and retrieval line.
  22. Number gores on parachute tabs, parachute port, and mouth.
  23. Assemble & install cables at mouth with delta links.
  24. If installing a skirt, assemble & install the 8 pieces of skirt fabric, skirt ring, and (if desired) handling lines at the top-center of the mouth
  25. Assemble and attach crown line, 82 ft finished.
  26. Cut & assemble envelope storage bag.
  27. Pack balloon
  28. Test inflate
  29. Obtain airworthiness certificate from the FAA.
  30. Pat yourself on the back ;-)
  31. Test fly your balloon for the required 10 hours.
  32. Sign up and show off your handiwork at the next XLTA rally

All information on this site is subject to the following disclaimer.

The balloon plans and descriptions provided here are
Copyright 2007-2008 Daniel Nachbar and Paul Stumpf
Creative Commons License
Creative Commons Attribution-Share Alike 3.0 Unported License.