last changed : 01/10/2003

Note : 1 meter = nearly 3 ft (3,28 ft), 1 yard (1,093 yard) or 39 inch (39,37). Measure are decimal in this page (1.5 ft = 1 and a half ft)

Required hardware :

• A post 2 meters long,
• 1 meter of red and white tape (used on roadwork),
• adhesive tape, scissors, string for the possible last time fix up,
• 4 lbs of payload (whatever),
• 200 meters of good string,
• Optional : a small 12V fan with cable and small lead battery

Setup (getting ready)

To inflate the balloon it is needed to :

• Choose day and time : good weather sunny day no clouds, no wind (see the page "Estimation du vent" in french) or with a very light wind , possibility to shelter behind a wall, early in the morning (from 10/11h the thermal convection create some wind).

  More the outside air is cold and dense heavier will be the load lifted.
  The best results will be on
  the snow (high albedo)
  during high pressure (anticyclonic).
  To learn more,
  Solar balloon Theory (in french)

• Make an air sock with a post 2 meters long and a piece of red and white tape 2 feet long. Put this air sock at some distance from the launching site.
• Lay down the balloon on the ground, the bottom of it (open end) up into the wind.
• Inflating the balloon : there are different ways of doing this :
  - with a fan it's easy and fast,
  - with your arms ! there is no problem for a 4m (13 ft) balloon : sit down on the ground facing the opening of the balloon. With your knees you hold down the part of the envelope that is under and with your hands grab the part of the envelope that is above and move it up and down. This will suck air into the balloon.
• Pretty fast, the sun will heat the air into the balloon and the envelope will begin to rise. The balloon will finish inflating itself alone while in the air.
• Load up the basket : the heavier it is the slowest is the and the lowest it's cruising altitude. With a load of one lb (4 to 8 meters/s)(700 to 1500 ft/min) and the max. altitude will be more than 50.000 ft (measured by Gérard AUVRAY the July 6 1997).
  See also Conseils pour la photographie aérienne (in french).
• After about 5 to 10 min, the balloon is able to lift it's payload.
• Check the wind (speed and direction) ; check the risks : electric power lines, buildings or chimneys...
• Let it rise with a very long string (ours is about 200 meters !) release it for a free flight.

Be careful to the wind !
As soon as the string is tightened the balloon will behave like a spinnaker sail and will be deflated and dragged down...

Rules for a free flight :

In order to launch a balloon for a free flight it is absolutely mandatory to check the rules of your country !
you are responsible !

Good flight !

Deflating :

The easiest is to remove of the payload and the string and have the balloon turned upside down (the open end being up at this time the hot air will escape through it). Finish by pushing out any remaining air with your. Store the balloon in a big bag without packing it !

Warning ! when the deflated envelope is left still on the ground under the sun, the temperature will rise quite fast and it may damage the envelope.

Do not leave the empty envelope under the sun !
Do not leave the bag containing the envelope under the sun (or worse into a car parked under the sun) !

in order to improve this site, we need some information about what you have done and how you did it...
In order to better understand the performances of those balloons, it would be interesting to have some data's such as : outside temperature, inside temperature , altitude, atmospheric pressure, diameter and volume of the balloon, envelope thickness, maximum load lifted, actual load of the day, weather, etc.

Thank !