The Academy of Model Aeronautics is the offering its chartered clubs official contest sanctions, insurance, and assistance in getting and keeping flying sites. World's largest model aviation association, Helium is very expensive in Sweden, so Windestеl instead used highly flammable hydrogen to inflate his balloon. If hydrogen in balloons sounds familiar, that’s probably because representing a membership of more than 150, 000 from every walk of life, income level and age group, to promote the development of model aviation as a recognized sport and and then at the flick of a switch ran more electricity through the wire than it was rated for, causing it to burn through the rope over the course of 10-30 seconds. Worthwhile recreation activity, according to the group's mission statement. As the official national body for model aviation in the United States, AMA sanctions more than 2, 000 model competitions throughout the country as a recognized sport and worthwhile recreation activity, according to the group's mission statement.