I am not one of nature's cyclists. I didn't actually learn properly until I was in my twenties. My bike is very old, very rusty and very, very heavy.However, I feel that I "ought" to cycle more, for shopping trips and the like. I quite like the idea of switching to a recumbent, but they are expensive (current available funds: zero).So, I'm playing with the idea of rebuilding my mountain bike into a recumbent (and learning how to weld on the fly?).In the sketch below;The black section is the back of the old bike, turned upside down.The blue section is the front of the donor bike.The red part would need fabricating somehow.I haven't thought properly about steering mechanisms, but probably under the seat, via cables to arms welded to the forks of the will-be-the-back wheel.Would the bike, as I have sketched it, in principle, work?I'm bothered about stability, especially at take-off and landing. Am I worrying unnecessarily? I have access to a second donor cycle. Is there any mileage thinking about "doubling up" the blue section, to make a trike? Not massively wide, but I could add luggage space, or an extra rear-facing chair-style seat.Brakes: before I cut up the bikes, am I right in thinking that I just remove the cables and levers from the handle-bars and add them to the under-seat steering?Gears: the donor bike is a mountain bike, but I never used all the gears anyway. This area is pretty flat - can I get away without any gears?Coasting: although the back of the donor bike ends up upside-down, it is still turning the same way, so I can still coast OK.I'm sure I've missed something obvious...Anyway, even though I've not decided to do this for certain, I'd appreciate any comments or thoughts.