The fuselage was a welded, braced steel tube construction, with wooden frames (formers and stringers) and fabric covering.
Initially, the wing was a new-design two-spar monoplane wing covered with fabric.
In 1939 the fabric-covered wing was replaced by one with stressed-skin metal wings. They added a three blade propellor and the Merlin III engine then too.
Great flying airplane...love to have one!