In the beginning I decided I would like to make a kite. I then decided that I would make a copy of my Revolution EXP as a) I like it, b) I had seen other people flying custom Revolution and they looked very nice indeed, and c) I knew it would be cheap as I had all the spars and stuff.
Thinking this was a harmless (and common) thing I asked various questions on the rec.kites usenet group. And I got some very angry responses saying what I was doing was illegal as I was copying a commercial & patented kite (which it was). I responded in an angry way basically saying that making it for personal use was legal in the UK.
However reading some of the other responses and doing some research led me to believe that it's not that simple. It appears that the personal use thing is a bit of an urban myth - if it's true I can't find it on the UK patent office web site.
So here are my thoughts, but bear in mind I am no expert in law, so what I put here is not advice to do or not do do, it's just thought to help you make you own mind up. And read the archives of rec.kites - not just my posts, but read old posts as well.
My thoughts on the moral rather than legal issues are like this:
Totally Wrong Copying a commercial & patented design to sell. As far as I can see this is a very big moral and legal no-no and if/when it comes to the attention of the patent owner almost certainly will result in legal action against you.
Sort of Wrong Making a copy of a commercial kite as a gift to a friend or relative. Borrowing someone else's kite to measure and effectively clone. Copy exactly your own kite, down to all the last details & graphics - again cloning.
Sort of OK Making a personal copy of a kite you own for your own enjoyment. Making a copy of a commercial kite you have seen, but you are guessing as to virtually everything.
Totally OK Making a kite from you own design.
It's up to you! Just think about what you are doing & why you are doing it. You will be able to find out my views by looking elsewhere, both here on the kitejan site, and what I have written elsewhere - just because I have come to a conclusion that works for me morally doesn't mean that you don't have to work it out for yourself.
Check out the kite designer Peter Lynn's thoughts about copying his commercial designs from the February 2000 newsletter (scroll down to February).