Save that balsa.

Many years ago I built an XLT r/c pattern plane. It was designed by Joe Bridi and the construction techniques he used are still relevant today. I don't like to waste wood by hollowing out a large and expensive block of balsa. What Bridi did was to use triangle stock and a top plate of suitable size to take the place of the inch thick balsa that will be reduced to a tenth of it's original size. Bridi trimmed one of the 45 degree ends so the triangle could be glued to the fuselage side in place of the block. then a top plate is glued to the tops of the triangles and the proper radius drawn on an end. After carving the outside to a rough dimension I used the shoe shine method with a strip of 80 grit sandpaper to smooth the outside then the piece is removed and the triangle stock is hollowed saving tons of balsa and time. There are lots of kits on the market that have blocks of balsa that can be replaced with this method and the blocks saved for something better, like selling them on ebay or making your own triangle stock.