I recently caught the bug that suggests one could build a decent recumbent for much less than the purchase price of a new one, so off to garage I went . .
Ok, not quite, but I started collecting bicycle frames and parts wherever I could find them for free or cheap. So far, I've only spent about $20 on junked/recycled bikes, with the exception of a $15 set of Hayes disc calipers and the $30 Shimano triple crankset I got off of E-bay. Another $16 for the raw mild steel and I'm more or less set with all that I need to make the bike complete (but leaving a fair amount of room for improvement on other components).
One thing which I would suggest to anybody is to start out with a proven design and modify carefully from there. There are some very good reasons certain things are placed where they are, and ignoring that is just making things difficult on yourself. How do I know?
Looks like a good start on the surface doesn't it? Unfortunately there were two critical problems with the design that I opted to change.
The first thing had to do with the strength of the connections to the front and rear tubes. With the type of stress that would be placed on them, I was advised that even if the welds themselves held, they would most likely end up flattening buckling.
The other issue was that the seat tube angle is really too steep to be comfortable on a recumbent of this type. So I decided to just start over on the rear with a completely different set of rear stays from a full suspension mountain bike. The front was just reworked without the bottom bracket junction.
Here's how it looks today- and no, the wheels were neither free nor somebody elses junk.
I also forgot to point out that the revised frame eliminated more than a foot off the length of the bike, and the head tube angle was laid back a hair more to induce a little bit of trail into the steering (the distance the contact patch follows the head pivot line). Without making that change, it might have been a quick handler, but I would've needed quick hands, and certainly no riding without hands.