Jeez, this takes me back. I've enough trouble remembering electronic stuff. (Supposedly my job, but it's mostly form filling.)
If only I could have Googled the answers back then! Oanyhoo, just want to post this page for TAMBers as apart from answering GRB's questions, it tells us how aeroplanes fly and more importantly, how to bend a football
http://francesa.phy.cmich.edu/people/andy/physics110/book/Chapters/Chapter9.htm#c