All entries

The complete roster, in document order. Every entry is one problem in the airflow, and the hinge that answered it.

Eighteen entries across five sections
No.	Entry	Section	What it covers
01	The flapping hinge	Rotorcraft	On a rotor moving forward the advancing blade meets far more airflow than the retreating one; letting each blade hinge freely up and down is what stopped the resulting roll from wrecking the machine.
02	Dissymmetry of lift	Rotorcraft	The underlying problem stated plainly: one side of the disc is always doing more work than the other.
03	Autorotation	Rotorcraft	An unpowered rotor keeps turning in the airflow as the machine descends, which is what makes the whole configuration safe rather than merely clever.
04	Direct control	Rotorcraft	Tilting the whole rotor head rather than working control surfaces in its wake was the step that made the machine properly flyable.
05	Jump take-off	Rotorcraft	Spinning the rotor up on the ground and then changing pitch lets the machine leave almost vertically.
06	Juan de la Cierva	Engineers	The engineer whose successive machines worked through the rotor problems one at a time, and who published as he went.
07	The drawing office	Engineers	Rotor work is geometry before it is anything else, and the drawings are where the argument was conducted.
08	Test flying	Engineers	Each change had to be flown, usually by the people who designed it.
09	CASA	Manufacture	The Spanish manufacturer that turned aeronautical design into an industry, building under licence and to its own designs.
10	Licence building	Manufacture	Much of the industry's early work was building other people's designs, which is how the tooling and the workforce were created.
11	Materials and jigs	Manufacture	Tube, fabric, plywood and later alloy, each with its own tooling and its own repair practice.
12	Cuatro Vientos, Madrid	Aerodromes	One of the oldest aerodromes still in use, and where the first practicable rotorcraft flew.
13	Getafe, Madrid	Aerodromes	A works aerodrome beside a factory, which is a different kind of place from a flying field.
14	Tablada, Seville	Aerodromes	An early southern airfield whose buildings survive better than most.
15	Sabadell, Barcelona	Aerodromes	A general-aviation field of the kind where light aircraft work actually happens.
16	Museo del Aire	The Collection	The national collection, which is the physical archive of everything the industry built and much that it did not.
17	Rotor-head cutaways	The Collection	A sectioned assembly explains in one look what a page of text struggles with.
18	Drawings and archives	The Collection	The paper is the other half of the collection, and it is where the reasoning is.