The following is quoted from the "Ultralight from scratch, knowledgable and reasonable input requested" thread post #67. Thanks, useful info but advisory, not regulatory. Many references are made to European requirements of span loading and weights for gliders. I do not believe these limitations apply in the US. My search turned up the Basic Glider Criteria Handbook.The "Basic Glider Criteria Handbook" deals with guidance for design and structural issues. My concern was with regulations and requirements as has been discussed with regards to FAR 103. The Basic Glider Criteria Handbook does not refer to regulations nor contain minimum specifications for gliders such as sink rate, L/D, stall speeds, wing loading, or span loading. I'm cool here. Apparently we were discussing two different topics. This reply is copied to a new thread titled "Glider Performance Limitations or Requirements" for those who wish to make additional comments.