last changed : 01/10/2003

Required hardware :

- a roll of black 33 gallons trash bags.
VERY IMPORTANT! Use 13 µm thick black bags ( .5 MIL )!
- a measuring tape,
- scissors,
- a knife with a rounded tip and small dents on the sharp edge
- a roll of tape 19 mm x 33 m
- 11 meters of sewing thread.
- a white out pen,
- a light weight basket (small plastic can : yogurt is fine),
- a living room !

Building Time: 3 to 6 hours with 2 people.

For a single person it is difficult and, above 2 people, the others are only giving useless advises !

Process :

0 - Clear some space in your living room !
1 - unroll and put on top of each other 12 bags. Align the lower part of the bags (side with the bonding).
2 - Cut as close as possible from the bottom to eliminate the bonding (12 mm).
3 - Cut with a knife all the bags along one of the edges.
4 - Once opened, this makes plastic sheets of around 167 cm by 100 cm.
5 - Building the lower part of the balloon : Stack  6 sheets making sure edges are aligned.
6 - Fold this stack in two, so that one longest side covers the other one. You obtain a 167 cm by 50 cm stack.
7 - Using the white out pen, mark a point at 20 cm from the fold (pli) and draw a line to the other corner (see drawing).
8 - Cut along the line using the scissors.
9 - Unfold the stack of plastic sheets.

10 - Align side by side 2 sheets with the narrow ends on the same side. Tape them together along the whole length. One person aligns the sheets with a slight overlap while the other one tapes.
11 - Repeat this task five times and roll the assembled sheets while progressing.
12 - Building the half upper balloon : Repeat operation 5 to 11 with the remaining 6 sheets following the drawing. Assembly is slightly more difficult due to the cranked shape.
13 - Balloon assembly : put side by side the upper and the lower balloon assemblies (tape should be on the same face). Assemble with tape.
14 - Close the balloon by taping from top to bottom (tape on the same face).
15 - Finish-up the top of the balloon to avoid leaks !
16 - Turn the balloon inside-out like a sock so that tape is inside the balloon. Tape outside is not pretty and bonding is more exposed to sun rays.
17 - Reinforce the bottom of the balloon with tape close to the edge (5 mm).
18 - Tape six 1.5 m sewing threads onto the bottom of the balloon, making sure that at least 6 cm of that thread are taped to the balloon (see picture). Do not apply tape on tape as bonding is not very good.
19 - Tape the 6 lines to the yogurt cup.
20 - Attach another 2 m line to the bottom of the yogurt to hold the balloon.
21 - Your balloon is finished. Weight should be around 220 gr !

How to launch your balloon :

• Choose your day : clear sky, little or no wind, early in the morning before thermal activity
• Lay the balloon on the ground with the opening in the wind if any.
• Inflate the balloon : several solutions :
   - with a fan, it is easy
   - with your arms! It is still easy enough for a small size balloon: knees down in the opening of the balloon to maintain one of its side on the ground. Grab, with your hands, the other side and move it up and down to let air get into the balloon.
• Very fast the sun is going to heat the air in the balloon and the balloon is going to raise. It will finish to inflate itself thanks to the sun heat.
• Load the basket. The biggest the load is and the smallest the vertical speed and the maximum altitude are.
• Hold the balloon using the line attached to the basket.
• After 5 to 10 minutes, the balloon is capable to lift its load.
• Release the balloon being careful that the wind will not take it towards electric lines or buildings.
• HAVE FUN

FAA Part 101 : regulation applicable to free balloon

101.1 Applicability.

(a) This part prescribes rules governing the operation in the United States, of the following :

(1) Except as provided for in §   101.7, any balloon that is moored to the surface of the earth or an object thereon and that has a diameter of more than 6 feet or a gas capacity of more than 115 cubic feet.

(2) Except as provided for in §   101.7, any kite that weighs more than 5 pounds and is intended to be flown at the end of a rope or cable.

(3) Any unmanned rocket except :

(i) Aerial firework displays; and,
(ii) Model rockets :

( a) Using not more than four ounces of propellant;
( b) Using a slow-burning propellant;
( c) Made of paper, wood, or breakable plastic, containing no substantial metal parts and weighing not more than 16 ounces, including the propellant; and
( d) Operated in a manner that does not create a hazard to persons, property, or other aircraft.

(4) Except as provided for in §   101.7, any unmanned free balloon that --

(i) Carries a payload package that weighs more than four pounds and has a weight/size ratio of more than three ounces per square inch on any surface of the package, determined by dividing the total weight in ounces of the payload package by the area in square inches of its smallest surface;
(ii) Carries a payload package that weighs more than six pounds;
(iii) Carries a payload, of two or more packages, that weighs more than 12 pounds;
(iv) Uses a rope or other device for suspension of the payload that requires an impact force of more than 50 pounds to separate the suspended payload from the balloon.

(b) For the purposes of this part, a gyro glider attached to a vehicle on the surface of the earth is considered to be a kite.

[Doc. No. 1580, 28 FR 6721, June 29, 1963, as amended by Amdt. 101-1, 29 FR 46, Jan. 3, 1964; Amdt. 101-3, 35 FR 8213, May 26, 1970]