Largest payload balloons are 'sounding' balloons.
Kaymont Consolidated Industries, Inc.
21 Sprucetree Lane
P.O. Box 348
Huntington Station, NY 11746
Phone: 1-800-644-6459
Fax: 631-549-3076
E-Mail customer service
We use Totex weather balloons. They seem to be the best quality. Balloons are sized by their weight in grams. Kaymont currently carries two sizes, 800 and 1200 grams. The 800 gram size will lift 3-4 lbs to 100,000 feet. The 1200 gram size will take a full six pound payload to 100,000 feet. Prices are about $45.00 each for the 1200 gram balloons. Kaymont accepts telephone orders and credit cards.
What you want is enough gas to lift the balloon, your payload, radar reflector and parachute plus six ounces to one pound of extra lift. One pound of extra lift will give you about a 1000 foot per minute initial rate of climb. This will give you about a 2-3 hour ride to 100,000 feet. On a very calm day with slow winds aloft, you can put in six ounces of lift and get a longer trip up and more usable time at high altitude. Here's the WB9SBD method of achieving the desired amount of lift:
Construct a simple scale by suspending a strong rod from a rope tied around its middle.
Hang your payload, parachute, radar reflector, suspension cables and EVERYTHING else that will fly EXCEPT the balloon to one end of the rod.
Hang a one or two gallon plastic jug from the other end of the rod.
Fill the jug with water until the rod is balanced.
Add six ounces to one pound of extra weight to the payload end. (Hint: bread comes in one pound loaves - a WB9SBD discovery)
Add enough water to balance the rod again.
You now have a jug of water that weighs exactly as much as what your balloon will have to lift plus 6 to 16 ounces extra.
55 Shepherds Lane
Totowa, NJ 07512
Phone (voice): +1 (973) 790-3366
Phone (fax): +1 (973) 790-1275
Email info@kaysam.com
Big Balloons:
Gas:
Helium at the welding supply shop. Get pre-approved to avoid tank deposit. Rent tank and regulator. Size K or T will fill a 1200 size balloon with extra left over.