Lost foam

                   this method is probably the best way to get into using composite materials, its fairly quick to do but each fuselage is a one off. you can make the wings using just a hot wire  and sheet the cores with ply , obeechi or balsa, so a complete plane can be made with just a length of foam cutting wire, and some baisic materials. As long as you cover your foam plug with tape, you can use epoxy or polyester resin, and then melt out the foam with acetone or petrol. Epoxy is stronger, polyester is cheaper and smellier. It is not to be underestimated for prototypes and one offs, making a mold is not really viable unless you want five or more parts in my opinion, or you just want to make a mold! It is also an opportunity to use up all those off cuts you have been hoarding up. 

Once you have a full size plan and side view of your fuselage, you are ready to cut out some foam. I use a bandsaw and just hold the paper plan onto the foam with pins, using a centre line as a reference point. The fuselage could be blocked out with a hand saw or coping saw, or you could make up cardboard templates and hot wire it out. The important thing is to get a square sided block with the profile and planform of your intended shape, and it should have nice flowing lines by sanding with a block to take out any ridges or imperfections. I have been recently inspired to do some lost foam fuselages by this build thread Joe is a master of this tecnique and it was a real eye opener to see his productivity. Was very suprised to see he makes his fuselages with the fin shape incorporated, and how many of the same concept he turns out. After roughing out a few, I am begining to see why he does it, some suttle changes make the fuselage look completely different. Its very quick to do and is great fun. Am building up to trying a fuselage with a fin, just have to be very delicate with it.