Go on then, what are they for?
My first post retirement project is building a Bob Copland Wakefield endurance rubber powered model aeroplane.
The fuselage is circular and is made from balsa rings with 24 stringers evenly spaced radially.
The cardboard formers are used to wind 1/8" x 1/32" balsa strip round and glue the laminations together. The cardboard rings are then slid onto a 1/2" square armature and the rings spaced appropriately to form the longitudinal profile. Three quarters of the stringers are then glued in place before removing the armature and the cardboard formers and the remainder of the stringers are then glued in place.
The model will look something like this but with a circular cross section instead of an oval one - I'm preparing oval formers for a second model.
The construction method looks like this
Copland was recruited by Hawker as a draughtsman and his first project was to design the rearview mirror for the Hawker Hurricane. The last plane that he worked on was the Harrier Jump Jet.